https://source.android.com/ 
/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.media;

import android.annotation.IntDef;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.RequiresPermission;
import android.annotation.SdkConstant;
import android.annotation.SdkConstant.SdkConstantType;
import android.annotation.SuppressLint;
import android.annotation.SystemApi;
import android.annotation.SystemService;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.bluetooth.BluetoothDevice;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.media.audiopolicy.AudioPolicy;
import android.media.audiopolicy.AudioPolicy.AudioPolicyFocusListener;
import android.media.session.MediaController;
import android.media.session.MediaSession;
import android.media.session.MediaSessionLegacyHelper;
import android.media.session.MediaSessionManager;
import android.os.Binder;
import android.os.Build;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.Process;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.SystemClock;
import android.os.UserHandle;
import android.provider.Settings;
import android.text.TextUtils;
import android.util.ArrayMap;
import android.util.Log;
import android.util.Pair;
import android.util.Slog;
import android.view.KeyEvent;

import com.android.internal.annotations.GuardedBy;

import java.io.IOException;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executor;



AudioManager provides access to volume and ringer mode control.

/**
 * AudioManager provides access to volume and ringer mode control.
 */
@SystemService(Context.AUDIO_SERVICE)
public class AudioManager {

    private Context mOriginalContext;
    private Context mApplicationContext;
    private long mVolumeKeyUpTime;
    private final boolean mUseVolumeKeySounds;
    private final boolean mUseFixedVolume;
    private static final String TAG = "AudioManager";
    private static final boolean DEBUG = false;
    private static final AudioPortEventHandler sAudioPortEventHandler = new AudioPortEventHandler();

    
Broadcast intent, a hint for applications that audio is about to become
'noisy' due to a change in audio outputs. For example, this intent may
be sent when a wired headset is unplugged, or when an A2DP audio
sink is disconnected, and the audio system is about to automatically
switch audio route to the speaker. Applications that are controlling
audio streams may consider pausing, reducing volume or some other action
on receipt of this intent so as not to surprise the user with audio
from the speaker.

/**
     * Broadcast intent, a hint for applications that audio is about to become
     * 'noisy' due to a change in audio outputs. For example, this intent may
     * be sent when a wired headset is unplugged, or when an A2DP audio
     * sink is disconnected, and the audio system is about to automatically
     * switch audio route to the speaker. Applications that are controlling
     * audio streams may consider pausing, reducing volume or some other action
     * on receipt of this intent so as not to surprise the user with audio
     * from the speaker.
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_AUDIO_BECOMING_NOISY = "android.media.AUDIO_BECOMING_NOISY";

    
Sticky broadcast intent action indicating that the ringer mode has
changed. Includes the new ringer mode.

See Also:
  • EXTRA_RINGER_MODE
/**
     * Sticky broadcast intent action indicating that the ringer mode has
     * changed. Includes the new ringer mode.
     *
     * @see #EXTRA_RINGER_MODE
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String RINGER_MODE_CHANGED_ACTION = "android.media.RINGER_MODE_CHANGED";

    
See Also:
@hide
Sticky broadcast intent action indicating that the internal ringer mode has
changed. Includes the new ringer mode.
/**
     * @hide
     * Sticky broadcast intent action indicating that the internal ringer mode has
     * changed. Includes the new ringer mode.
     *
     * @see #EXTRA_RINGER_MODE
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String INTERNAL_RINGER_MODE_CHANGED_ACTION =
            "android.media.INTERNAL_RINGER_MODE_CHANGED_ACTION";

    
The new ringer mode.

See Also:
/**
     * The new ringer mode.
     *
     * @see #RINGER_MODE_CHANGED_ACTION
     * @see #RINGER_MODE_NORMAL
     * @see #RINGER_MODE_SILENT
     * @see #RINGER_MODE_VIBRATE
     */
    public static final String EXTRA_RINGER_MODE = "android.media.EXTRA_RINGER_MODE";

    
Broadcast intent action indicating that the vibrate setting has
changed. Includes the vibrate type and its new setting.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode and listen to RINGER_MODE_CHANGED_ACTION instead.
/**
     * Broadcast intent action indicating that the vibrate setting has
     * changed. Includes the vibrate type and its new setting.
     *
     * @see #EXTRA_VIBRATE_TYPE
     * @see #EXTRA_VIBRATE_SETTING
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode and listen to {@link #RINGER_MODE_CHANGED_ACTION} instead.
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String VIBRATE_SETTING_CHANGED_ACTION =
        "android.media.VIBRATE_SETTING_CHANGED";

    
See Also:
@hideBroadcast intent when the volume for a particular stream type changes.
Includes the stream, the new volume and previous volumes.
Notes:
 - for internal platform use only, do not make public,
 - never used for "remote" volume changes
/**
     * @hide Broadcast intent when the volume for a particular stream type changes.
     * Includes the stream, the new volume and previous volumes.
     * Notes:
     *  - for internal platform use only, do not make public,
     *  - never used for "remote" volume changes
     *
     * @see #EXTRA_VOLUME_STREAM_TYPE
     * @see #EXTRA_VOLUME_STREAM_VALUE
     * @see #EXTRA_PREV_VOLUME_STREAM_VALUE
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String VOLUME_CHANGED_ACTION = "android.media.VOLUME_CHANGED_ACTION";

    
See Also:
@hideBroadcast intent when the devices for a particular stream type changes.
Includes the stream, the new devices and previous devices.
Notes:
 - for internal platform use only, do not make public,
 - never used for "remote" volume changes
/**
     * @hide Broadcast intent when the devices for a particular stream type changes.
     * Includes the stream, the new devices and previous devices.
     * Notes:
     *  - for internal platform use only, do not make public,
     *  - never used for "remote" volume changes
     *
     * @see #EXTRA_VOLUME_STREAM_TYPE
     * @see #EXTRA_VOLUME_STREAM_DEVICES
     * @see #EXTRA_PREV_VOLUME_STREAM_DEVICES
     * @see #getDevicesForStream
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String STREAM_DEVICES_CHANGED_ACTION =
        "android.media.STREAM_DEVICES_CHANGED_ACTION";

    
See Also:
@hideBroadcast intent when a stream mute state changes.
Includes the stream that changed and the new mute state
/**
     * @hide Broadcast intent when a stream mute state changes.
     * Includes the stream that changed and the new mute state
     *
     * @see #EXTRA_VOLUME_STREAM_TYPE
     * @see #EXTRA_STREAM_VOLUME_MUTED
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String STREAM_MUTE_CHANGED_ACTION =
        "android.media.STREAM_MUTE_CHANGED_ACTION";

    
See Also:
@hideBroadcast intent when the master mute state changes.
Includes the the new volume
/**
     * @hide Broadcast intent when the master mute state changes.
     * Includes the the new volume
     *
     * @see #EXTRA_MASTER_VOLUME_MUTED
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String MASTER_MUTE_CHANGED_ACTION =
        "android.media.MASTER_MUTE_CHANGED_ACTION";

    
The new vibrate setting for a particular type.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode and listen to RINGER_MODE_CHANGED_ACTION instead.
/**
     * The new vibrate setting for a particular type.
     *
     * @see #VIBRATE_SETTING_CHANGED_ACTION
     * @see #EXTRA_VIBRATE_TYPE
     * @see #VIBRATE_SETTING_ON
     * @see #VIBRATE_SETTING_OFF
     * @see #VIBRATE_SETTING_ONLY_SILENT
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode and listen to {@link #RINGER_MODE_CHANGED_ACTION} instead.
     */
    public static final String EXTRA_VIBRATE_SETTING = "android.media.EXTRA_VIBRATE_SETTING";

    
The vibrate type whose setting has changed.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode and listen to RINGER_MODE_CHANGED_ACTION instead.
/**
     * The vibrate type whose setting has changed.
     *
     * @see #VIBRATE_SETTING_CHANGED_ACTION
     * @see #VIBRATE_TYPE_NOTIFICATION
     * @see #VIBRATE_TYPE_RINGER
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode and listen to {@link #RINGER_MODE_CHANGED_ACTION} instead.
     */
    public static final String EXTRA_VIBRATE_TYPE = "android.media.EXTRA_VIBRATE_TYPE";

    
@hideThe stream type for the volume changed intent.
/**
     * @hide The stream type for the volume changed intent.
     */
    public static final String EXTRA_VOLUME_STREAM_TYPE = "android.media.EXTRA_VOLUME_STREAM_TYPE";

    
@hide The stream type alias for the volume changed intent. For instance the intent may indicate a change of the STREAM_NOTIFICATION stream type (as indicated by the EXTRA_VOLUME_STREAM_TYPE extra), but this is also reflected by a change of the volume of its alias, STREAM_RING on some devices, STREAM_MUSIC on others (e.g. a television).
/**
     * @hide
     * The stream type alias for the volume changed intent.
     * For instance the intent may indicate a change of the {@link #STREAM_NOTIFICATION} stream
     * type (as indicated by the {@link #EXTRA_VOLUME_STREAM_TYPE} extra), but this is also
     * reflected by a change of the volume of its alias, {@link #STREAM_RING} on some devices,
     * {@link #STREAM_MUSIC} on others (e.g. a television).
     */
    public static final String EXTRA_VOLUME_STREAM_TYPE_ALIAS =
            "android.media.EXTRA_VOLUME_STREAM_TYPE_ALIAS";

    
@hideThe volume associated with the stream for the volume changed intent.
/**
     * @hide The volume associated with the stream for the volume changed intent.
     */
    public static final String EXTRA_VOLUME_STREAM_VALUE =
        "android.media.EXTRA_VOLUME_STREAM_VALUE";

    
@hideThe previous volume associated with the stream for the volume changed intent.
/**
     * @hide The previous volume associated with the stream for the volume changed intent.
     */
    public static final String EXTRA_PREV_VOLUME_STREAM_VALUE =
        "android.media.EXTRA_PREV_VOLUME_STREAM_VALUE";

    
@hideThe devices associated with the stream for the stream devices changed intent.
/**
     * @hide The devices associated with the stream for the stream devices changed intent.
     */
    public static final String EXTRA_VOLUME_STREAM_DEVICES =
        "android.media.EXTRA_VOLUME_STREAM_DEVICES";

    
@hideThe previous devices associated with the stream for the stream devices changed intent.
/**
     * @hide The previous devices associated with the stream for the stream devices changed intent.
     */
    public static final String EXTRA_PREV_VOLUME_STREAM_DEVICES =
        "android.media.EXTRA_PREV_VOLUME_STREAM_DEVICES";

    
@hideThe new master volume mute state for the master mute changed intent.
Value is boolean
/**
     * @hide The new master volume mute state for the master mute changed intent.
     * Value is boolean
     */
    public static final String EXTRA_MASTER_VOLUME_MUTED =
        "android.media.EXTRA_MASTER_VOLUME_MUTED";

    
@hideThe new stream volume mute state for the stream mute changed intent.
Value is boolean
/**
     * @hide The new stream volume mute state for the stream mute changed intent.
     * Value is boolean
     */
    public static final String EXTRA_STREAM_VOLUME_MUTED =
        "android.media.EXTRA_STREAM_VOLUME_MUTED";

    
Broadcast Action: Wired Headset plugged in or unplugged.
You cannot receive this through components declared in manifests, only by explicitly registering for it with 
Context.registerReceiver(). 
The intent will have the following extra values:

    
  
  • state - 0 for unplugged, 1 for plugged. 
    • 
  
  • name - Headset type, human readable string 
    • 
  
  • microphone - 1 if headset has a microphone, 0 otherwise 
    • 




/**
     * Broadcast Action: Wired Headset plugged in or unplugged.
     *
     * You <em>cannot</em> receive this through components declared
     * in manifests, only by explicitly registering for it with
     * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)
     * Context.registerReceiver()}.
     *
     * <p>The intent will have the following extra values:
     * <ul>
     *   <li><em>state</em> - 0 for unplugged, 1 for plugged. </li>
     *   <li><em>name</em> - Headset type, human readable string </li>
     *   <li><em>microphone</em> - 1 if headset has a microphone, 0 otherwise </li>
     * </ul>
     * </ul>
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_HEADSET_PLUG =
            "android.intent.action.HEADSET_PLUG";

    
Broadcast Action: A sticky broadcast indicating an HDMI cable was plugged or unplugged. The intent will have the following extra values: EXTRA_AUDIO_PLUG_STATE, EXTRA_MAX_CHANNEL_COUNT, EXTRA_ENCODINGS. 
It can only be received by explicitly registering for it with Context.registerReceiver(BroadcastReceiver, IntentFilter). 
/**
     * Broadcast Action: A sticky broadcast indicating an HDMI cable was plugged or unplugged.
     *
     * The intent will have the following extra values: {@link #EXTRA_AUDIO_PLUG_STATE},
     * {@link #EXTRA_MAX_CHANNEL_COUNT}, {@link #EXTRA_ENCODINGS}.
     * <p>It can only be received by explicitly registering for it with
     * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)}.
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_HDMI_AUDIO_PLUG =
            "android.media.action.HDMI_AUDIO_PLUG";

    
Extra used in ACTION_HDMI_AUDIO_PLUG to communicate whether HDMI is plugged in or unplugged. An integer value of 1 indicates a plugged-in state, 0 is unplugged. 
/**
     * Extra used in {@link #ACTION_HDMI_AUDIO_PLUG} to communicate whether HDMI is plugged in
     * or unplugged.
     * An integer value of 1 indicates a plugged-in state, 0 is unplugged.
     */
    public static final String EXTRA_AUDIO_PLUG_STATE = "android.media.extra.AUDIO_PLUG_STATE";

    
Extra used in ACTION_HDMI_AUDIO_PLUG to define the maximum number of channels supported by the HDMI device. The corresponding integer value is only available when the device is plugged in (as expressed by EXTRA_AUDIO_PLUG_STATE). 
/**
     * Extra used in {@link #ACTION_HDMI_AUDIO_PLUG} to define the maximum number of channels
     * supported by the HDMI device.
     * The corresponding integer value is only available when the device is plugged in (as expressed
     * by {@link #EXTRA_AUDIO_PLUG_STATE}).
     */
    public static final String EXTRA_MAX_CHANNEL_COUNT = "android.media.extra.MAX_CHANNEL_COUNT";

    
Extra used in ACTION_HDMI_AUDIO_PLUG to define the audio encodings supported by the connected HDMI device. The corresponding array of encoding values is only available when the device is plugged in (as expressed by EXTRA_AUDIO_PLUG_STATE). Encoding values are defined in AudioFormat (for instance see AudioFormat.ENCODING_PCM_16BIT). Use Intent.getIntArrayExtra(String) to retrieve the encoding values. 
/**
     * Extra used in {@link #ACTION_HDMI_AUDIO_PLUG} to define the audio encodings supported by
     * the connected HDMI device.
     * The corresponding array of encoding values is only available when the device is plugged in
     * (as expressed by {@link #EXTRA_AUDIO_PLUG_STATE}). Encoding values are defined in
     * {@link AudioFormat} (for instance see {@link AudioFormat#ENCODING_PCM_16BIT}). Use
     * {@link android.content.Intent#getIntArrayExtra(String)} to retrieve the encoding values.
     */
    public static final String EXTRA_ENCODINGS = "android.media.extra.ENCODINGS";

    
Used to identify the volume of audio streams for phone calls 
/** Used to identify the volume of audio streams for phone calls */
    public static final int STREAM_VOICE_CALL = AudioSystem.STREAM_VOICE_CALL;
    
Used to identify the volume of audio streams for system sounds 
/** Used to identify the volume of audio streams for system sounds */
    public static final int STREAM_SYSTEM = AudioSystem.STREAM_SYSTEM;
    
Used to identify the volume of audio streams for the phone ring 
/** Used to identify the volume of audio streams for the phone ring */
    public static final int STREAM_RING = AudioSystem.STREAM_RING;
    
Used to identify the volume of audio streams for music playback 
/** Used to identify the volume of audio streams for music playback */
    public static final int STREAM_MUSIC = AudioSystem.STREAM_MUSIC;
    
Used to identify the volume of audio streams for alarms 
/** Used to identify the volume of audio streams for alarms */
    public static final int STREAM_ALARM = AudioSystem.STREAM_ALARM;
    
Used to identify the volume of audio streams for notifications 
/** Used to identify the volume of audio streams for notifications */
    public static final int STREAM_NOTIFICATION = AudioSystem.STREAM_NOTIFICATION;
    
@hideUsed to identify the volume of audio streams for phone calls when connected
       to bluetooth
/** @hide Used to identify the volume of audio streams for phone calls when connected
     *        to bluetooth */
    public static final int STREAM_BLUETOOTH_SCO = AudioSystem.STREAM_BLUETOOTH_SCO;
    
@hideUsed to identify the volume of audio streams for enforced system sounds
       in certain countries (e.g camera in Japan)
/** @hide Used to identify the volume of audio streams for enforced system sounds
     *        in certain countries (e.g camera in Japan) */
    public static final int STREAM_SYSTEM_ENFORCED = AudioSystem.STREAM_SYSTEM_ENFORCED;
    
Used to identify the volume of audio streams for DTMF Tones 
/** Used to identify the volume of audio streams for DTMF Tones */
    public static final int STREAM_DTMF = AudioSystem.STREAM_DTMF;
    
@hideUsed to identify the volume of audio streams exclusively transmitted through the
       speaker (TTS) of the device
/** @hide Used to identify the volume of audio streams exclusively transmitted through the
     *        speaker (TTS) of the device */
    public static final int STREAM_TTS = AudioSystem.STREAM_TTS;
    
Used to identify the volume of audio streams for accessibility prompts 
/** Used to identify the volume of audio streams for accessibility prompts */
    public static final int STREAM_ACCESSIBILITY = AudioSystem.STREAM_ACCESSIBILITY;

    /** Number of audio streams */
    
Deprecated:Do not iterate on volume stream type values.
/**
     * @deprecated Do not iterate on volume stream type values.
     */
    @Deprecated public static final int NUM_STREAMS = AudioSystem.NUM_STREAMS;

    
Increase the ringer volume.

See Also:
/**
     * Increase the ringer volume.
     *
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     */
    public static final int ADJUST_RAISE = 1;

    
Decrease the ringer volume.

See Also:
/**
     * Decrease the ringer volume.
     *
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     */
    public static final int ADJUST_LOWER = -1;

    
Maintain the previous ringer volume. This may be useful when needing to
show the volume toast without actually modifying the volume.

See Also:
/**
     * Maintain the previous ringer volume. This may be useful when needing to
     * show the volume toast without actually modifying the volume.
     *
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     */
    public static final int ADJUST_SAME = 0;

    
Mute the volume. Has no effect if the stream is already muted.

See Also:
/**
     * Mute the volume. Has no effect if the stream is already muted.
     *
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     */
    public static final int ADJUST_MUTE = -100;

    
Unmute the volume. Has no effect if the stream is not muted.

See Also:
/**
     * Unmute the volume. Has no effect if the stream is not muted.
     *
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     */
    public static final int ADJUST_UNMUTE = 100;

    
Toggle the mute state. If muted the stream will be unmuted. If not muted
the stream will be muted.

See Also:
/**
     * Toggle the mute state. If muted the stream will be unmuted. If not muted
     * the stream will be muted.
     *
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     */
    public static final int ADJUST_TOGGLE_MUTE = 101;

    
@hide
/** @hide */
    @IntDef(flag = false, prefix = "ADJUST", value = {
            ADJUST_RAISE,
            ADJUST_LOWER,
            ADJUST_SAME,
            ADJUST_MUTE,
            ADJUST_UNMUTE,
            ADJUST_TOGGLE_MUTE }
            )
    @Retention(RetentionPolicy.SOURCE)
    public @interface VolumeAdjustment {}

    
@hide
/** @hide */
    public static final String adjustToString(int adj) {
        switch (adj) {
            case ADJUST_RAISE: return "ADJUST_RAISE";
            case ADJUST_LOWER: return "ADJUST_LOWER";
            case ADJUST_SAME: return "ADJUST_SAME";
            case ADJUST_MUTE: return "ADJUST_MUTE";
            case ADJUST_UNMUTE: return "ADJUST_UNMUTE";
            case ADJUST_TOGGLE_MUTE: return "ADJUST_TOGGLE_MUTE";
            default: return new StringBuilder("unknown adjust mode ").append(adj).toString();
        }
    }

    // Flags should be powers of 2!

    
Show a toast containing the current volume.

See Also:
/**
     * Show a toast containing the current volume.
     *
     * @see #adjustStreamVolume(int, int, int)
     * @see #adjustVolume(int, int)
     * @see #setStreamVolume(int, int, int)
     * @see #setRingerMode(int)
     */
    public static final int FLAG_SHOW_UI = 1 << 0;

    
Whether to include ringer modes as possible options when changing volume. For example, if true and volume level is 0 and the volume is adjusted with ADJUST_LOWER, then the ringer mode may switch the silent or vibrate mode. 

By default this is on for the ring stream. If this flag is included,
this behavior will be present regardless of the stream type being
affected by the ringer mode.

See Also:
/**
     * Whether to include ringer modes as possible options when changing volume.
     * For example, if true and volume level is 0 and the volume is adjusted
     * with {@link #ADJUST_LOWER}, then the ringer mode may switch the silent or
     * vibrate mode.
     * <p>
     * By default this is on for the ring stream. If this flag is included,
     * this behavior will be present regardless of the stream type being
     * affected by the ringer mode.
     *
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     */
    public static final int FLAG_ALLOW_RINGER_MODES = 1 << 1;

    
Whether to play a sound when changing the volume.

 If this is given to adjustVolume(int, int) or adjustSuggestedStreamVolume(int, int, int), it may be ignored in some cases (for example, the decided stream type is not STREAM_RING, or the volume is being adjusted downward). 
See Also:
/**
     * Whether to play a sound when changing the volume.
     * <p>
     * If this is given to {@link #adjustVolume(int, int)} or
     * {@link #adjustSuggestedStreamVolume(int, int, int)}, it may be ignored
     * in some cases (for example, the decided stream type is not
     * {@link AudioManager#STREAM_RING}, or the volume is being adjusted
     * downward).
     *
     * @see #adjustStreamVolume(int, int, int)
     * @see #adjustVolume(int, int)
     * @see #setStreamVolume(int, int, int)
     */
    public static final int FLAG_PLAY_SOUND = 1 << 2;

    
Removes any sounds/vibrate that may be in the queue, or are playing (related to
changing volume).

/**
     * Removes any sounds/vibrate that may be in the queue, or are playing (related to
     * changing volume).
     */
    public static final int FLAG_REMOVE_SOUND_AND_VIBRATE = 1 << 3;

    
Whether to vibrate if going into the vibrate ringer mode.

/**
     * Whether to vibrate if going into the vibrate ringer mode.
     */
    public static final int FLAG_VIBRATE = 1 << 4;

    
Indicates to VolumePanel that the volume slider should be disabled as user
cannot change the stream volume

@hide
/**
     * Indicates to VolumePanel that the volume slider should be disabled as user
     * cannot change the stream volume
     * @hide
     */
    public static final int FLAG_FIXED_VOLUME = 1 << 5;

    
Indicates the volume set/adjust call is for Bluetooth absolute volume

@hide
/**
     * Indicates the volume set/adjust call is for Bluetooth absolute volume
     * @hide
     */
    public static final int FLAG_BLUETOOTH_ABS_VOLUME = 1 << 6;

    
Adjusting the volume was prevented due to silent mode, display a hint in the UI.

@hide
/**
     * Adjusting the volume was prevented due to silent mode, display a hint in the UI.
     * @hide
     */
    public static final int FLAG_SHOW_SILENT_HINT = 1 << 7;

    
Indicates the volume call is for Hdmi Cec system audio volume

@hide
/**
     * Indicates the volume call is for Hdmi Cec system audio volume
     * @hide
     */
    public static final int FLAG_HDMI_SYSTEM_AUDIO_VOLUME = 1 << 8;

    
Indicates that this should only be handled if media is actively playing.

@hide
/**
     * Indicates that this should only be handled if media is actively playing.
     * @hide
     */
    public static final int FLAG_ACTIVE_MEDIA_ONLY = 1 << 9;

    
Like FLAG_SHOW_UI, but only dialog warnings and confirmations, no sliders.

@hide
/**
     * Like FLAG_SHOW_UI, but only dialog warnings and confirmations, no sliders.
     * @hide
     */
    public static final int FLAG_SHOW_UI_WARNINGS = 1 << 10;

    
Adjusting the volume down from vibrated was prevented, display a hint in the UI.

@hide
/**
     * Adjusting the volume down from vibrated was prevented, display a hint in the UI.
     * @hide
     */
    public static final int FLAG_SHOW_VIBRATE_HINT = 1 << 11;

    
Adjusting the volume due to a hardware key press.

@hide
/**
     * Adjusting the volume due to a hardware key press.
     * @hide
     */
    public static final int FLAG_FROM_KEY = 1 << 12;

    private static final String[] FLAG_NAMES = {
        "FLAG_SHOW_UI",
        "FLAG_ALLOW_RINGER_MODES",
        "FLAG_PLAY_SOUND",
        "FLAG_REMOVE_SOUND_AND_VIBRATE",
        "FLAG_VIBRATE",
        "FLAG_FIXED_VOLUME",
        "FLAG_BLUETOOTH_ABS_VOLUME",
        "FLAG_SHOW_SILENT_HINT",
        "FLAG_HDMI_SYSTEM_AUDIO_VOLUME",
        "FLAG_ACTIVE_MEDIA_ONLY",
        "FLAG_SHOW_UI_WARNINGS",
        "FLAG_SHOW_VIBRATE_HINT",
        "FLAG_FROM_KEY",
    };

    
@hide
/** @hide */
    public static String flagsToString(int flags) {
        final StringBuilder sb = new StringBuilder();
        for (int i = 0; i < FLAG_NAMES.length; i++) {
            final int flag = 1 << i;
            if ((flags & flag) != 0) {
                if (sb.length() > 0) {
                    sb.append(',');
                }
                sb.append(FLAG_NAMES[i]);
                flags &= ~flag;
            }
        }
        if (flags != 0) {
            if (sb.length() > 0) {
                sb.append(',');
            }
            sb.append(flags);
        }
        return sb.toString();
    }

    
Ringer mode that will be silent and will not vibrate. (This overrides the
vibrate setting.)

See Also:
/**
     * Ringer mode that will be silent and will not vibrate. (This overrides the
     * vibrate setting.)
     *
     * @see #setRingerMode(int)
     * @see #getRingerMode()
     */
    public static final int RINGER_MODE_SILENT = 0;

    
Ringer mode that will be silent and will vibrate. (This will cause the
phone ringer to always vibrate, but the notification vibrate to only
vibrate if set.)

See Also:
/**
     * Ringer mode that will be silent and will vibrate. (This will cause the
     * phone ringer to always vibrate, but the notification vibrate to only
     * vibrate if set.)
     *
     * @see #setRingerMode(int)
     * @see #getRingerMode()
     */
    public static final int RINGER_MODE_VIBRATE = 1;

    
Ringer mode that may be audible and may vibrate. It will be audible if
the volume before changing out of this mode was audible. It will vibrate
if the vibrate setting is on.

See Also:
/**
     * Ringer mode that may be audible and may vibrate. It will be audible if
     * the volume before changing out of this mode was audible. It will vibrate
     * if the vibrate setting is on.
     *
     * @see #setRingerMode(int)
     * @see #getRingerMode()
     */
    public static final int RINGER_MODE_NORMAL = 2;

    
Maximum valid ringer mode value. Values must start from 0 and be contiguous.

@hide
/**
     * Maximum valid ringer mode value. Values must start from 0 and be contiguous.
     * @hide
     */
    public static final int RINGER_MODE_MAX = RINGER_MODE_NORMAL;

    
Vibrate type that corresponds to the ringer.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Vibrate type that corresponds to the ringer.
     *
     * @see #setVibrateSetting(int, int)
     * @see #getVibrateSetting(int)
     * @see #shouldVibrate(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public static final int VIBRATE_TYPE_RINGER = 0;

    
Vibrate type that corresponds to notifications.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Vibrate type that corresponds to notifications.
     *
     * @see #setVibrateSetting(int, int)
     * @see #getVibrateSetting(int)
     * @see #shouldVibrate(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public static final int VIBRATE_TYPE_NOTIFICATION = 1;

    
Vibrate setting that suggests to never vibrate.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Vibrate setting that suggests to never vibrate.
     *
     * @see #setVibrateSetting(int, int)
     * @see #getVibrateSetting(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public static final int VIBRATE_SETTING_OFF = 0;

    
Vibrate setting that suggests to vibrate when possible.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Vibrate setting that suggests to vibrate when possible.
     *
     * @see #setVibrateSetting(int, int)
     * @see #getVibrateSetting(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public static final int VIBRATE_SETTING_ON = 1;

    
Vibrate setting that suggests to only vibrate when in the vibrate ringer
mode.

See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Vibrate setting that suggests to only vibrate when in the vibrate ringer
     * mode.
     *
     * @see #setVibrateSetting(int, int)
     * @see #getVibrateSetting(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public static final int VIBRATE_SETTING_ONLY_SILENT = 2;

    
Suggests using the default stream type. This may not be used in all
places a stream type is needed.

/**
     * Suggests using the default stream type. This may not be used in all
     * places a stream type is needed.
     */
    public static final int USE_DEFAULT_STREAM_TYPE = Integer.MIN_VALUE;

    private static IAudioService sService;

    
@hide
For test purposes only, will throw NPE with some methods that require a Context.
/**
     * @hide
     * For test purposes only, will throw NPE with some methods that require a Context.
     */
    public AudioManager() {
        mUseVolumeKeySounds = true;
        mUseFixedVolume = false;
    }

    
@hide
/**
     * @hide
     */
    public AudioManager(Context context) {
        setContext(context);
        mUseVolumeKeySounds = getContext().getResources().getBoolean(
                com.android.internal.R.bool.config_useVolumeKeySounds);
        mUseFixedVolume = getContext().getResources().getBoolean(
                com.android.internal.R.bool.config_useFixedVolume);
    }

    private Context getContext() {
        if (mApplicationContext == null) {
            setContext(mOriginalContext);
        }
        if (mApplicationContext != null) {
            return mApplicationContext;
        }
        return mOriginalContext;
    }

    private void setContext(Context context) {
        mApplicationContext = context.getApplicationContext();
        if (mApplicationContext != null) {
            mOriginalContext = null;
        } else {
            mOriginalContext = context;
        }
    }

    private static IAudioService getService()
    {
        if (sService != null) {
            return sService;
        }
        IBinder b = ServiceManager.getService(Context.AUDIO_SERVICE);
        sService = IAudioService.Stub.asInterface(b);
        return sService;
    }

    
Sends a simulated key event for a media button. To simulate a key press, you must first send a KeyEvent built with a KeyEvent.ACTION_DOWN action, then another event with the KeyEvent.ACTION_UP action. 
The key event will be sent to the current media key event consumer which registered with registerMediaButtonEventReceiver(PendingIntent). 
Params:
/**
     * Sends a simulated key event for a media button.
     * To simulate a key press, you must first send a KeyEvent built with a
     * {@link KeyEvent#ACTION_DOWN} action, then another event with the {@link KeyEvent#ACTION_UP}
     * action.
     * <p>The key event will be sent to the current media key event consumer which registered with
     * {@link AudioManager#registerMediaButtonEventReceiver(PendingIntent)}.
     * @param keyEvent a {@link KeyEvent} instance whose key code is one of
     *     {@link KeyEvent#KEYCODE_MUTE},
     *     {@link KeyEvent#KEYCODE_HEADSETHOOK},
     *     {@link KeyEvent#KEYCODE_MEDIA_PLAY},
     *     {@link KeyEvent#KEYCODE_MEDIA_PAUSE},
     *     {@link KeyEvent#KEYCODE_MEDIA_PLAY_PAUSE},
     *     {@link KeyEvent#KEYCODE_MEDIA_STOP},
     *     {@link KeyEvent#KEYCODE_MEDIA_NEXT},
     *     {@link KeyEvent#KEYCODE_MEDIA_PREVIOUS},
     *     {@link KeyEvent#KEYCODE_MEDIA_REWIND},
     *     {@link KeyEvent#KEYCODE_MEDIA_RECORD},
     *     {@link KeyEvent#KEYCODE_MEDIA_FAST_FORWARD},
     *     {@link KeyEvent#KEYCODE_MEDIA_CLOSE},
     *     {@link KeyEvent#KEYCODE_MEDIA_EJECT},
     *     or {@link KeyEvent#KEYCODE_MEDIA_AUDIO_TRACK}.
     */
    public void dispatchMediaKeyEvent(KeyEvent keyEvent) {
        MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
        helper.sendMediaButtonEvent(keyEvent, false);
    }

    
@hide
/**
     * @hide
     */
    public void preDispatchKeyEvent(KeyEvent event, int stream) {
        /*
         * If the user hits another key within the play sound delay, then
         * cancel the sound
         */
        int keyCode = event.getKeyCode();
        if (keyCode != KeyEvent.KEYCODE_VOLUME_DOWN && keyCode != KeyEvent.KEYCODE_VOLUME_UP
                && keyCode != KeyEvent.KEYCODE_VOLUME_MUTE
                && mVolumeKeyUpTime + AudioSystem.PLAY_SOUND_DELAY > SystemClock.uptimeMillis()) {
            /*
             * The user has hit another key during the delay (e.g., 300ms)
             * since the last volume key up, so cancel any sounds.
             */
            adjustSuggestedStreamVolume(ADJUST_SAME,
                    stream, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
        }
    }

    
Indicates if the device implements a fixed volume policy.

Some devices may not have volume control and may operate at a fixed volume,
and may not enable muting or changing the volume of audio streams.
This method will return true on such devices.

The following APIs have no effect when volume is fixed:



/**
     * Indicates if the device implements a fixed volume policy.
     * <p>Some devices may not have volume control and may operate at a fixed volume,
     * and may not enable muting or changing the volume of audio streams.
     * This method will return true on such devices.
     * <p>The following APIs have no effect when volume is fixed:
     * <ul>
     *   <li> {@link #adjustVolume(int, int)}
     *   <li> {@link #adjustSuggestedStreamVolume(int, int, int)}
     *   <li> {@link #adjustStreamVolume(int, int, int)}
     *   <li> {@link #setStreamVolume(int, int, int)}
     *   <li> {@link #setRingerMode(int)}
     *   <li> {@link #setStreamSolo(int, boolean)}
     *   <li> {@link #setStreamMute(int, boolean)}
     * </ul>
     */
    public boolean isVolumeFixed() {
        return mUseFixedVolume;
    }

    
Adjusts the volume of a particular stream by one step in a direction.


This method should only be used by applications that replace the platform-wide
management of audio settings or the main telephony application.

Params:
See Also:
/**
     * Adjusts the volume of a particular stream by one step in a direction.
     * <p>
     * This method should only be used by applications that replace the platform-wide
     * management of audio settings or the main telephony application.
     *
     * @param streamType The stream type to adjust. One of {@link #STREAM_VOICE_CALL},
     * {@link #STREAM_SYSTEM}, {@link #STREAM_RING}, {@link #STREAM_MUSIC},
     * {@link #STREAM_ALARM} or {@link #STREAM_ACCESSIBILITY}.
     * @param direction The direction to adjust the volume. One of
     *            {@link #ADJUST_LOWER}, {@link #ADJUST_RAISE}, or
     *            {@link #ADJUST_SAME}.
     * @param flags One or more flags.
     * @see #adjustVolume(int, int)
     * @see #setStreamVolume(int, int, int)
     */
    public void adjustStreamVolume(int streamType, int direction, int flags) {
        final IAudioService service = getService();
        try {
            service.adjustStreamVolume(streamType, direction, flags,
                    getContext().getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Adjusts the volume of the most relevant stream. For example, if a call is
active, it will have the highest priority regardless of if the in-call
screen is showing. Another example, if music is playing in the background
and a call is not active, the music stream will be adjusted.


This method should only be used by applications that replace the
platform-wide management of audio settings or the main telephony
application.

 This method has no effect if the device implements a fixed volume policy as indicated by isVolumeFixed(). 
Params:
See Also:
/**
     * Adjusts the volume of the most relevant stream. For example, if a call is
     * active, it will have the highest priority regardless of if the in-call
     * screen is showing. Another example, if music is playing in the background
     * and a call is not active, the music stream will be adjusted.
     * <p>
     * This method should only be used by applications that replace the
     * platform-wide management of audio settings or the main telephony
     * application.
     * <p>
     * This method has no effect if the device implements a fixed volume policy
     * as indicated by {@link #isVolumeFixed()}.
     *
     * @param direction The direction to adjust the volume. One of
     *            {@link #ADJUST_LOWER}, {@link #ADJUST_RAISE},
     *            {@link #ADJUST_SAME}, {@link #ADJUST_MUTE},
     *            {@link #ADJUST_UNMUTE}, or {@link #ADJUST_TOGGLE_MUTE}.
     * @param flags One or more flags.
     * @see #adjustSuggestedStreamVolume(int, int, int)
     * @see #adjustStreamVolume(int, int, int)
     * @see #setStreamVolume(int, int, int)
     * @see #isVolumeFixed()
     */
    public void adjustVolume(int direction, int flags) {
        MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
        helper.sendAdjustVolumeBy(USE_DEFAULT_STREAM_TYPE, direction, flags);
    }

    
Adjusts the volume of the most relevant stream, or the given fallback
stream.


This method should only be used by applications that replace the
platform-wide management of audio settings or the main telephony
application.

 This method has no effect if the device implements a fixed volume policy as indicated by isVolumeFixed(). 
Params:
See Also:
/**
     * Adjusts the volume of the most relevant stream, or the given fallback
     * stream.
     * <p>
     * This method should only be used by applications that replace the
     * platform-wide management of audio settings or the main telephony
     * application.
     * <p>
     * This method has no effect if the device implements a fixed volume policy
     * as indicated by {@link #isVolumeFixed()}.
     *
     * @param direction The direction to adjust the volume. One of
     *            {@link #ADJUST_LOWER}, {@link #ADJUST_RAISE},
     *            {@link #ADJUST_SAME}, {@link #ADJUST_MUTE},
     *            {@link #ADJUST_UNMUTE}, or {@link #ADJUST_TOGGLE_MUTE}.
     * @param suggestedStreamType The stream type that will be used if there
     *            isn't a relevant stream. {@link #USE_DEFAULT_STREAM_TYPE} is
     *            valid here.
     * @param flags One or more flags.
     * @see #adjustVolume(int, int)
     * @see #adjustStreamVolume(int, int, int)
     * @see #setStreamVolume(int, int, int)
     * @see #isVolumeFixed()
     */
    public void adjustSuggestedStreamVolume(int direction, int suggestedStreamType, int flags) {
        MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
        helper.sendAdjustVolumeBy(suggestedStreamType, direction, flags);
    }

    
@hide
/** @hide */
    public void setMasterMute(boolean mute, int flags) {
        final IAudioService service = getService();
        try {
            service.setMasterMute(mute, flags, getContext().getOpPackageName(),
                    UserHandle.getCallingUserId());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns the current ringtone mode.

See Also:
Returns:The current ringtone mode, one of RINGER_MODE_NORMAL, RINGER_MODE_SILENT, or RINGER_MODE_VIBRATE.
/**
     * Returns the current ringtone mode.
     *
     * @return The current ringtone mode, one of {@link #RINGER_MODE_NORMAL},
     *         {@link #RINGER_MODE_SILENT}, or {@link #RINGER_MODE_VIBRATE}.
     * @see #setRingerMode(int)
     */
    public int getRingerMode() {
        final IAudioService service = getService();
        try {
            return service.getRingerModeExternal();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Checks valid ringer mode values.

See Also:
Returns:true if the ringer mode indicated is valid, false otherwise.
@hide
/**
     * Checks valid ringer mode values.
     *
     * @return true if the ringer mode indicated is valid, false otherwise.
     *
     * @see #setRingerMode(int)
     * @hide
     */
    public static boolean isValidRingerMode(int ringerMode) {
        if (ringerMode < 0 || ringerMode > RINGER_MODE_MAX) {
            return false;
        }
        final IAudioService service = getService();
        try {
            return service.isValidRingerMode(ringerMode);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns the maximum volume index for a particular stream.

Params:
  • streamType – The stream type whose maximum volume index is returned.
See Also:
Returns:The maximum valid volume index for the stream.
/**
     * Returns the maximum volume index for a particular stream.
     *
     * @param streamType The stream type whose maximum volume index is returned.
     * @return The maximum valid volume index for the stream.
     * @see #getStreamVolume(int)
     */
    public int getStreamMaxVolume(int streamType) {
        final IAudioService service = getService();
        try {
            return service.getStreamMaxVolume(streamType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns the minimum volume index for a particular stream.

Params:
See Also:
Returns:The minimum valid volume index for the stream.
/**
     * Returns the minimum volume index for a particular stream.
     * @param streamType The stream type whose minimum volume index is returned. Must be one of
     *     {@link #STREAM_VOICE_CALL}, {@link #STREAM_SYSTEM},
     *     {@link #STREAM_RING}, {@link #STREAM_MUSIC}, {@link #STREAM_ALARM},
     *     {@link #STREAM_NOTIFICATION}, {@link #STREAM_DTMF} or {@link #STREAM_ACCESSIBILITY}.
     * @return The minimum valid volume index for the stream.
     * @see #getStreamVolume(int)
     */
    public int getStreamMinVolume(int streamType) {
        if (!isPublicStreamType(streamType)) {
            throw new IllegalArgumentException("Invalid stream type " + streamType);
        }
        return getStreamMinVolumeInt(streamType);
    }

    
Params:
  • streamType – The stream type whose minimum volume index is returned.
See Also:
@hide Same as getStreamMinVolume(int) but without the check on the public stream type.
Returns:The minimum valid volume index for the stream.
/**
     * @hide
     * Same as {@link #getStreamMinVolume(int)} but without the check on the public stream type.
     * @param streamType The stream type whose minimum volume index is returned.
     * @return The minimum valid volume index for the stream.
     * @see #getStreamVolume(int)
     */
    public int getStreamMinVolumeInt(int streamType) {
        final IAudioService service = getService();
        try {
            return service.getStreamMinVolume(streamType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns the current volume index for a particular stream.

Params:
  • streamType – The stream type whose volume index is returned.
See Also:
Returns:The current volume index for the stream.
/**
     * Returns the current volume index for a particular stream.
     *
     * @param streamType The stream type whose volume index is returned.
     * @return The current volume index for the stream.
     * @see #getStreamMaxVolume(int)
     * @see #setStreamVolume(int, int, int)
     */
    public int getStreamVolume(int streamType) {
        final IAudioService service = getService();
        try {
            return service.getStreamVolume(streamType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    // keep in sync with frameworks/av/services/audiopolicy/common/include/Volume.h
    private static final float VOLUME_MIN_DB = -758.0f;

    
@hide
/** @hide */
    @IntDef(flag = false, prefix = "STREAM", value = {
            STREAM_VOICE_CALL,
            STREAM_SYSTEM,
            STREAM_RING,
            STREAM_MUSIC,
            STREAM_ALARM,
            STREAM_NOTIFICATION,
            STREAM_DTMF,
            STREAM_ACCESSIBILITY }
    )
    @Retention(RetentionPolicy.SOURCE)
    public @interface PublicStreamTypes {}

    
Returns the volume in dB (decibel) for the given stream type at the given volume index, on
the given type of audio output device.

Params:
  • streamType – stream type for which the volume is queried.
  • index – the volume index for which the volume is queried. The index value must be between the minimum and maximum index values for the given stream type (see getStreamMinVolume(int) and getStreamMaxVolume(int)).
  • deviceType – the type of audio output device for which volume is queried.
Returns:a volume expressed in dB. A negative value indicates the audio signal is attenuated. A typical maximum value at the maximum volume index is 0 dB (no attenuation nor amplification). Muting is reflected by a value of Float.NEGATIVE_INFINITY.
/**
     * Returns the volume in dB (decibel) for the given stream type at the given volume index, on
     * the given type of audio output device.
     * @param streamType stream type for which the volume is queried.
     * @param index the volume index for which the volume is queried. The index value must be
     *     between the minimum and maximum index values for the given stream type (see
     *     {@link #getStreamMinVolume(int)} and {@link #getStreamMaxVolume(int)}).
     * @param deviceType the type of audio output device for which volume is queried.
     * @return a volume expressed in dB.
     *     A negative value indicates the audio signal is attenuated. A typical maximum value
     *     at the maximum volume index is 0 dB (no attenuation nor amplification). Muting is
     *     reflected by a value of {@link Float#NEGATIVE_INFINITY}.
     */
    public float getStreamVolumeDb(@PublicStreamTypes int streamType, int index,
            @AudioDeviceInfo.AudioDeviceTypeOut int deviceType) {
        if (!isPublicStreamType(streamType)) {
            throw new IllegalArgumentException("Invalid stream type " + streamType);
        }
        if (index > getStreamMaxVolume(streamType) || index < getStreamMinVolume(streamType)) {
            throw new IllegalArgumentException("Invalid stream volume index " + index);
        }
        if (!AudioDeviceInfo.isValidAudioDeviceTypeOut(deviceType)) {
            throw new IllegalArgumentException("Invalid audio output device type " + deviceType);
        }
        final float gain = AudioSystem.getStreamVolumeDB(streamType, index,
                AudioDeviceInfo.convertDeviceTypeToInternalDevice(deviceType));
        if (gain <= VOLUME_MIN_DB) {
            return Float.NEGATIVE_INFINITY;
        } else {
            return gain;
        }
    }

    private static boolean isPublicStreamType(int streamType) {
        switch (streamType) {
            case STREAM_VOICE_CALL:
            case STREAM_SYSTEM:
            case STREAM_RING:
            case STREAM_MUSIC:
            case STREAM_ALARM:
            case STREAM_NOTIFICATION:
            case STREAM_DTMF:
            case STREAM_ACCESSIBILITY:
                return true;
            default:
                return false;
        }
    }

    
Get last audible volume before stream was muted.

@hide
/**
     * Get last audible volume before stream was muted.
     *
     * @hide
     */
    public int getLastAudibleStreamVolume(int streamType) {
        final IAudioService service = getService();
        try {
            return service.getLastAudibleStreamVolume(streamType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Get the stream type whose volume is driving the UI sounds volume.
UI sounds are screen lock/unlock, camera shutter, key clicks...
It is assumed that this stream type is also tied to ringer mode changes.

@hide
/**
     * Get the stream type whose volume is driving the UI sounds volume.
     * UI sounds are screen lock/unlock, camera shutter, key clicks...
     * It is assumed that this stream type is also tied to ringer mode changes.
     * @hide
     */
    public int getUiSoundsStreamType() {
        final IAudioService service = getService();
        try {
            return service.getUiSoundsStreamType();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Sets the ringer mode.


Silent mode will mute the volume and will not vibrate. Vibrate mode will
mute the volume and vibrate. Normal mode will be audible and may vibrate
according to user settings.

This method has no effect if the device implements a fixed volume policy as indicated by isVolumeFixed(). * 
From N onward, ringer mode adjustments that would toggle Do Not Disturb are not allowed unless the app has been granted Do Not Disturb Access. See NotificationManager.isNotificationPolicyAccessGranted(). 
Params:
See Also:
/**
     * Sets the ringer mode.
     * <p>
     * Silent mode will mute the volume and will not vibrate. Vibrate mode will
     * mute the volume and vibrate. Normal mode will be audible and may vibrate
     * according to user settings.
     * <p>This method has no effect if the device implements a fixed volume policy
     * as indicated by {@link #isVolumeFixed()}.
     * * <p>From N onward, ringer mode adjustments that would toggle Do Not Disturb are not allowed
     * unless the app has been granted Do Not Disturb Access.
     * See {@link NotificationManager#isNotificationPolicyAccessGranted()}.
     * @param ringerMode The ringer mode, one of {@link #RINGER_MODE_NORMAL},
     *            {@link #RINGER_MODE_SILENT}, or {@link #RINGER_MODE_VIBRATE}.
     * @see #getRingerMode()
     * @see #isVolumeFixed()
     */
    public void setRingerMode(int ringerMode) {
        if (!isValidRingerMode(ringerMode)) {
            return;
        }
        final IAudioService service = getService();
        try {
            service.setRingerModeExternal(ringerMode, getContext().getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Sets the volume index for a particular stream.

This method has no effect if the device implements a fixed volume policy as indicated by isVolumeFixed(). 
From N onward, volume adjustments that would toggle Do Not Disturb are not allowed unless the app has been granted Do Not Disturb Access. See NotificationManager.isNotificationPolicyAccessGranted(). 
Params:
  • streamType – The stream whose volume index should be set.
  • index – The volume index to set. See getStreamMaxVolume(int) for the largest valid value.
  • flags – One or more flags.
See Also:
/**
     * Sets the volume index for a particular stream.
     * <p>This method has no effect if the device implements a fixed volume policy
     * as indicated by {@link #isVolumeFixed()}.
     * <p>From N onward, volume adjustments that would toggle Do Not Disturb are not allowed unless
     * the app has been granted Do Not Disturb Access.
     * See {@link NotificationManager#isNotificationPolicyAccessGranted()}.
     * @param streamType The stream whose volume index should be set.
     * @param index The volume index to set. See
     *            {@link #getStreamMaxVolume(int)} for the largest valid value.
     * @param flags One or more flags.
     * @see #getStreamMaxVolume(int)
     * @see #getStreamVolume(int)
     * @see #isVolumeFixed()
     */
    public void setStreamVolume(int streamType, int index, int flags) {
        final IAudioService service = getService();
        try {
            service.setStreamVolume(streamType, index, flags, getContext().getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Solo or unsolo a particular stream.

 Do not use. This method has been deprecated and is now a no-op. requestAudioFocus should be used for exclusive audio playback. 
Params:
  • streamType – The stream to be soloed/unsoloed.
  • state – The required solo state: true for solo ON, false for solo
           OFF
See Also:
Deprecated:Do not use. If you need exclusive audio playback use requestAudioFocus.
/**
     * Solo or unsolo a particular stream.
     * <p>
     * Do not use. This method has been deprecated and is now a no-op.
     * {@link #requestAudioFocus} should be used for exclusive audio playback.
     *
     * @param streamType The stream to be soloed/unsoloed.
     * @param state The required solo state: true for solo ON, false for solo
     *            OFF
     * @see #isVolumeFixed()
     * @deprecated Do not use. If you need exclusive audio playback use
     *             {@link #requestAudioFocus}.
     */
    @Deprecated
    public void setStreamSolo(int streamType, boolean state) {
        Log.w(TAG, "setStreamSolo has been deprecated. Do not use.");
    }

    
Mute or unmute an audio stream.


This method should only be used by applications that replace the
platform-wide management of audio settings or the main telephony
application.

 This method has no effect if the device implements a fixed volume policy as indicated by isVolumeFixed(). 

This method was deprecated in API level 22. Prior to API level 22 this
method had significantly different behavior and should be used carefully.
The following applies only to pre-22 platforms:

    

  • The mute command is protected against client process death: if a
process with an active mute request on a stream dies, this stream will be
unmuted automatically.
    • 

  • The mute requests for a given stream are cumulative: the AudioManager
can receive several mute requests from one or more clients and the stream
will be unmuted only when the same number of unmute requests are
received.
    • 

  • For a better user experience, applications MUST unmute a muted stream
in onPause() and mute is again in onResume() if appropriate.
    • 



Params:
  • streamType – The stream to be muted/unmuted.
  • state – The required mute state: true for mute ON, false for mute
           OFF
See Also:
Deprecated:Use adjustStreamVolume(int, int, int) with ADJUST_MUTE or ADJUST_UNMUTE instead.
/**
     * Mute or unmute an audio stream.
     * <p>
     * This method should only be used by applications that replace the
     * platform-wide management of audio settings or the main telephony
     * application.
     * <p>
     * This method has no effect if the device implements a fixed volume policy
     * as indicated by {@link #isVolumeFixed()}.
     * <p>
     * This method was deprecated in API level 22. Prior to API level 22 this
     * method had significantly different behavior and should be used carefully.
     * The following applies only to pre-22 platforms:
     * <ul>
     * <li>The mute command is protected against client process death: if a
     * process with an active mute request on a stream dies, this stream will be
     * unmuted automatically.</li>
     * <li>The mute requests for a given stream are cumulative: the AudioManager
     * can receive several mute requests from one or more clients and the stream
     * will be unmuted only when the same number of unmute requests are
     * received.</li>
     * <li>For a better user experience, applications MUST unmute a muted stream
     * in onPause() and mute is again in onResume() if appropriate.</li>
     * </ul>
     *
     * @param streamType The stream to be muted/unmuted.
     * @param state The required mute state: true for mute ON, false for mute
     *            OFF
     * @see #isVolumeFixed()
     * @deprecated Use {@link #adjustStreamVolume(int, int, int)} with
     *             {@link #ADJUST_MUTE} or {@link #ADJUST_UNMUTE} instead.
     */
    @Deprecated
    public void setStreamMute(int streamType, boolean state) {
        Log.w(TAG, "setStreamMute is deprecated. adjustStreamVolume should be used instead.");
        int direction = state ? ADJUST_MUTE : ADJUST_UNMUTE;
        if (streamType == AudioManager.USE_DEFAULT_STREAM_TYPE) {
            adjustSuggestedStreamVolume(direction, streamType, 0);
        } else {
            adjustStreamVolume(streamType, direction, 0);
        }
    }

    
Returns the current mute state for a particular stream.

Params:
  • streamType – The stream to get mute state for.
See Also:
Returns:The mute state for the given stream.
/**
     * Returns the current mute state for a particular stream.
     *
     * @param streamType The stream to get mute state for.
     * @return The mute state for the given stream.
     * @see #adjustStreamVolume(int, int, int)
     */
    public boolean isStreamMute(int streamType) {
        final IAudioService service = getService();
        try {
            return service.isStreamMute(streamType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
get master mute state.

@hide
/**
     * get master mute state.
     *
     * @hide
     */
    public boolean isMasterMute() {
        final IAudioService service = getService();
        try {
            return service.isMasterMute();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
forces the stream controlled by hard volume keys
specifying streamType == -1 releases control to the
logic.

@hide
/**
     * forces the stream controlled by hard volume keys
     * specifying streamType == -1 releases control to the
     * logic.
     *
     * @hide
     */
    public void forceVolumeControlStream(int streamType) {
        final IAudioService service = getService();
        try {
            service.forceVolumeControlStream(streamType, mICallBack);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns whether a particular type should vibrate according to user
settings and the current ringer mode.


This shouldn't be needed by most clients that use notifications to
vibrate. The notification manager will not vibrate if the policy doesn't
allow it, so the client should always set a vibrate pattern and let the
notification manager control whether or not to actually vibrate.

Params:
See Also:
Returns:Whether the type should vibrate at the instant this method is
        called.
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Returns whether a particular type should vibrate according to user
     * settings and the current ringer mode.
     * <p>
     * This shouldn't be needed by most clients that use notifications to
     * vibrate. The notification manager will not vibrate if the policy doesn't
     * allow it, so the client should always set a vibrate pattern and let the
     * notification manager control whether or not to actually vibrate.
     *
     * @param vibrateType The type of vibrate. One of
     *            {@link #VIBRATE_TYPE_NOTIFICATION} or
     *            {@link #VIBRATE_TYPE_RINGER}.
     * @return Whether the type should vibrate at the instant this method is
     *         called.
     * @see #setVibrateSetting(int, int)
     * @see #getVibrateSetting(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public boolean shouldVibrate(int vibrateType) {
        final IAudioService service = getService();
        try {
            return service.shouldVibrate(vibrateType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns whether the user's vibrate setting for a vibrate type.

 This shouldn't be needed by most clients that want to vibrate, instead see shouldVibrate(int). 
Params:
See Also:
Returns:The vibrate setting, one of VIBRATE_SETTING_ON, VIBRATE_SETTING_OFF, or VIBRATE_SETTING_ONLY_SILENT.
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Returns whether the user's vibrate setting for a vibrate type.
     * <p>
     * This shouldn't be needed by most clients that want to vibrate, instead
     * see {@link #shouldVibrate(int)}.
     *
     * @param vibrateType The type of vibrate. One of
     *            {@link #VIBRATE_TYPE_NOTIFICATION} or
     *            {@link #VIBRATE_TYPE_RINGER}.
     * @return The vibrate setting, one of {@link #VIBRATE_SETTING_ON},
     *         {@link #VIBRATE_SETTING_OFF}, or
     *         {@link #VIBRATE_SETTING_ONLY_SILENT}.
     * @see #setVibrateSetting(int, int)
     * @see #shouldVibrate(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public int getVibrateSetting(int vibrateType) {
        final IAudioService service = getService();
        try {
            return service.getVibrateSetting(vibrateType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Sets the setting for when the vibrate type should vibrate.


This method should only be used by applications that replace the platform-wide
management of audio settings or the main telephony application.

Params:
See Also:
Deprecated:Applications should maintain their own vibrate policy based on current ringer mode that can be queried via getRingerMode().
/**
     * Sets the setting for when the vibrate type should vibrate.
     * <p>
     * This method should only be used by applications that replace the platform-wide
     * management of audio settings or the main telephony application.
     *
     * @param vibrateType The type of vibrate. One of
     *            {@link #VIBRATE_TYPE_NOTIFICATION} or
     *            {@link #VIBRATE_TYPE_RINGER}.
     * @param vibrateSetting The vibrate setting, one of
     *            {@link #VIBRATE_SETTING_ON},
     *            {@link #VIBRATE_SETTING_OFF}, or
     *            {@link #VIBRATE_SETTING_ONLY_SILENT}.
     * @see #getVibrateSetting(int)
     * @see #shouldVibrate(int)
     * @deprecated Applications should maintain their own vibrate policy based on
     * current ringer mode that can be queried via {@link #getRingerMode()}.
     */
    public void setVibrateSetting(int vibrateType, int vibrateSetting) {
        final IAudioService service = getService();
        try {
            service.setVibrateSetting(vibrateType, vibrateSetting);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Sets the speakerphone on or off.


This method should only be used by applications that replace the platform-wide
management of audio settings or the main telephony application.

Params:
  • on – set true to turn on speakerphone;
          false to turn it off
/**
     * Sets the speakerphone on or off.
     * <p>
     * This method should only be used by applications that replace the platform-wide
     * management of audio settings or the main telephony application.
     *
     * @param on set <var>true</var> to turn on speakerphone;
     *           <var>false</var> to turn it off
     */
    public void setSpeakerphoneOn(boolean on){
        final IAudioService service = getService();
        try {
            service.setSpeakerphoneOn(on);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Checks whether the speakerphone is on or off.

Returns:true if speakerphone is on, false if it's off
/**
     * Checks whether the speakerphone is on or off.
     *
     * @return true if speakerphone is on, false if it's off
     */
    public boolean isSpeakerphoneOn() {
        final IAudioService service = getService();
        try {
            return service.isSpeakerphoneOn();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
     }

    //====================================================================
    // Offload query
    
Params:
  • format – the audio format (codec, sample rate, channels) being checked.
@hide
Returns whether offloaded playback of an audio format is supported on the device.
Offloaded playback is where the decoding of an audio stream is not competing with other
software resources. In general, it is supported by dedicated hardware, such as audio DSPs.
Returns:true if the given audio format can be offloaded.
/**
     * @hide
     * Returns whether offloaded playback of an audio format is supported on the device.
     * Offloaded playback is where the decoding of an audio stream is not competing with other
     * software resources. In general, it is supported by dedicated hardware, such as audio DSPs.
     * @param format the audio format (codec, sample rate, channels) being checked.
     * @return true if the given audio format can be offloaded.
     */
    public boolean isOffloadedPlaybackSupported(@NonNull AudioFormat format) {
        return AudioSystem.isOffloadSupported(format);
    }

    //====================================================================
    // Bluetooth SCO control
    
Sticky broadcast intent action indicating that the Bluetooth SCO audio connection state has changed. The intent contains on extra EXTRA_SCO_AUDIO_STATE indicating the new state which is either SCO_AUDIO_STATE_DISCONNECTED or SCO_AUDIO_STATE_CONNECTED 
See Also:
Deprecated:Use ACTION_SCO_AUDIO_STATE_UPDATED instead
/**
     * Sticky broadcast intent action indicating that the Bluetooth SCO audio
     * connection state has changed. The intent contains on extra {@link #EXTRA_SCO_AUDIO_STATE}
     * indicating the new state which is either {@link #SCO_AUDIO_STATE_DISCONNECTED}
     * or {@link #SCO_AUDIO_STATE_CONNECTED}
     *
     * @see #startBluetoothSco()
     * @deprecated Use  {@link #ACTION_SCO_AUDIO_STATE_UPDATED} instead
     */
    @Deprecated
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_SCO_AUDIO_STATE_CHANGED =
            "android.media.SCO_AUDIO_STATE_CHANGED";

     
Sticky broadcast intent action indicating that the Bluetooth SCO audio
connection state has been updated.

This intent has two extras:



 EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE can be any of:



See Also:
/**
     * Sticky broadcast intent action indicating that the Bluetooth SCO audio
     * connection state has been updated.
     * <p>This intent has two extras:
     * <ul>
     *   <li> {@link #EXTRA_SCO_AUDIO_STATE} - The new SCO audio state. </li>
     *   <li> {@link #EXTRA_SCO_AUDIO_PREVIOUS_STATE}- The previous SCO audio state. </li>
     * </ul>
     * <p> EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE can be any of:
     * <ul>
     *   <li> {@link #SCO_AUDIO_STATE_DISCONNECTED}, </li>
     *   <li> {@link #SCO_AUDIO_STATE_CONNECTING} or </li>
     *   <li> {@link #SCO_AUDIO_STATE_CONNECTED}, </li>
     * </ul>
     * @see #startBluetoothSco()
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_SCO_AUDIO_STATE_UPDATED =
            "android.media.ACTION_SCO_AUDIO_STATE_UPDATED";

    
Extra for intent ACTION_SCO_AUDIO_STATE_CHANGED or ACTION_SCO_AUDIO_STATE_UPDATED containing the new bluetooth SCO connection state. 
/**
     * Extra for intent {@link #ACTION_SCO_AUDIO_STATE_CHANGED} or
     * {@link #ACTION_SCO_AUDIO_STATE_UPDATED} containing the new bluetooth SCO connection state.
     */
    public static final String EXTRA_SCO_AUDIO_STATE =
            "android.media.extra.SCO_AUDIO_STATE";

    
Extra for intent ACTION_SCO_AUDIO_STATE_UPDATED containing the previous bluetooth SCO connection state. 
/**
     * Extra for intent {@link #ACTION_SCO_AUDIO_STATE_UPDATED} containing the previous
     * bluetooth SCO connection state.
     */
    public static final String EXTRA_SCO_AUDIO_PREVIOUS_STATE =
            "android.media.extra.SCO_AUDIO_PREVIOUS_STATE";

    
Value for extra EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE
indicating that the SCO audio channel is not established

/**
     * Value for extra EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE
     * indicating that the SCO audio channel is not established
     */
    public static final int SCO_AUDIO_STATE_DISCONNECTED = 0;
    
Value for extra EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE indicating that the SCO audio channel is established 
/**
     * Value for extra {@link #EXTRA_SCO_AUDIO_STATE} or {@link #EXTRA_SCO_AUDIO_PREVIOUS_STATE}
     * indicating that the SCO audio channel is established
     */
    public static final int SCO_AUDIO_STATE_CONNECTED = 1;
    
Value for extra EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE
indicating that the SCO audio channel is being established

/**
     * Value for extra EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE
     * indicating that the SCO audio channel is being established
     */
    public static final int SCO_AUDIO_STATE_CONNECTING = 2;
    
Value for extra EXTRA_SCO_AUDIO_STATE indicating that
there was an error trying to obtain the state

/**
     * Value for extra EXTRA_SCO_AUDIO_STATE indicating that
     * there was an error trying to obtain the state
     */
    public static final int SCO_AUDIO_STATE_ERROR = -1;


    
Indicates if current platform supports use of SCO for off call use cases.
Application wanted to use bluetooth SCO audio when the phone is not in call
must first call this method to make sure that the platform supports this
feature.

See Also:
Returns:true if bluetooth SCO can be used for audio when not in call
        false otherwise
/**
     * Indicates if current platform supports use of SCO for off call use cases.
     * Application wanted to use bluetooth SCO audio when the phone is not in call
     * must first call this method to make sure that the platform supports this
     * feature.
     * @return true if bluetooth SCO can be used for audio when not in call
     *         false otherwise
     * @see #startBluetoothSco()
    */
    public boolean isBluetoothScoAvailableOffCall() {
        return getContext().getResources().getBoolean(
               com.android.internal.R.bool.config_bluetooth_sco_off_call);
    }

    
Start bluetooth SCO audio connection.

Requires Permission: MODIFY_AUDIO_SETTINGS.MODIFY_AUDIO_SETTINGS. 
This method can be used by applications wanting to send and received audio
to/from a bluetooth SCO headset while the phone is not in call.

As the SCO connection establishment can take several seconds, applications should not rely on the connection to be available when the method returns but instead register to receive the intent ACTION_SCO_AUDIO_STATE_UPDATED and wait for the state to be SCO_AUDIO_STATE_CONNECTED. 
As the ACTION_SCO_AUDIO_STATE_UPDATED intent is sticky, the application can check the SCO
audio state before calling startBluetoothSco() by reading the intent returned by the receiver
registration. If the state is already CONNECTED, no state change will be received via the
intent after calling startBluetoothSco(). It is however useful to call startBluetoothSco()
so that the connection stays active in case the current initiator stops the connection.

Unless the connection is already active as described above, the state will always
transition from DISCONNECTED to CONNECTING and then either to CONNECTED if the connection
succeeds or back to DISCONNECTED if the connection fails (e.g no headset is connected).

When finished with the SCO connection or if the establishment fails, the application must call stopBluetoothSco() to clear the request and turn down the bluetooth connection. 
Even if a SCO connection is established, the following restrictions apply on audio
output streams so that they can be routed to SCO headset:

    
  
  •  the stream type must be STREAM_VOICE_CALL 
    • 
  
  •  the format must be mono 
    • 
  
  •  the sampling must be 16kHz or 8kHz 
    • 



The following restrictions apply on input streams:

    
  
  •  the format must be mono 
    • 
  
  •  the sampling must be 8kHz 
    • 



Note that the phone application always has the priority on the usage of the SCO
connection for telephony. If this method is called while the phone is in call
it will be ignored. Similarly, if a call is received or sent while an application
is using the SCO connection, the connection will be lost for the application and NOT
returned automatically when the call ends.

NOTE: up to and including API version VERSION_CODES.JELLY_BEAN_MR1, this method initiates a virtual voice call to the bluetooth headset. After API version VERSION_CODES.JELLY_BEAN_MR2 only a raw SCO audio connection is established. 
See Also:
/**
     * Start bluetooth SCO audio connection.
     * <p>Requires Permission:
     *   {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}.
     * <p>This method can be used by applications wanting to send and received audio
     * to/from a bluetooth SCO headset while the phone is not in call.
     * <p>As the SCO connection establishment can take several seconds,
     * applications should not rely on the connection to be available when the method
     * returns but instead register to receive the intent {@link #ACTION_SCO_AUDIO_STATE_UPDATED}
     * and wait for the state to be {@link #SCO_AUDIO_STATE_CONNECTED}.
     * <p>As the ACTION_SCO_AUDIO_STATE_UPDATED intent is sticky, the application can check the SCO
     * audio state before calling startBluetoothSco() by reading the intent returned by the receiver
     * registration. If the state is already CONNECTED, no state change will be received via the
     * intent after calling startBluetoothSco(). It is however useful to call startBluetoothSco()
     * so that the connection stays active in case the current initiator stops the connection.
     * <p>Unless the connection is already active as described above, the state will always
     * transition from DISCONNECTED to CONNECTING and then either to CONNECTED if the connection
     * succeeds or back to DISCONNECTED if the connection fails (e.g no headset is connected).
     * <p>When finished with the SCO connection or if the establishment fails, the application must
     * call {@link #stopBluetoothSco()} to clear the request and turn down the bluetooth connection.
     * <p>Even if a SCO connection is established, the following restrictions apply on audio
     * output streams so that they can be routed to SCO headset:
     * <ul>
     *   <li> the stream type must be {@link #STREAM_VOICE_CALL} </li>
     *   <li> the format must be mono </li>
     *   <li> the sampling must be 16kHz or 8kHz </li>
     * </ul>
     * <p>The following restrictions apply on input streams:
     * <ul>
     *   <li> the format must be mono </li>
     *   <li> the sampling must be 8kHz </li>
     * </ul>
     * <p>Note that the phone application always has the priority on the usage of the SCO
     * connection for telephony. If this method is called while the phone is in call
     * it will be ignored. Similarly, if a call is received or sent while an application
     * is using the SCO connection, the connection will be lost for the application and NOT
     * returned automatically when the call ends.
     * <p>NOTE: up to and including API version
     * {@link android.os.Build.VERSION_CODES#JELLY_BEAN_MR1}, this method initiates a virtual
     * voice call to the bluetooth headset.
     * After API version {@link android.os.Build.VERSION_CODES#JELLY_BEAN_MR2} only a raw SCO audio
     * connection is established.
     * @see #stopBluetoothSco()
     * @see #ACTION_SCO_AUDIO_STATE_UPDATED
     */
    public void startBluetoothSco(){
        final IAudioService service = getService();
        try {
            service.startBluetoothSco(mICallBack,
                    getContext().getApplicationInfo().targetSdkVersion);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
See Also:
@hide
Start bluetooth SCO audio connection in virtual call mode.

Requires Permission: MODIFY_AUDIO_SETTINGS.MODIFY_AUDIO_SETTINGS. 
Similar to startBluetoothSco() with explicit selection of virtual call mode. Telephony and communication applications (VoIP, Video Chat) should preferably select virtual call mode. Applications using voice input for search or commands should first try raw audio connection with startBluetoothSco() and fall back to startBluetoothScoVirtualCall() in case of failure.
/**
     * @hide
     * Start bluetooth SCO audio connection in virtual call mode.
     * <p>Requires Permission:
     *   {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}.
     * <p>Similar to {@link #startBluetoothSco()} with explicit selection of virtual call mode.
     * Telephony and communication applications (VoIP, Video Chat) should preferably select
     * virtual call mode.
     * Applications using voice input for search or commands should first try raw audio connection
     * with {@link #startBluetoothSco()} and fall back to startBluetoothScoVirtualCall() in case of
     * failure.
     * @see #startBluetoothSco()
     * @see #stopBluetoothSco()
     * @see #ACTION_SCO_AUDIO_STATE_UPDATED
     */
    public void startBluetoothScoVirtualCall() {
        final IAudioService service = getService();
        try {
            service.startBluetoothScoVirtualCall(mICallBack);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Stop bluetooth SCO audio connection.

Requires Permission: MODIFY_AUDIO_SETTINGS.MODIFY_AUDIO_SETTINGS. 
This method must be called by applications having requested the use of bluetooth SCO audio with startBluetoothSco() when finished with the SCO connection or if connection fails. 
See Also:
/**
     * Stop bluetooth SCO audio connection.
     * <p>Requires Permission:
     *   {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}.
     * <p>This method must be called by applications having requested the use of
     * bluetooth SCO audio with {@link #startBluetoothSco()} when finished with the SCO
     * connection or if connection fails.
     * @see #startBluetoothSco()
     */
    // Also used for connections started with {@link #startBluetoothScoVirtualCall()}
    public void stopBluetoothSco(){
        final IAudioService service = getService();
        try {
            service.stopBluetoothSco(mICallBack);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Request use of Bluetooth SCO headset for communications.


This method should only be used by applications that replace the platform-wide
management of audio settings or the main telephony application.

Params:
  • on – set true to use bluetooth SCO for communications;
              false to not use bluetooth SCO for communications
/**
     * Request use of Bluetooth SCO headset for communications.
     * <p>
     * This method should only be used by applications that replace the platform-wide
     * management of audio settings or the main telephony application.
     *
     * @param on set <var>true</var> to use bluetooth SCO for communications;
     *               <var>false</var> to not use bluetooth SCO for communications
     */
    public void setBluetoothScoOn(boolean on){
        final IAudioService service = getService();
        try {
            service.setBluetoothScoOn(on);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Checks whether communications use Bluetooth SCO.

Returns:true if SCO is used for communications;
        false if otherwise
/**
     * Checks whether communications use Bluetooth SCO.
     *
     * @return true if SCO is used for communications;
     *         false if otherwise
     */
    public boolean isBluetoothScoOn() {
        final IAudioService service = getService();
        try {
            return service.isBluetoothScoOn();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Params:
  • on – set true to route A2DP audio to/from Bluetooth
          headset; false disable A2DP audio
Deprecated:Do not use.
/**
     * @param on set <var>true</var> to route A2DP audio to/from Bluetooth
     *           headset; <var>false</var> disable A2DP audio
     * @deprecated Do not use.
     */
    @Deprecated public void setBluetoothA2dpOn(boolean on){
    }

    
Checks whether a Bluetooth A2DP audio peripheral is connected or not.

Returns:true if a Bluetooth A2DP peripheral is connected
        false if otherwise
Deprecated:Use getDevices(int) instead to list available audio devices.
/**
     * Checks whether a Bluetooth A2DP audio peripheral is connected or not.
     *
     * @return true if a Bluetooth A2DP peripheral is connected
     *         false if otherwise
     * @deprecated Use {@link AudioManager#getDevices(int)} instead to list available audio devices.
     */
    public boolean isBluetoothA2dpOn() {
        if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_BLUETOOTH_A2DP,"")
                == AudioSystem.DEVICE_STATE_AVAILABLE) {
            return true;
        } else if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES,"")
                == AudioSystem.DEVICE_STATE_AVAILABLE) {
            return true;
        } else if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER,"")
                == AudioSystem.DEVICE_STATE_AVAILABLE) {
            return true;
        }
        return false;
    }

    
Sets audio routing to the wired headset on or off.

Params:
  • on – set true to route audio to/from wired
          headset; false disable wired headset audio
Deprecated:Do not use.
/**
     * Sets audio routing to the wired headset on or off.
     *
     * @param on set <var>true</var> to route audio to/from wired
     *           headset; <var>false</var> disable wired headset audio
     * @deprecated Do not use.
     */
    @Deprecated public void setWiredHeadsetOn(boolean on){
    }

    
Checks whether a wired headset is connected or not.

This is not a valid indication that audio playback is
actually over the wired headset as audio routing depends on other conditions.

Returns:true if a wired headset is connected.
        false if otherwise
Deprecated:Use getDevices(int) instead to list available audio devices.
/**
     * Checks whether a wired headset is connected or not.
     * <p>This is not a valid indication that audio playback is
     * actually over the wired headset as audio routing depends on other conditions.
     *
     * @return true if a wired headset is connected.
     *         false if otherwise
     * @deprecated Use {@link AudioManager#getDevices(int)} instead to list available audio devices.
     */
    public boolean isWiredHeadsetOn() {
        if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_WIRED_HEADSET,"")
                == AudioSystem.DEVICE_STATE_UNAVAILABLE &&
            AudioSystem.getDeviceConnectionState(DEVICE_OUT_WIRED_HEADPHONE,"")
                == AudioSystem.DEVICE_STATE_UNAVAILABLE &&
            AudioSystem.getDeviceConnectionState(DEVICE_OUT_USB_HEADSET, "")
              == AudioSystem.DEVICE_STATE_UNAVAILABLE) {
            return false;
        } else {
            return true;
        }
    }

    
Sets the microphone mute on or off.


This method should only be used by applications that replace the platform-wide
management of audio settings or the main telephony application.

Params:
  • on – set true to mute the microphone;
          false to turn mute off
/**
     * Sets the microphone mute on or off.
     * <p>
     * This method should only be used by applications that replace the platform-wide
     * management of audio settings or the main telephony application.
     *
     * @param on set <var>true</var> to mute the microphone;
     *           <var>false</var> to turn mute off
     */
    public void setMicrophoneMute(boolean on) {
        final IAudioService service = getService();
        try {
            service.setMicrophoneMute(on, getContext().getOpPackageName(),
                    UserHandle.getCallingUserId());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Checks whether the microphone mute is on or off.

Returns:true if microphone is muted, false if it's not
/**
     * Checks whether the microphone mute is on or off.
     *
     * @return true if microphone is muted, false if it's not
     */
    public boolean isMicrophoneMute() {
        return AudioSystem.isMicrophoneMuted();
    }

    
Broadcast Action: microphone muting state changed.
You cannot receive this through components declared in manifests, only by explicitly registering for it with 
Context.registerReceiver(). 
The intent has no extra values, use isMicrophoneMute to check whether the microphone is muted. 
/**
     * Broadcast Action: microphone muting state changed.
     *
     * You <em>cannot</em> receive this through components declared
     * in manifests, only by explicitly registering for it with
     * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)
     * Context.registerReceiver()}.
     *
     * <p>The intent has no extra values, use {@link #isMicrophoneMute} to check whether the
     * microphone is muted.
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_MICROPHONE_MUTE_CHANGED =
            "android.media.action.MICROPHONE_MUTE_CHANGED";

    
Sets the audio mode.

 The audio mode encompasses audio routing AND the behavior of the telephony layer. Therefore this method should only be used by applications that replace the platform-wide management of audio settings or the main telephony application. In particular, the MODE_IN_CALL mode should only be used by the telephony application when it places a phone call, as it will cause signals from the radio layer to feed the platform mixer. 
Params:
/**
     * Sets the audio mode.
     * <p>
     * The audio mode encompasses audio routing AND the behavior of
     * the telephony layer. Therefore this method should only be used by applications that
     * replace the platform-wide management of audio settings or the main telephony application.
     * In particular, the {@link #MODE_IN_CALL} mode should only be used by the telephony
     * application when it places a phone call, as it will cause signals from the radio layer
     * to feed the platform mixer.
     *
     * @param mode  the requested audio mode ({@link #MODE_NORMAL}, {@link #MODE_RINGTONE},
     *              {@link #MODE_IN_CALL} or {@link #MODE_IN_COMMUNICATION}).
     *              Informs the HAL about the current audio state so that
     *              it can route the audio appropriately.
     */
    public void setMode(int mode) {
        final IAudioService service = getService();
        try {
            service.setMode(mode, mICallBack, mApplicationContext.getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns the current audio mode.

Returns: the current audio mode (MODE_NORMAL, MODE_RINGTONE, MODE_IN_CALL or MODE_IN_COMMUNICATION). Returns the current current audio state from the HAL.
/**
     * Returns the current audio mode.
     *
     * @return      the current audio mode ({@link #MODE_NORMAL}, {@link #MODE_RINGTONE},
     *              {@link #MODE_IN_CALL} or {@link #MODE_IN_COMMUNICATION}).
     *              Returns the current current audio state from the HAL.
     */
    public int getMode() {
        final IAudioService service = getService();
        try {
            return service.getMode();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    /* modes for setMode/getMode/setRoute/getRoute */
    /**
     * Audio harware modes.
     */
    
Invalid audio mode.

/**
     * Invalid audio mode.
     */
    public static final int MODE_INVALID            = AudioSystem.MODE_INVALID;
    
Current audio mode. Used to apply audio routing to current mode.

/**
     * Current audio mode. Used to apply audio routing to current mode.
     */
    public static final int MODE_CURRENT            = AudioSystem.MODE_CURRENT;
    
Normal audio mode: not ringing and no call established.

/**
     * Normal audio mode: not ringing and no call established.
     */
    public static final int MODE_NORMAL             = AudioSystem.MODE_NORMAL;
    
Ringing audio mode. An incoming is being signaled.

/**
     * Ringing audio mode. An incoming is being signaled.
     */
    public static final int MODE_RINGTONE           = AudioSystem.MODE_RINGTONE;
    
In call audio mode. A telephony call is established.

/**
     * In call audio mode. A telephony call is established.
     */
    public static final int MODE_IN_CALL            = AudioSystem.MODE_IN_CALL;
    
In communication audio mode. An audio/video chat or VoIP call is established.

/**
     * In communication audio mode. An audio/video chat or VoIP call is established.
     */
    public static final int MODE_IN_COMMUNICATION   = AudioSystem.MODE_IN_COMMUNICATION;

    /* Routing bits for setRouting/getRouting API */
    
Routing audio output to earpiece

Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * Routing audio output to earpiece
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated public static final int ROUTE_EARPIECE          = AudioSystem.ROUTE_EARPIECE;
    
Routing audio output to speaker

Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * Routing audio output to speaker
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated public static final int ROUTE_SPEAKER           = AudioSystem.ROUTE_SPEAKER;
    
Deprecated:use ROUTE_BLUETOOTH_SCO
Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * @deprecated use {@link #ROUTE_BLUETOOTH_SCO}
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated public static final int ROUTE_BLUETOOTH = AudioSystem.ROUTE_BLUETOOTH_SCO;
    
Routing audio output to bluetooth SCO

Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * Routing audio output to bluetooth SCO
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated public static final int ROUTE_BLUETOOTH_SCO     = AudioSystem.ROUTE_BLUETOOTH_SCO;
    
Routing audio output to headset

Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * Routing audio output to headset
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated public static final int ROUTE_HEADSET           = AudioSystem.ROUTE_HEADSET;
    
Routing audio output to bluetooth A2DP

Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * Routing audio output to bluetooth A2DP
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated public static final int ROUTE_BLUETOOTH_A2DP    = AudioSystem.ROUTE_BLUETOOTH_A2DP;
    
Used for mask parameter of setRouting(int, int, int). 
Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * Used for mask parameter of {@link #setRouting(int,int,int)}.
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated public static final int ROUTE_ALL               = AudioSystem.ROUTE_ALL;

    
Sets the audio routing for a specified mode

Params:
  • mode –   audio mode to change route. E.g., MODE_RINGTONE.
  • routes – bit vector of routes requested, created from one or
              more of ROUTE_xxx types. Set bits indicate that route should be on
  • mask –   bit vector of routes to change, created from one or more of
ROUTE_xxx types. Unset bits indicate the route should be left unchanged
Deprecated:  Do not set audio routing directly, use setSpeakerphoneOn(),
setBluetoothScoOn() methods instead.
/**
     * Sets the audio routing for a specified mode
     *
     * @param mode   audio mode to change route. E.g., MODE_RINGTONE.
     * @param routes bit vector of routes requested, created from one or
     *               more of ROUTE_xxx types. Set bits indicate that route should be on
     * @param mask   bit vector of routes to change, created from one or more of
     * ROUTE_xxx types. Unset bits indicate the route should be left unchanged
     *
     * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
     * setBluetoothScoOn() methods instead.
     */
    @Deprecated
    public void setRouting(int mode, int routes, int mask) {
    }

    
Returns the current audio routing bit vector for a specified mode.

Params:
  • mode – audio mode to get route (e.g., MODE_RINGTONE)
Returns:an audio route bit vector that can be compared with ROUTE_xxx
bits
Deprecated:  Do not query audio routing directly, use isSpeakerphoneOn(),
isBluetoothScoOn(), isBluetoothA2dpOn() and isWiredHeadsetOn() methods instead.
/**
     * Returns the current audio routing bit vector for a specified mode.
     *
     * @param mode audio mode to get route (e.g., MODE_RINGTONE)
     * @return an audio route bit vector that can be compared with ROUTE_xxx
     * bits
     * @deprecated   Do not query audio routing directly, use isSpeakerphoneOn(),
     * isBluetoothScoOn(), isBluetoothA2dpOn() and isWiredHeadsetOn() methods instead.
     */
    @Deprecated
    public int getRouting(int mode) {
        return -1;
    }

    
Checks whether any music is active.

Returns:true if any music tracks are active.
/**
     * Checks whether any music is active.
     *
     * @return true if any music tracks are active.
     */
    public boolean isMusicActive() {
        return AudioSystem.isStreamActive(STREAM_MUSIC, 0);
    }

    
@hide
Checks whether any music or media is actively playing on a remote device (e.g. wireless
  display). Note that BT audio sinks are not considered remote devices.
Returns:true if STREAM_MUSIC is active on a remote device
/**
     * @hide
     * Checks whether any music or media is actively playing on a remote device (e.g. wireless
     *   display). Note that BT audio sinks are not considered remote devices.
     * @return true if {@link AudioManager#STREAM_MUSIC} is active on a remote device
     */
    public boolean isMusicActiveRemotely() {
        return AudioSystem.isStreamActiveRemotely(STREAM_MUSIC, 0);
    }

    
@hide
Checks whether the current audio focus is exclusive.
Returns:true if the top of the audio focus stack requested focus with AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE
/**
     * @hide
     * Checks whether the current audio focus is exclusive.
     * @return true if the top of the audio focus stack requested focus
     *     with {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE}
     */
    public boolean isAudioFocusExclusive() {
        final IAudioService service = getService();
        try {
            return service.getCurrentAudioFocus() == AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE;
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Return a new audio session identifier not associated with any player or effect.
An audio session identifier is a system wide unique identifier for a set of audio streams
(one or more mixed together).

The primary use of the audio session ID is to associate audio effects to audio players, such as MediaPlayer or AudioTrack: all audio effects sharing the same audio session ID will be applied to the mixed audio content of the players that share the same audio session. 
This method can for instance be used when creating one of the AudioEffect objects to define the audio session of the effect, or to specify a session for a speech synthesis utterance in Engine. 
Returns:a new unclaimed and unused audio session identifier, or ERROR when the system failed to generate a new session, a condition in which audio playback or recording will subsequently fail as well.
/**
     * Return a new audio session identifier not associated with any player or effect.
     * An audio session identifier is a system wide unique identifier for a set of audio streams
     * (one or more mixed together).
     * <p>The primary use of the audio session ID is to associate audio effects to audio players,
     * such as {@link MediaPlayer} or {@link AudioTrack}: all audio effects sharing the same audio
     * session ID will be applied to the mixed audio content of the players that share the same
     * audio session.
     * <p>This method can for instance be used when creating one of the
     * {@link android.media.audiofx.AudioEffect} objects to define the audio session of the effect,
     * or to specify a session for a speech synthesis utterance
     * in {@link android.speech.tts.TextToSpeech.Engine}.
     * @return a new unclaimed and unused audio session identifier, or {@link #ERROR} when the
     *   system failed to generate a new session, a condition in which audio playback or recording
     *   will subsequently fail as well.
     */
    public int generateAudioSessionId() {
        int session = AudioSystem.newAudioSessionId();
        if (session > 0) {
            return session;
        } else {
            Log.e(TAG, "Failure to generate a new audio session ID");
            return ERROR;
        }
    }

    
A special audio session ID to indicate that the audio session ID isn't known and the framework should generate a new value. This can be used when building a new AudioTrack instance with AudioTrack(AudioAttributes, AudioFormat, int, int, int). 
/**
     * A special audio session ID to indicate that the audio session ID isn't known and the
     * framework should generate a new value. This can be used when building a new
     * {@link AudioTrack} instance with
     * {@link AudioTrack#AudioTrack(AudioAttributes, AudioFormat, int, int, int)}.
     */
    public static final int AUDIO_SESSION_ID_GENERATE = AudioSystem.AUDIO_SESSION_ALLOCATE;


    /*
     * Sets a generic audio configuration parameter. The use of these parameters
     * are platform dependant, see libaudio
     *
     * ** Temporary interface - DO NOT USE
     *
     * TODO: Replace with a more generic key:value get/set mechanism
     *
     * param key   name of parameter to set. Must not be null.
     * param value value of parameter. Must not be null.
     */
    
@hide
Deprecated:Use setParameters(String) instead
/**
     * @hide
     * @deprecated Use {@link #setParameters(String)} instead
     */
    @Deprecated public void setParameter(String key, String value) {
        setParameters(key+"="+value);
    }

    
Sets a variable number of parameter values to audio hardware.

Params:
  • keyValuePairs – list of parameters key value pairs in the form:
   key1=value1;key2=value2;...
/**
     * Sets a variable number of parameter values to audio hardware.
     *
     * @param keyValuePairs list of parameters key value pairs in the form:
     *    key1=value1;key2=value2;...
     *
     */
    public void setParameters(String keyValuePairs) {
        AudioSystem.setParameters(keyValuePairs);
    }

    
Gets a variable number of parameter values from audio hardware.

Params:
  • keys – list of parameters
Returns:list of parameters key value pairs in the form:
   key1=value1;key2=value2;...
/**
     * Gets a variable number of parameter values from audio hardware.
     *
     * @param keys list of parameters
     * @return list of parameters key value pairs in the form:
     *    key1=value1;key2=value2;...
     */
    public String getParameters(String keys) {
        return AudioSystem.getParameters(keys);
    }

    /* Sound effect identifiers */
    
Keyboard and direction pad click sound

See Also:
  • playSoundEffect(int)
/**
     * Keyboard and direction pad click sound
     * @see #playSoundEffect(int)
     */
    public static final int FX_KEY_CLICK = 0;
    
Focus has moved up

See Also:
  • playSoundEffect(int)
/**
     * Focus has moved up
     * @see #playSoundEffect(int)
     */
    public static final int FX_FOCUS_NAVIGATION_UP = 1;
    
Focus has moved down

See Also:
  • playSoundEffect(int)
/**
     * Focus has moved down
     * @see #playSoundEffect(int)
     */
    public static final int FX_FOCUS_NAVIGATION_DOWN = 2;
    
Focus has moved left

See Also:
  • playSoundEffect(int)
/**
     * Focus has moved left
     * @see #playSoundEffect(int)
     */
    public static final int FX_FOCUS_NAVIGATION_LEFT = 3;
    
Focus has moved right

See Also:
  • playSoundEffect(int)
/**
     * Focus has moved right
     * @see #playSoundEffect(int)
     */
    public static final int FX_FOCUS_NAVIGATION_RIGHT = 4;
    
IME standard keypress sound

See Also:
  • playSoundEffect(int)
/**
     * IME standard keypress sound
     * @see #playSoundEffect(int)
     */
    public static final int FX_KEYPRESS_STANDARD = 5;
    
IME spacebar keypress sound

See Also:
  • playSoundEffect(int)
/**
     * IME spacebar keypress sound
     * @see #playSoundEffect(int)
     */
    public static final int FX_KEYPRESS_SPACEBAR = 6;
    
IME delete keypress sound

See Also:
  • playSoundEffect(int)
/**
     * IME delete keypress sound
     * @see #playSoundEffect(int)
     */
    public static final int FX_KEYPRESS_DELETE = 7;
    
IME return_keypress sound

See Also:
  • playSoundEffect(int)
/**
     * IME return_keypress sound
     * @see #playSoundEffect(int)
     */
    public static final int FX_KEYPRESS_RETURN = 8;

    
Invalid keypress sound

See Also:
  • playSoundEffect(int)
/**
     * Invalid keypress sound
     * @see #playSoundEffect(int)
     */
    public static final int FX_KEYPRESS_INVALID = 9;
    
@hideNumber of sound effects
/**
     * @hide Number of sound effects
     */
    public static final int NUM_SOUND_EFFECTS = 10;

    
Plays a sound effect (Key clicks, lid open/close...)

Params:
/**
     * Plays a sound effect (Key clicks, lid open/close...)
     * @param effectType The type of sound effect. One of
     *            {@link #FX_KEY_CLICK},
     *            {@link #FX_FOCUS_NAVIGATION_UP},
     *            {@link #FX_FOCUS_NAVIGATION_DOWN},
     *            {@link #FX_FOCUS_NAVIGATION_LEFT},
     *            {@link #FX_FOCUS_NAVIGATION_RIGHT},
     *            {@link #FX_KEYPRESS_STANDARD},
     *            {@link #FX_KEYPRESS_SPACEBAR},
     *            {@link #FX_KEYPRESS_DELETE},
     *            {@link #FX_KEYPRESS_RETURN},
     *            {@link #FX_KEYPRESS_INVALID},
     * NOTE: This version uses the UI settings to determine
     * whether sounds are heard or not.
     */
    public void  playSoundEffect(int effectType) {
        if (effectType < 0 || effectType >= NUM_SOUND_EFFECTS) {
            return;
        }

        if (!querySoundEffectsEnabled(Process.myUserHandle().getIdentifier())) {
            return;
        }

        final IAudioService service = getService();
        try {
            service.playSoundEffect(effectType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Plays a sound effect (Key clicks, lid open/close...)

Params:
@hide
/**
     * Plays a sound effect (Key clicks, lid open/close...)
     * @param effectType The type of sound effect. One of
     *            {@link #FX_KEY_CLICK},
     *            {@link #FX_FOCUS_NAVIGATION_UP},
     *            {@link #FX_FOCUS_NAVIGATION_DOWN},
     *            {@link #FX_FOCUS_NAVIGATION_LEFT},
     *            {@link #FX_FOCUS_NAVIGATION_RIGHT},
     *            {@link #FX_KEYPRESS_STANDARD},
     *            {@link #FX_KEYPRESS_SPACEBAR},
     *            {@link #FX_KEYPRESS_DELETE},
     *            {@link #FX_KEYPRESS_RETURN},
     *            {@link #FX_KEYPRESS_INVALID},
     * @param userId The current user to pull sound settings from
     * NOTE: This version uses the UI settings to determine
     * whether sounds are heard or not.
     * @hide
     */
    public void  playSoundEffect(int effectType, int userId) {
        if (effectType < 0 || effectType >= NUM_SOUND_EFFECTS) {
            return;
        }

        if (!querySoundEffectsEnabled(userId)) {
            return;
        }

        final IAudioService service = getService();
        try {
            service.playSoundEffect(effectType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Plays a sound effect (Key clicks, lid open/close...)

Params:
/**
     * Plays a sound effect (Key clicks, lid open/close...)
     * @param effectType The type of sound effect. One of
     *            {@link #FX_KEY_CLICK},
     *            {@link #FX_FOCUS_NAVIGATION_UP},
     *            {@link #FX_FOCUS_NAVIGATION_DOWN},
     *            {@link #FX_FOCUS_NAVIGATION_LEFT},
     *            {@link #FX_FOCUS_NAVIGATION_RIGHT},
     *            {@link #FX_KEYPRESS_STANDARD},
     *            {@link #FX_KEYPRESS_SPACEBAR},
     *            {@link #FX_KEYPRESS_DELETE},
     *            {@link #FX_KEYPRESS_RETURN},
     *            {@link #FX_KEYPRESS_INVALID},
     * @param volume Sound effect volume.
     * The volume value is a raw scalar so UI controls should be scaled logarithmically.
     * If a volume of -1 is specified, the AudioManager.STREAM_MUSIC stream volume minus 3dB will be used.
     * NOTE: This version is for applications that have their own
     * settings panel for enabling and controlling volume.
     */
    public void  playSoundEffect(int effectType, float volume) {
        if (effectType < 0 || effectType >= NUM_SOUND_EFFECTS) {
            return;
        }

        final IAudioService service = getService();
        try {
            service.playSoundEffectVolume(effectType, volume);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Settings has an in memory cache, so this is fast.

/**
     * Settings has an in memory cache, so this is fast.
     */
    private boolean querySoundEffectsEnabled(int user) {
        return Settings.System.getIntForUser(getContext().getContentResolver(),
                Settings.System.SOUND_EFFECTS_ENABLED, 0, user) != 0;
    }

    
 Load Sound effects.
 This method must be called when sound effects are enabled.

/**
     *  Load Sound effects.
     *  This method must be called when sound effects are enabled.
     */
    public void loadSoundEffects() {
        final IAudioService service = getService();
        try {
            service.loadSoundEffects();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
 Unload Sound effects.
 This method can be called to free some memory when
 sound effects are disabled.

/**
     *  Unload Sound effects.
     *  This method can be called to free some memory when
     *  sound effects are disabled.
     */
    public void unloadSoundEffects() {
        final IAudioService service = getService();
        try {
            service.unloadSoundEffects();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Used to indicate no audio focus has been gained or lost, or requested.

/**
     * Used to indicate no audio focus has been gained or lost, or requested.
     */
    public static final int AUDIOFOCUS_NONE = 0;

    
Used to indicate a gain of audio focus, or a request of audio focus, of unknown duration.

See Also:
/**
     * Used to indicate a gain of audio focus, or a request of audio focus, of unknown duration.
     * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
     * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
     */
    public static final int AUDIOFOCUS_GAIN = 1;
    
Used to indicate a temporary gain or request of audio focus, anticipated to last a short
amount of time. Examples of temporary changes are the playback of driving directions, or an
event notification.

See Also:
/**
     * Used to indicate a temporary gain or request of audio focus, anticipated to last a short
     * amount of time. Examples of temporary changes are the playback of driving directions, or an
     * event notification.
     * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
     * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
     */
    public static final int AUDIOFOCUS_GAIN_TRANSIENT = 2;
    
Used to indicate a temporary request of audio focus, anticipated to last a short
amount of time, and where it is acceptable for other audio applications to keep playing
after having lowered their output level (also referred to as "ducking").
Examples of temporary changes are the playback of driving directions where playback of music
in the background is acceptable.

See Also:
/**
     * Used to indicate a temporary request of audio focus, anticipated to last a short
     * amount of time, and where it is acceptable for other audio applications to keep playing
     * after having lowered their output level (also referred to as "ducking").
     * Examples of temporary changes are the playback of driving directions where playback of music
     * in the background is acceptable.
     * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
     * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
     */
    public static final int AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK = 3;
    
Used to indicate a temporary request of audio focus, anticipated to last a short
amount of time, during which no other applications, or system components, should play
anything. Examples of exclusive and transient audio focus requests are voice
memo recording and speech recognition, during which the system shouldn't play any
notifications, and media playback should have paused.

See Also:
  • requestAudioFocus(OnAudioFocusChangeListener, int, int)
/**
     * Used to indicate a temporary request of audio focus, anticipated to last a short
     * amount of time, during which no other applications, or system components, should play
     * anything. Examples of exclusive and transient audio focus requests are voice
     * memo recording and speech recognition, during which the system shouldn't play any
     * notifications, and media playback should have paused.
     * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
     */
    public static final int AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE = 4;
    
Used to indicate a loss of audio focus of unknown duration.

See Also:
  • onAudioFocusChange.onAudioFocusChange(int)
/**
     * Used to indicate a loss of audio focus of unknown duration.
     * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
     */
    public static final int AUDIOFOCUS_LOSS = -1 * AUDIOFOCUS_GAIN;
    
Used to indicate a transient loss of audio focus.

See Also:
  • onAudioFocusChange.onAudioFocusChange(int)
/**
     * Used to indicate a transient loss of audio focus.
     * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
     */
    public static final int AUDIOFOCUS_LOSS_TRANSIENT = -1 * AUDIOFOCUS_GAIN_TRANSIENT;
    
Used to indicate a transient loss of audio focus where the loser of the audio focus can
lower its output volume if it wants to continue playing (also referred to as "ducking"), as
the new focus owner doesn't require others to be silent.

See Also:
  • onAudioFocusChange.onAudioFocusChange(int)
/**
     * Used to indicate a transient loss of audio focus where the loser of the audio focus can
     * lower its output volume if it wants to continue playing (also referred to as "ducking"), as
     * the new focus owner doesn't require others to be silent.
     * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
     */
    public static final int AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK =
            -1 * AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK;

    
Interface definition for a callback to be invoked when the audio focus of the system is
updated.

/**
     * Interface definition for a callback to be invoked when the audio focus of the system is
     * updated.
     */
    public interface OnAudioFocusChangeListener {
        
Called on the listener to notify it the audio focus for this listener has been changed.
The focusChange value indicates whether the focus was gained,
whether the focus was lost, and whether that loss is transient, or whether the new focus
holder will hold it for an unknown amount of time.
When losing focus, listeners can use the focus change information to decide what
behavior to adopt when losing focus. A music player could for instance elect to lower
the volume of its music stream (duck) for transient focus losses, and pause otherwise.

Params:
/**
         * Called on the listener to notify it the audio focus for this listener has been changed.
         * The focusChange value indicates whether the focus was gained,
         * whether the focus was lost, and whether that loss is transient, or whether the new focus
         * holder will hold it for an unknown amount of time.
         * When losing focus, listeners can use the focus change information to decide what
         * behavior to adopt when losing focus. A music player could for instance elect to lower
         * the volume of its music stream (duck) for transient focus losses, and pause otherwise.
         * @param focusChange the type of focus change, one of {@link AudioManager#AUDIOFOCUS_GAIN},
         *   {@link AudioManager#AUDIOFOCUS_LOSS}, {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT}
         *   and {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK}.
         */
        public void onAudioFocusChange(int focusChange);
    }

    
Internal class to hold the AudioFocusRequest as well as the Handler for the callback

/**
     * Internal class to hold the AudioFocusRequest as well as the Handler for the callback
     */
    private static class FocusRequestInfo {
        @NonNull  final AudioFocusRequest mRequest;
        @Nullable final Handler mHandler;
        FocusRequestInfo(@NonNull AudioFocusRequest afr, @Nullable Handler handler) {
            mRequest = afr;
            mHandler = handler;
        }
    }

    
Map to convert focus event listener IDs, as used in the AudioService audio focus stack,
to actual listener objects.

/**
     * Map to convert focus event listener IDs, as used in the AudioService audio focus stack,
     * to actual listener objects.
     */
    private final ConcurrentHashMap<String, FocusRequestInfo> mAudioFocusIdListenerMap =
            new ConcurrentHashMap<String, FocusRequestInfo>();

    private FocusRequestInfo findFocusRequestInfo(String id) {
        return mAudioFocusIdListenerMap.get(id);
    }

    
Handler for events (audio focus change, recording config change) coming from the
audio service.

/**
     * Handler for events (audio focus change, recording config change) coming from the
     * audio service.
     */
    private final ServiceEventHandlerDelegate mServiceEventHandlerDelegate =
            new ServiceEventHandlerDelegate(null);

    
Event types

/**
     * Event types
     */
    private final static int MSSG_FOCUS_CHANGE = 0;
    private final static int MSSG_RECORDING_CONFIG_CHANGE = 1;
    private final static int MSSG_PLAYBACK_CONFIG_CHANGE = 2;

    
Helper class to handle the forwarding of audio service events to the appropriate listener

/**
     * Helper class to handle the forwarding of audio service events to the appropriate listener
     */
    private class ServiceEventHandlerDelegate {
        private final Handler mHandler;

        ServiceEventHandlerDelegate(Handler handler) {
            Looper looper;
            if (handler == null) {
                if ((looper = Looper.myLooper()) == null) {
                    looper = Looper.getMainLooper();
                }
            } else {
                looper = handler.getLooper();
            }

            if (looper != null) {
                // implement the event handler delegate to receive events from audio service
                mHandler = new Handler(looper) {
                    @Override
                    public void handleMessage(Message msg) {
                        switch (msg.what) {
                            case MSSG_FOCUS_CHANGE: {
                                final FocusRequestInfo fri = findFocusRequestInfo((String)msg.obj);
                                if (fri != null)  {
                                    final OnAudioFocusChangeListener listener =
                                            fri.mRequest.getOnAudioFocusChangeListener();
                                    if (listener != null) {
                                        Log.d(TAG, "dispatching onAudioFocusChange("
                                                + msg.arg1 + ") to " + msg.obj);
                                        listener.onAudioFocusChange(msg.arg1);
                                    }
                                }
                            } break;
                            case MSSG_RECORDING_CONFIG_CHANGE: {
                                final RecordConfigChangeCallbackData cbData =
                                        (RecordConfigChangeCallbackData) msg.obj;
                                if (cbData.mCb != null) {
                                    cbData.mCb.onRecordingConfigChanged(cbData.mConfigs);
                                }
                            } break;
                            case MSSG_PLAYBACK_CONFIG_CHANGE: {
                                final PlaybackConfigChangeCallbackData cbData =
                                        (PlaybackConfigChangeCallbackData) msg.obj;
                                if (cbData.mCb != null) {
                                    if (DEBUG) {
                                        Log.d(TAG, "dispatching onPlaybackConfigChanged()");
                                    }
                                    cbData.mCb.onPlaybackConfigChanged(cbData.mConfigs);
                                }
                            } break;
                            default:
                                Log.e(TAG, "Unknown event " + msg.what);
                        }
                    }
                };
            } else {
                mHandler = null;
            }
        }

        Handler getHandler() {
            return mHandler;
        }
    }

    private final IAudioFocusDispatcher mAudioFocusDispatcher = new IAudioFocusDispatcher.Stub() {
        @Override
        public void dispatchAudioFocusChange(int focusChange, String id) {
            final FocusRequestInfo fri = findFocusRequestInfo(id);
            if (fri != null)  {
                final OnAudioFocusChangeListener listener =
                        fri.mRequest.getOnAudioFocusChangeListener();
                if (listener != null) {
                    final Handler h = (fri.mHandler == null) ?
                            mServiceEventHandlerDelegate.getHandler() : fri.mHandler;
                    final Message m = h.obtainMessage(
                            MSSG_FOCUS_CHANGE/*what*/, focusChange/*arg1*/, 0/*arg2 ignored*/,
                            id/*obj*/);
                    h.sendMessage(m);
                }
            }
        }

        @Override
        public void dispatchFocusResultFromExtPolicy(int requestResult, String clientId) {
            synchronized (mFocusRequestsLock) {
                // TODO use generation counter as the key instead
                final BlockingFocusResultReceiver focusReceiver =
                        mFocusRequestsAwaitingResult.remove(clientId);
                if (focusReceiver != null) {
                    focusReceiver.notifyResult(requestResult);
                } else {
                    Log.e(TAG, "dispatchFocusResultFromExtPolicy found no result receiver");
                }
            }
        }
    };

    private String getIdForAudioFocusListener(OnAudioFocusChangeListener l) {
        if (l == null) {
            return new String(this.toString());
        } else {
            return new String(this.toString() + l.toString());
        }
    }

    
Params:
  • afr – the full request parameters
@hide
Registers a listener to be called when audio focus changes and keeps track of the associated
focus request (including Handler to use for the listener).
/**
     * @hide
     * Registers a listener to be called when audio focus changes and keeps track of the associated
     * focus request (including Handler to use for the listener).
     * @param afr the full request parameters
     */
    public void registerAudioFocusRequest(@NonNull AudioFocusRequest afr) {
        final Handler h = afr.getOnAudioFocusChangeListenerHandler();
        final FocusRequestInfo fri = new FocusRequestInfo(afr, (h == null) ? null :
            new ServiceEventHandlerDelegate(h).getHandler());
        final String key = getIdForAudioFocusListener(afr.getOnAudioFocusChangeListener());
        mAudioFocusIdListenerMap.put(key, fri);
    }

    
Params:
  • l – the listener to unregister.
@hide
Causes the specified listener to not be called anymore when focus is gained or lost.
/**
     * @hide
     * Causes the specified listener to not be called anymore when focus is gained or lost.
     * @param l the listener to unregister.
     */
    public void unregisterAudioFocusRequest(OnAudioFocusChangeListener l) {
        // remove locally
        mAudioFocusIdListenerMap.remove(getIdForAudioFocusListener(l));
    }


    
A failed focus change request.

/**
     * A failed focus change request.
     */
    public static final int AUDIOFOCUS_REQUEST_FAILED = 0;
    
A successful focus change request.

/**
     * A successful focus change request.
     */
    public static final int AUDIOFOCUS_REQUEST_GRANTED = 1;
     
A focus change request whose granting is delayed: the request was successful, but the requester will only be granted audio focus once the condition that prevented immediate granting has ended. See requestAudioFocus(AudioFocusRequest) and Builder.setAcceptsDelayedFocusGain(boolean) 
/**
      * A focus change request whose granting is delayed: the request was successful, but the
      * requester will only be granted audio focus once the condition that prevented immediate
      * granting has ended.
      * See {@link #requestAudioFocus(AudioFocusRequest)} and
      * {@link AudioFocusRequest.Builder#setAcceptsDelayedFocusGain(boolean)}
      */
    public static final int AUDIOFOCUS_REQUEST_DELAYED = 2;

    
@hide
/** @hide */
    @IntDef(flag = false, prefix = "AUDIOFOCUS_REQUEST", value = {
            AUDIOFOCUS_REQUEST_FAILED,
            AUDIOFOCUS_REQUEST_GRANTED,
            AUDIOFOCUS_REQUEST_DELAYED }
    )
    @Retention(RetentionPolicy.SOURCE)
    public @interface FocusRequestResult {}

    
@hide
code returned when a synchronous focus request on the client-side is to be blocked
until the external audio focus policy decides on the response for the client
/**
     * @hide
     * code returned when a synchronous focus request on the client-side is to be blocked
     * until the external audio focus policy decides on the response for the client
     */
    public static final int AUDIOFOCUS_REQUEST_WAITING_FOR_EXT_POLICY = 100;

    
Timeout duration in ms when waiting on an external focus policy for the result for a
focus request

/**
     * Timeout duration in ms when waiting on an external focus policy for the result for a
     * focus request
     */
    private static final int EXT_FOCUS_POLICY_TIMEOUT_MS = 200;

    private static final String FOCUS_CLIENT_ID_STRING = "android_audio_focus_client_id";

    private final Object mFocusRequestsLock = new Object();
    
Map of all receivers of focus request results, one per unresolved focus request.
Receivers are added before sending the request to the external focus policy,
and are removed either after receiving the result, or after the timeout.
This variable is lazily initialized.

/**
     * Map of all receivers of focus request results, one per unresolved focus request.
     * Receivers are added before sending the request to the external focus policy,
     * and are removed either after receiving the result, or after the timeout.
     * This variable is lazily initialized.
     */
    @GuardedBy("mFocusRequestsLock")
    private HashMap<String, BlockingFocusResultReceiver> mFocusRequestsAwaitingResult;


    
 Request audio focus. Send a request to obtain the audio focus @param l the listener to be notified of audio focus changes @param streamType the main audio stream type affected by the focus request @param durationHint use AUDIOFOCUS_GAIN_TRANSIENT to indicate this focus request is temporary, and focus will be abandonned shortly. Examples of transient requests are for the playback of driving directions, or notifications sounds. Use AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK to indicate also that it's ok for the previous focus owner to keep playing if it ducks its audio output. Alternatively use AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE for a temporary request that benefits from the system not playing disruptive sounds like notifications, for usecases such as voice memo recording, or speech recognition. Use AUDIOFOCUS_GAIN for a focus request of unknown duration such as the playback of a song or a video. @return AUDIOFOCUS_REQUEST_FAILED or AUDIOFOCUS_REQUEST_GRANTED @deprecated use requestAudioFocus(AudioFocusRequest) 
/**
     *  Request audio focus.
     *  Send a request to obtain the audio focus
     *  @param l the listener to be notified of audio focus changes
     *  @param streamType the main audio stream type affected by the focus request
     *  @param durationHint use {@link #AUDIOFOCUS_GAIN_TRANSIENT} to indicate this focus request
     *      is temporary, and focus will be abandonned shortly. Examples of transient requests are
     *      for the playback of driving directions, or notifications sounds.
     *      Use {@link #AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK} to indicate also that it's ok for
     *      the previous focus owner to keep playing if it ducks its audio output.
     *      Alternatively use {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE} for a temporary request
     *      that benefits from the system not playing disruptive sounds like notifications, for
     *      usecases such as voice memo recording, or speech recognition.
     *      Use {@link #AUDIOFOCUS_GAIN} for a focus request of unknown duration such
     *      as the playback of a song or a video.
     *  @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
     *  @deprecated use {@link #requestAudioFocus(AudioFocusRequest)}
     */
    public int requestAudioFocus(OnAudioFocusChangeListener l, int streamType, int durationHint) {
        PlayerBase.deprecateStreamTypeForPlayback(streamType,
                "AudioManager", "requestAudioFocus()");
        int status = AUDIOFOCUS_REQUEST_FAILED;

        try {
            // status is guaranteed to be either AUDIOFOCUS_REQUEST_FAILED or
            // AUDIOFOCUS_REQUEST_GRANTED as focus is requested without the
            // AUDIOFOCUS_FLAG_DELAY_OK flag
            status = requestAudioFocus(l,
                    new AudioAttributes.Builder()
                            .setInternalLegacyStreamType(streamType).build(),
                    durationHint,
                    0 /* flags, legacy behavior */);
        } catch (IllegalArgumentException e) {
            Log.e(TAG, "Audio focus request denied due to ", e);
        }

        return status;
    }

    // when adding new flags, add them to the relevant AUDIOFOCUS_FLAGS_APPS or SYSTEM masks
    
@hide Use this flag when requesting audio focus to indicate it is ok for the requester to not be granted audio focus immediately (as indicated by AUDIOFOCUS_REQUEST_DELAYED) when the system is in a state where focus cannot change, but be granted focus later when this condition ends.
/**
     * @hide
     * Use this flag when requesting audio focus to indicate it is ok for the requester to not be
     * granted audio focus immediately (as indicated by {@link #AUDIOFOCUS_REQUEST_DELAYED}) when
     * the system is in a state where focus cannot change, but be granted focus later when
     * this condition ends.
     */
    @SystemApi
    public static final int AUDIOFOCUS_FLAG_DELAY_OK = 0x1 << 0;
    
@hide Use this flag when requesting audio focus to indicate that the requester will pause its media playback (if applicable) when losing audio focus with AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK, rather than ducking. 
On some platforms, the ducking may be handled without the application being aware of it
(i.e. it will not transiently lose focus). For applications that for instance play spoken
content, such as audio book or podcast players, ducking may never be acceptable, and will
thus always pause. This flag enables them to be declared as such whenever they request focus.
/**
     * @hide
     * Use this flag when requesting audio focus to indicate that the requester
     * will pause its media playback (if applicable) when losing audio focus with
     * {@link #AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK}, rather than ducking.
     * <br>On some platforms, the ducking may be handled without the application being aware of it
     * (i.e. it will not transiently lose focus). For applications that for instance play spoken
     * content, such as audio book or podcast players, ducking may never be acceptable, and will
     * thus always pause. This flag enables them to be declared as such whenever they request focus.
     */
    @SystemApi
    public static final int AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS = 0x1 << 1;
    
@hide
Use this flag to lock audio focus so granting is temporarily disabled.

This flag can only be used by owners of a registered AudioPolicy in requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int, AudioPolicy)
/**
     * @hide
     * Use this flag to lock audio focus so granting is temporarily disabled.
     * <br>This flag can only be used by owners of a registered
     * {@link android.media.audiopolicy.AudioPolicy} in
     * {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int, AudioPolicy)}
     */
    @SystemApi
    public static final int AUDIOFOCUS_FLAG_LOCK     = 0x1 << 2;
    
@hide
/** @hide */
    public static final int AUDIOFOCUS_FLAGS_APPS = AUDIOFOCUS_FLAG_DELAY_OK
            | AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS;
    
@hide
/** @hide */
    public static final int AUDIOFOCUS_FLAGS_SYSTEM = AUDIOFOCUS_FLAG_DELAY_OK
            | AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS | AUDIOFOCUS_FLAG_LOCK;

    
Request audio focus. See the AudioFocusRequest for information about the options available to configure your request, and notification of focus gain and loss. 
Params:
  • focusRequest – a AudioFocusRequest instance used to configure how focus is requested.
Throws:
Returns:AUDIOFOCUS_REQUEST_FAILED, AUDIOFOCUS_REQUEST_GRANTED or AUDIOFOCUS_REQUEST_DELAYED. 
Note that the return value is never AUDIOFOCUS_REQUEST_DELAYED when focus is requested without building the AudioFocusRequest with Builder.setAcceptsDelayedFocusGain(boolean) set to true.
/**
     * Request audio focus.
     * See the {@link AudioFocusRequest} for information about the options available to configure
     * your request, and notification of focus gain and loss.
     * @param focusRequest a {@link AudioFocusRequest} instance used to configure how focus is
     *   requested.
     * @return {@link #AUDIOFOCUS_REQUEST_FAILED}, {@link #AUDIOFOCUS_REQUEST_GRANTED}
     *     or {@link #AUDIOFOCUS_REQUEST_DELAYED}.
     *     <br>Note that the return value is never {@link #AUDIOFOCUS_REQUEST_DELAYED} when focus
     *     is requested without building the {@link AudioFocusRequest} with
     *     {@link AudioFocusRequest.Builder#setAcceptsDelayedFocusGain(boolean)} set to
     *     {@code true}.
     * @throws NullPointerException if passed a null argument
     */
    public int requestAudioFocus(@NonNull AudioFocusRequest focusRequest) {
        return requestAudioFocus(focusRequest, null /* no AudioPolicy*/);
    }

    
 Abandon audio focus. Causes the previous focus owner, if any, to receive focus. @param focusRequest the AudioFocusRequest that was used when requesting focus with requestAudioFocus(AudioFocusRequest). @return AUDIOFOCUS_REQUEST_FAILED or AUDIOFOCUS_REQUEST_GRANTED @throws IllegalArgumentException if passed a null argument 
/**
     *  Abandon audio focus. Causes the previous focus owner, if any, to receive focus.
     *  @param focusRequest the {@link AudioFocusRequest} that was used when requesting focus
     *      with {@link #requestAudioFocus(AudioFocusRequest)}.
     *  @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
     *  @throws IllegalArgumentException if passed a null argument
     */
    public int abandonAudioFocusRequest(@NonNull AudioFocusRequest focusRequest) {
        if (focusRequest == null) {
            throw new IllegalArgumentException("Illegal null AudioFocusRequest");
        }
        return abandonAudioFocus(focusRequest.getOnAudioFocusChangeListener(),
                focusRequest.getAudioAttributes());
    }

    
Params:
  • l – the listener to be notified of audio focus changes. It is not allowed to be null when the request is flagged with AUDIOFOCUS_FLAG_DELAY_OK.
  • requestAttributes – non null AudioAttributes describing the main reason for requesting audio focus.
  • durationHint – use AUDIOFOCUS_GAIN_TRANSIENT to indicate this focus request is temporary, and focus will be abandonned shortly. Examples of transient requests are for the playback of driving directions, or notifications sounds. Use AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK to indicate also that it's ok for the previous focus owner to keep playing if it ducks its audio output. Alternatively use AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE for a temporary request that benefits from the system not playing disruptive sounds like notifications, for usecases such as voice memo recording, or speech recognition. Use AUDIOFOCUS_GAIN for a focus request of unknown duration such as the playback of a song or a video.
  • flags – 0 or a combination of {link #AUDIOFOCUS_FLAG_DELAY_OK}, AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS and AUDIOFOCUS_FLAG_LOCK. 
    Use 0 when not using any flags for the request, which behaves like requestAudioFocus(OnAudioFocusChangeListener, int, int), where either audio focus is granted immediately, or the grant request fails because the system is in a state where focus cannot change (e.g. a phone call).
Throws:
@hide Request audio focus. Send a request to obtain the audio focus. This method differs from requestAudioFocus(OnAudioFocusChangeListener, int, int) in that it can express that the requester accepts delayed grants of audio focus.
Returns:AUDIOFOCUS_REQUEST_FAILED, AUDIOFOCUS_REQUEST_GRANTED or AUDIOFOCUS_REQUEST_DELAYED. The return value is never AUDIOFOCUS_REQUEST_DELAYED when focus is requested without the AUDIOFOCUS_FLAG_DELAY_OK flag.
/**
     * @hide
     * Request audio focus.
     * Send a request to obtain the audio focus. This method differs from
     * {@link #requestAudioFocus(OnAudioFocusChangeListener, int, int)} in that it can express
     * that the requester accepts delayed grants of audio focus.
     * @param l the listener to be notified of audio focus changes. It is not allowed to be null
     *     when the request is flagged with {@link #AUDIOFOCUS_FLAG_DELAY_OK}.
     * @param requestAttributes non null {@link AudioAttributes} describing the main reason for
     *     requesting audio focus.
     * @param durationHint use {@link #AUDIOFOCUS_GAIN_TRANSIENT} to indicate this focus request
     *      is temporary, and focus will be abandonned shortly. Examples of transient requests are
     *      for the playback of driving directions, or notifications sounds.
     *      Use {@link #AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK} to indicate also that it's ok for
     *      the previous focus owner to keep playing if it ducks its audio output.
     *      Alternatively use {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE} for a temporary request
     *      that benefits from the system not playing disruptive sounds like notifications, for
     *      usecases such as voice memo recording, or speech recognition.
     *      Use {@link #AUDIOFOCUS_GAIN} for a focus request of unknown duration such
     *      as the playback of a song or a video.
     * @param flags 0 or a combination of {link #AUDIOFOCUS_FLAG_DELAY_OK},
     *     {@link #AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS} and {@link #AUDIOFOCUS_FLAG_LOCK}.
     *     <br>Use 0 when not using any flags for the request, which behaves like
     *     {@link #requestAudioFocus(OnAudioFocusChangeListener, int, int)}, where either audio
     *     focus is granted immediately, or the grant request fails because the system is in a
     *     state where focus cannot change (e.g. a phone call).
     * @return {@link #AUDIOFOCUS_REQUEST_FAILED}, {@link #AUDIOFOCUS_REQUEST_GRANTED}
     *     or {@link #AUDIOFOCUS_REQUEST_DELAYED}.
     *     The return value is never {@link #AUDIOFOCUS_REQUEST_DELAYED} when focus is requested
     *     without the {@link #AUDIOFOCUS_FLAG_DELAY_OK} flag.
     * @throws IllegalArgumentException
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.MODIFY_PHONE_STATE)
    public int requestAudioFocus(OnAudioFocusChangeListener l,
            @NonNull AudioAttributes requestAttributes,
            int durationHint,
            int flags) throws IllegalArgumentException {
        if (flags != (flags & AUDIOFOCUS_FLAGS_APPS)) {
            throw new IllegalArgumentException("Invalid flags 0x"
                    + Integer.toHexString(flags).toUpperCase());
        }
        return requestAudioFocus(l, requestAttributes, durationHint,
                flags & AUDIOFOCUS_FLAGS_APPS,
                null /* no AudioPolicy*/);
    }

    
Params:
Throws:
@hide Request or lock audio focus. This method is to be used by system components that have registered an AudioPolicy to request audio focus, but also to "lock" it so focus granting is temporarily disabled.
Returns:see the description of the same return value in requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int)
Deprecated:use requestAudioFocus(AudioFocusRequest, AudioPolicy)
/**
     * @hide
     * Request or lock audio focus.
     * This method is to be used by system components that have registered an
     * {@link android.media.audiopolicy.AudioPolicy} to request audio focus, but also to "lock" it
     * so focus granting is temporarily disabled.
     * @param l see the description of the same parameter in
     *     {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int)}
     * @param requestAttributes non null {@link AudioAttributes} describing the main reason for
     *     requesting audio focus.
     * @param durationHint see the description of the same parameter in
     *     {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int)}
     * @param flags 0 or a combination of {link #AUDIOFOCUS_FLAG_DELAY_OK},
     *     {@link #AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS}, and {@link #AUDIOFOCUS_FLAG_LOCK}.
     *     <br>Use 0 when not using any flags for the request, which behaves like
     *     {@link #requestAudioFocus(OnAudioFocusChangeListener, int, int)}, where either audio
     *     focus is granted immediately, or the grant request fails because the system is in a
     *     state where focus cannot change (e.g. a phone call).
     * @param ap a registered {@link android.media.audiopolicy.AudioPolicy} instance when locking
     *     focus, or null.
     * @return see the description of the same return value in
     *     {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int)}
     * @throws IllegalArgumentException
     * @deprecated use {@link #requestAudioFocus(AudioFocusRequest, AudioPolicy)}
     */
    @SystemApi
    @RequiresPermission(anyOf= {
            android.Manifest.permission.MODIFY_PHONE_STATE,
            android.Manifest.permission.MODIFY_AUDIO_ROUTING
    })
    public int requestAudioFocus(OnAudioFocusChangeListener l,
            @NonNull AudioAttributes requestAttributes,
            int durationHint,
            int flags,
            AudioPolicy ap) throws IllegalArgumentException {
        // parameter checking
        if (requestAttributes == null) {
            throw new IllegalArgumentException("Illegal null AudioAttributes argument");
        }
        if (!AudioFocusRequest.isValidFocusGain(durationHint)) {
            throw new IllegalArgumentException("Invalid duration hint");
        }
        if (flags != (flags & AUDIOFOCUS_FLAGS_SYSTEM)) {
            throw new IllegalArgumentException("Illegal flags 0x"
                + Integer.toHexString(flags).toUpperCase());
        }
        if (((flags & AUDIOFOCUS_FLAG_DELAY_OK) == AUDIOFOCUS_FLAG_DELAY_OK) && (l == null)) {
            throw new IllegalArgumentException(
                    "Illegal null focus listener when flagged as accepting delayed focus grant");
        }
        if (((flags & AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS)
                == AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS) && (l == null)) {
            throw new IllegalArgumentException(
                    "Illegal null focus listener when flagged as pausing instead of ducking");
        }
        if (((flags & AUDIOFOCUS_FLAG_LOCK) == AUDIOFOCUS_FLAG_LOCK) && (ap == null)) {
            throw new IllegalArgumentException(
                    "Illegal null audio policy when locking audio focus");
        }

        final AudioFocusRequest afr = new AudioFocusRequest.Builder(durationHint)
                .setOnAudioFocusChangeListenerInt(l, null /* no Handler for this legacy API */)
                .setAudioAttributes(requestAttributes)
                .setAcceptsDelayedFocusGain((flags & AUDIOFOCUS_FLAG_DELAY_OK)
                        == AUDIOFOCUS_FLAG_DELAY_OK)
                .setWillPauseWhenDucked((flags & AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS)
                        == AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS)
                .setLocksFocus((flags & AUDIOFOCUS_FLAG_LOCK) == AUDIOFOCUS_FLAG_LOCK)
                .build();
        return requestAudioFocus(afr, ap);
    }

    
Params:
Throws:
@hide Request or lock audio focus. This method is to be used by system components that have registered an AudioPolicy to request audio focus, but also to "lock" it so focus granting is temporarily disabled.
Returns:AUDIOFOCUS_REQUEST_FAILED, AUDIOFOCUS_REQUEST_GRANTED or AUDIOFOCUS_REQUEST_DELAYED.
/**
     * @hide
     * Request or lock audio focus.
     * This method is to be used by system components that have registered an
     * {@link android.media.audiopolicy.AudioPolicy} to request audio focus, but also to "lock" it
     * so focus granting is temporarily disabled.
     * @param afr see the description of the same parameter in
     *     {@link #requestAudioFocus(AudioFocusRequest)}
     * @param ap a registered {@link android.media.audiopolicy.AudioPolicy} instance when locking
     *     focus, or null.
     * @return {@link #AUDIOFOCUS_REQUEST_FAILED}, {@link #AUDIOFOCUS_REQUEST_GRANTED}
     *     or {@link #AUDIOFOCUS_REQUEST_DELAYED}.
     * @throws NullPointerException if the AudioFocusRequest is null
     * @throws IllegalArgumentException when trying to lock focus without an AudioPolicy
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
    public int requestAudioFocus(@NonNull AudioFocusRequest afr, @Nullable AudioPolicy ap) {
        if (afr == null) {
            throw new NullPointerException("Illegal null AudioFocusRequest");
        }
        // this can only be checked now, not during the creation of the AudioFocusRequest instance
        if (afr.locksFocus() && ap == null) {
            throw new IllegalArgumentException(
                    "Illegal null audio policy when locking audio focus");
        }
        registerAudioFocusRequest(afr);
        final IAudioService service = getService();
        final int status;
        int sdk;
        try {
            sdk = getContext().getApplicationInfo().targetSdkVersion;
        } catch (NullPointerException e) {
            // some tests don't have a Context
            sdk = Build.VERSION.SDK_INT;
        }

        final String clientId = getIdForAudioFocusListener(afr.getOnAudioFocusChangeListener());
        final BlockingFocusResultReceiver focusReceiver;
        synchronized (mFocusRequestsLock) {
            try {
                // TODO status contains result and generation counter for ext policy
                status = service.requestAudioFocus(afr.getAudioAttributes(),
                        afr.getFocusGain(), mICallBack,
                        mAudioFocusDispatcher,
                        clientId,
                        getContext().getOpPackageName() /* package name */, afr.getFlags(),
                        ap != null ? ap.cb() : null,
                        sdk);
            } catch (RemoteException e) {
                throw e.rethrowFromSystemServer();
            }
            if (status != AudioManager.AUDIOFOCUS_REQUEST_WAITING_FOR_EXT_POLICY) {
                // default path with no external focus policy
                return status;
            }
            if (mFocusRequestsAwaitingResult == null) {
                mFocusRequestsAwaitingResult =
                        new HashMap<String, BlockingFocusResultReceiver>(1);
            }
            focusReceiver = new BlockingFocusResultReceiver(clientId);
            mFocusRequestsAwaitingResult.put(clientId, focusReceiver);
        }
        focusReceiver.waitForResult(EXT_FOCUS_POLICY_TIMEOUT_MS);
        if (DEBUG && !focusReceiver.receivedResult()) {
            Log.e(TAG, "requestAudio response from ext policy timed out, denying request");
        }
        synchronized (mFocusRequestsLock) {
            mFocusRequestsAwaitingResult.remove(clientId);
        }
        return focusReceiver.requestResult();
    }

    // helper class that abstracts out the handling of spurious wakeups in Object.wait()
    private static final class SafeWaitObject {
        private boolean mQuit = false;

        public void safeNotify() {
            synchronized (this) {
                mQuit = true;
                this.notify();
            }
        }

        public void safeWait(long millis) throws InterruptedException {
            final long timeOutTime = java.lang.System.currentTimeMillis() + millis;
            synchronized (this) {
                while (!mQuit) {
                    final long timeToWait = timeOutTime - java.lang.System.currentTimeMillis();
                    if (timeToWait < 0) { break; }
                    this.wait(timeToWait);
                }
            }
        }
    }

    private static final class BlockingFocusResultReceiver {
        private final SafeWaitObject mLock = new SafeWaitObject();
        @GuardedBy("mLock")
        private boolean mResultReceived = false;
        // request denied by default (e.g. timeout)
        private int mFocusRequestResult = AudioManager.AUDIOFOCUS_REQUEST_FAILED;
        private final String mFocusClientId;

        BlockingFocusResultReceiver(String clientId) {
            mFocusClientId = clientId;
        }

        boolean receivedResult() { return mResultReceived; }
        int requestResult() { return mFocusRequestResult; }

        void notifyResult(int requestResult) {
            synchronized (mLock) {
                mResultReceived = true;
                mFocusRequestResult = requestResult;
                mLock.safeNotify();
            }
        }

        public void waitForResult(long timeOutMs) {
            synchronized (mLock) {
                if (mResultReceived) {
                    // the result was received before waiting
                    return;
                }
                try {
                    mLock.safeWait(timeOutMs);
                } catch (InterruptedException e) { }
            }
        }
    }

    
Params:
  • streamType – use STREAM_RING for focus requests when ringing, VOICE_CALL for
   the establishment of the call
  • durationHint – the type of focus request. AUDIOFOCUS_GAIN_TRANSIENT is recommended so
   media applications resume after a call
@hide
Used internally by telephony package to request audio focus. Will cause the focus request
to be associated with the "voice communication" identifier only used in AudioService
to identify this use case.
/**
     * @hide
     * Used internally by telephony package to request audio focus. Will cause the focus request
     * to be associated with the "voice communication" identifier only used in AudioService
     * to identify this use case.
     * @param streamType use STREAM_RING for focus requests when ringing, VOICE_CALL for
     *    the establishment of the call
     * @param durationHint the type of focus request. AUDIOFOCUS_GAIN_TRANSIENT is recommended so
     *    media applications resume after a call
     */
    public void requestAudioFocusForCall(int streamType, int durationHint) {
        final IAudioService service = getService();
        try {
            service.requestAudioFocus(new AudioAttributes.Builder()
                        .setInternalLegacyStreamType(streamType).build(),
                    durationHint, mICallBack, null,
                    AudioSystem.IN_VOICE_COMM_FOCUS_ID,
                    getContext().getOpPackageName(),
                    AUDIOFOCUS_FLAG_LOCK,
                    null /* policy token */, 0 /* sdk n/a here*/);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Params:
  • focusGain – 
  • attr – 
@hide
Return the volume ramping time for a sound to be played after the given focus request,
  and to play a sound of the given attributes
Returns:
/**
     * @hide
     * Return the volume ramping time for a sound to be played after the given focus request,
     *   and to play a sound of the given attributes
     * @param focusGain
     * @param attr
     * @return
     */
    public int getFocusRampTimeMs(int focusGain, AudioAttributes attr) {
        final IAudioService service = getService();
        try {
            return service.getFocusRampTimeMs(focusGain, attr);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Params:
  • afi – the information about the focus requester
  • requestResult – the result to the focus request to be passed to the requester
  • ap – a valid registered AudioPolicy configured as a focus policy.
@hide Set the result to the audio focus request received through AudioPolicyFocusListener.onAudioFocusRequest(AudioFocusInfo, int).
/**
     * @hide
     * Set the result to the audio focus request received through
     * {@link AudioPolicyFocusListener#onAudioFocusRequest(AudioFocusInfo, int)}.
     * @param afi the information about the focus requester
     * @param requestResult the result to the focus request to be passed to the requester
     * @param ap a valid registered {@link AudioPolicy} configured as a focus policy.
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
    public void setFocusRequestResult(@NonNull AudioFocusInfo afi,
            @FocusRequestResult int requestResult, @NonNull AudioPolicy ap) {
        if (afi == null) {
            throw new IllegalArgumentException("Illegal null AudioFocusInfo");
        }
        if (ap == null) {
            throw new IllegalArgumentException("Illegal null AudioPolicy");
        }
        final IAudioService service = getService();
        try {
            service.setFocusRequestResultFromExtPolicy(afi, requestResult, ap.cb());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Params:
Throws:
@hide Notifies an application with a focus listener of gain or loss of audio focus. This method can only be used by owners of an AudioPolicy configured with Builder.setIsAudioFocusPolicy(boolean) set to true.
Returns:AUDIOFOCUS_REQUEST_GRANTED if the dispatch was successfully sent, or AUDIOFOCUS_REQUEST_FAILED if the focus client didn't have a listener, or if there was an error sending the request.
/**
     * @hide
     * Notifies an application with a focus listener of gain or loss of audio focus.
     * This method can only be used by owners of an {@link AudioPolicy} configured with
     * {@link AudioPolicy.Builder#setIsAudioFocusPolicy(boolean)} set to true.
     * @param afi the recipient of the focus change, that has previously requested audio focus, and
     *     that was received by the {@code AudioPolicy} through
     *     {@link AudioPolicy.AudioPolicyFocusListener#onAudioFocusRequest(AudioFocusInfo, int)}.
     * @param focusChange one of focus gain types ({@link #AUDIOFOCUS_GAIN},
     *     {@link #AUDIOFOCUS_GAIN_TRANSIENT}, {@link #AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK} or
     *     {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE})
     *     or one of the focus loss types ({@link AudioManager#AUDIOFOCUS_LOSS},
     *     {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT},
     *     or {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK}).
     *     <br>For the focus gain, the change type should be the same as the app requested.
     * @param ap a valid registered {@link AudioPolicy} configured as a focus policy.
     * @return {@link #AUDIOFOCUS_REQUEST_GRANTED} if the dispatch was successfully sent, or
     *     {@link #AUDIOFOCUS_REQUEST_FAILED} if the focus client didn't have a listener, or
     *     if there was an error sending the request.
     * @throws NullPointerException if the {@link AudioFocusInfo} or {@link AudioPolicy} are null.
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
    public int dispatchAudioFocusChange(@NonNull AudioFocusInfo afi, int focusChange,
            @NonNull AudioPolicy ap) {
        if (afi == null) {
            throw new NullPointerException("Illegal null AudioFocusInfo");
        }
        if (ap == null) {
            throw new NullPointerException("Illegal null AudioPolicy");
        }
        final IAudioService service = getService();
        try {
            return service.dispatchFocusChange(afi, focusChange, ap.cb());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
@hide Used internally by telephony package to abandon audio focus, typically after a call or when ringing ends and the call is rejected or not answered. Should match one or more calls to requestAudioFocusForCall(int, int).
/**
     * @hide
     * Used internally by telephony package to abandon audio focus, typically after a call or
     * when ringing ends and the call is rejected or not answered.
     * Should match one or more calls to {@link #requestAudioFocusForCall(int, int)}.
     */
    public void abandonAudioFocusForCall() {
        final IAudioService service = getService();
        try {
            service.abandonAudioFocus(null, AudioSystem.IN_VOICE_COMM_FOCUS_ID,
                    null /*AudioAttributes, legacy behavior*/, getContext().getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
 Abandon audio focus. Causes the previous focus owner, if any, to receive focus. @param l the listener with which focus was requested. @return AUDIOFOCUS_REQUEST_FAILED or AUDIOFOCUS_REQUEST_GRANTED @deprecated use abandonAudioFocusRequest(AudioFocusRequest) 
/**
     *  Abandon audio focus. Causes the previous focus owner, if any, to receive focus.
     *  @param l the listener with which focus was requested.
     *  @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
     *  @deprecated use {@link #abandonAudioFocusRequest(AudioFocusRequest)}
     */
    public int abandonAudioFocus(OnAudioFocusChangeListener l) {
        return abandonAudioFocus(l, null /*AudioAttributes, legacy behavior*/);
    }

    
Params:
@hide
Abandon audio focus. Causes the previous focus owner, if any, to receive focus.
 @param l the listener with which focus was requested.
Returns:AUDIOFOCUS_REQUEST_FAILED or AUDIOFOCUS_REQUEST_GRANTED
Deprecated:use abandonAudioFocusRequest(AudioFocusRequest)
/**
     * @hide
     * Abandon audio focus. Causes the previous focus owner, if any, to receive focus.
     *  @param l the listener with which focus was requested.
     * @param aa the {@link AudioAttributes} with which audio focus was requested
     * @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
     * @deprecated use {@link #abandonAudioFocusRequest(AudioFocusRequest)}
     */
    @SystemApi
    @SuppressLint("Doclava125") // no permission enforcement, but only "undoes" what would have been
                                // done by a matching requestAudioFocus
    public int abandonAudioFocus(OnAudioFocusChangeListener l, AudioAttributes aa) {
        int status = AUDIOFOCUS_REQUEST_FAILED;
        unregisterAudioFocusRequest(l);
        final IAudioService service = getService();
        try {
            status = service.abandonAudioFocus(mAudioFocusDispatcher,
                    getIdForAudioFocusListener(l), aa, getContext().getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
        return status;
    }

    //====================================================================
    // Remote Control
    
Register a component to be the sole receiver of MEDIA_BUTTON intents.

Params:
  • eventReceiver – identifier of a BroadcastReceiver that will receive the media button intent. This broadcast receiver must be declared in the application manifest. The package of the component must match that of the context you're registering from.
Deprecated:Use MediaSession.setMediaButtonReceiver(PendingIntent) instead.
/**
     * Register a component to be the sole receiver of MEDIA_BUTTON intents.
     * @param eventReceiver identifier of a {@link android.content.BroadcastReceiver}
     *      that will receive the media button intent. This broadcast receiver must be declared
     *      in the application manifest. The package of the component must match that of
     *      the context you're registering from.
     * @deprecated Use {@link MediaSession#setMediaButtonReceiver(PendingIntent)} instead.
     */
    @Deprecated
    public void registerMediaButtonEventReceiver(ComponentName eventReceiver) {
        if (eventReceiver == null) {
            return;
        }
        if (!eventReceiver.getPackageName().equals(getContext().getPackageName())) {
            Log.e(TAG, "registerMediaButtonEventReceiver() error: " +
                    "receiver and context package names don't match");
            return;
        }
        // construct a PendingIntent for the media button and register it
        Intent mediaButtonIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
        //     the associated intent will be handled by the component being registered
        mediaButtonIntent.setComponent(eventReceiver);
        PendingIntent pi = PendingIntent.getBroadcast(getContext(),
                0/*requestCode, ignored*/, mediaButtonIntent, 0/*flags*/);
        registerMediaButtonIntent(pi, eventReceiver);
    }

    
Register a component to be the sole receiver of MEDIA_BUTTON intents. This is like registerMediaButtonEventReceiver(ComponentName), but allows the buttons to go to any PendingIntent. Note that you should only use this form if you know you will continue running for the full time until unregistering the PendingIntent. 
Params:
  • eventReceiver – target that will receive media button intents. The PendingIntent will be sent an Intent.ACTION_MEDIA_BUTTON event when a media button action occurs, with Intent.EXTRA_KEY_EVENT added and holding the key code of the media button that was pressed.
Deprecated:Use MediaSession.setMediaButtonReceiver(PendingIntent) instead.
/**
     * Register a component to be the sole receiver of MEDIA_BUTTON intents.  This is like
     * {@link #registerMediaButtonEventReceiver(android.content.ComponentName)}, but allows
     * the buttons to go to any PendingIntent.  Note that you should only use this form if
     * you know you will continue running for the full time until unregistering the
     * PendingIntent.
     * @param eventReceiver target that will receive media button intents.  The PendingIntent
     * will be sent an {@link Intent#ACTION_MEDIA_BUTTON} event when a media button action
     * occurs, with {@link Intent#EXTRA_KEY_EVENT} added and holding the key code of the
     * media button that was pressed.
     * @deprecated Use {@link MediaSession#setMediaButtonReceiver(PendingIntent)} instead.
     */
    @Deprecated
    public void registerMediaButtonEventReceiver(PendingIntent eventReceiver) {
        if (eventReceiver == null) {
            return;
        }
        registerMediaButtonIntent(eventReceiver, null);
    }

    
@hide
no-op if (pi == null) or (eventReceiver == null)
/**
     * @hide
     * no-op if (pi == null) or (eventReceiver == null)
     */
    public void registerMediaButtonIntent(PendingIntent pi, ComponentName eventReceiver) {
        if (pi == null) {
            Log.e(TAG, "Cannot call registerMediaButtonIntent() with a null parameter");
            return;
        }
        MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
        helper.addMediaButtonListener(pi, eventReceiver, getContext());
    }

    
Unregister the receiver of MEDIA_BUTTON intents.

Params:
Deprecated:Use MediaSession instead.
/**
     * Unregister the receiver of MEDIA_BUTTON intents.
     * @param eventReceiver identifier of a {@link android.content.BroadcastReceiver}
     *      that was registered with {@link #registerMediaButtonEventReceiver(ComponentName)}.
     * @deprecated Use {@link MediaSession} instead.
     */
    @Deprecated
    public void unregisterMediaButtonEventReceiver(ComponentName eventReceiver) {
        if (eventReceiver == null) {
            return;
        }
        // construct a PendingIntent for the media button and unregister it
        Intent mediaButtonIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
        //     the associated intent will be handled by the component being registered
        mediaButtonIntent.setComponent(eventReceiver);
        PendingIntent pi = PendingIntent.getBroadcast(getContext(),
                0/*requestCode, ignored*/, mediaButtonIntent, 0/*flags*/);
        unregisterMediaButtonIntent(pi);
    }

    
Unregister the receiver of MEDIA_BUTTON intents.

Params:
Deprecated:Use MediaSession instead.
/**
     * Unregister the receiver of MEDIA_BUTTON intents.
     * @param eventReceiver same PendingIntent that was registed with
     *      {@link #registerMediaButtonEventReceiver(PendingIntent)}.
     * @deprecated Use {@link MediaSession} instead.
     */
    @Deprecated
    public void unregisterMediaButtonEventReceiver(PendingIntent eventReceiver) {
        if (eventReceiver == null) {
            return;
        }
        unregisterMediaButtonIntent(eventReceiver);
    }

    
@hide
/**
     * @hide
     */
    public void unregisterMediaButtonIntent(PendingIntent pi) {
        MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
        helper.removeMediaButtonListener(pi);
    }

    
Registers the remote control client for providing information to display on the remote
controls.

Params:
  • rcClient – The remote control client from which remote controls will receive
     information to display.
See Also:
Deprecated:Use MediaSession instead.
/**
     * Registers the remote control client for providing information to display on the remote
     * controls.
     * @param rcClient The remote control client from which remote controls will receive
     *      information to display.
     * @see RemoteControlClient
     * @deprecated Use {@link MediaSession} instead.
     */
    @Deprecated
    public void registerRemoteControlClient(RemoteControlClient rcClient) {
        if ((rcClient == null) || (rcClient.getRcMediaIntent() == null)) {
            return;
        }
        rcClient.registerWithSession(MediaSessionLegacyHelper.getHelper(getContext()));
    }

    
Unregisters the remote control client that was providing information to display on the
remote controls.

Params:
  • rcClient – The remote control client to unregister.
See Also:
Deprecated:Use MediaSession instead.
/**
     * Unregisters the remote control client that was providing information to display on the
     * remote controls.
     * @param rcClient The remote control client to unregister.
     * @see #registerRemoteControlClient(RemoteControlClient)
     * @deprecated Use {@link MediaSession} instead.
     */
    @Deprecated
    public void unregisterRemoteControlClient(RemoteControlClient rcClient) {
        if ((rcClient == null) || (rcClient.getRcMediaIntent() == null)) {
            return;
        }
        rcClient.unregisterWithSession(MediaSessionLegacyHelper.getHelper(getContext()));
    }

    
Registers a RemoteController instance for it to receive media metadata updates and playback state information from applications using RemoteControlClient, and control their playback. 
 Registration requires the OnClientUpdateListener listener to be one of the enabled notification listeners (see NotificationListenerService). 
Params:
  • rctlr – the object to register.
Returns:true if the RemoteController was successfully registered, false if an error occurred, due to an internal system error, or insufficient permissions.
Deprecated:Use MediaSessionManager.addOnActiveSessionsChangedListener(OnActiveSessionsChangedListener, ComponentName) and MediaController instead.
/**
     * Registers a {@link RemoteController} instance for it to receive media
     * metadata updates and playback state information from applications using
     * {@link RemoteControlClient}, and control their playback.
     * <p>
     * Registration requires the {@link RemoteController.OnClientUpdateListener} listener to be
     * one of the enabled notification listeners (see
     * {@link android.service.notification.NotificationListenerService}).
     *
     * @param rctlr the object to register.
     * @return true if the {@link RemoteController} was successfully registered,
     *         false if an error occurred, due to an internal system error, or
     *         insufficient permissions.
     * @deprecated Use
     *             {@link MediaSessionManager#addOnActiveSessionsChangedListener(android.media.session.MediaSessionManager.OnActiveSessionsChangedListener, ComponentName)}
     *             and {@link MediaController} instead.
     */
    @Deprecated
    public boolean registerRemoteController(RemoteController rctlr) {
        if (rctlr == null) {
            return false;
        }
        rctlr.startListeningToSessions();
        return true;
    }

    
Unregisters a RemoteController, causing it to no longer receive media metadata and playback state information, and no longer be capable of controlling playback. 
Params:
  • rctlr – the object to unregister.
Deprecated:Use MediaSessionManager.removeOnActiveSessionsChangedListener(OnActiveSessionsChangedListener) instead.
/**
     * Unregisters a {@link RemoteController}, causing it to no longer receive
     * media metadata and playback state information, and no longer be capable
     * of controlling playback.
     *
     * @param rctlr the object to unregister.
     * @deprecated Use
     *             {@link MediaSessionManager#removeOnActiveSessionsChangedListener(android.media.session.MediaSessionManager.OnActiveSessionsChangedListener)}
     *             instead.
     */
    @Deprecated
    public void unregisterRemoteController(RemoteController rctlr) {
        if (rctlr == null) {
            return;
        }
        rctlr.stopListeningToSessions();
    }


    //====================================================================
    // Audio policy
    
Params:
@hide Register the given AudioPolicy. This call is synchronous and blocks until the registration process successfully completed or failed to complete.
Returns:ERROR if there was an error communicating with the registration service or if the user doesn't have the required MODIFY_AUDIO_ROUTING.MODIFY_AUDIO_ROUTING permission, SUCCESS otherwise.
/**
     * @hide
     * Register the given {@link AudioPolicy}.
     * This call is synchronous and blocks until the registration process successfully completed
     * or failed to complete.
     * @param policy the non-null {@link AudioPolicy} to register.
     * @return {@link #ERROR} if there was an error communicating with the registration service
     *    or if the user doesn't have the required
     *    {@link android.Manifest.permission#MODIFY_AUDIO_ROUTING} permission,
     *    {@link #SUCCESS} otherwise.
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
    public int registerAudioPolicy(@NonNull AudioPolicy policy) {
        if (policy == null) {
            throw new IllegalArgumentException("Illegal null AudioPolicy argument");
        }
        final IAudioService service = getService();
        try {
            String regId = service.registerAudioPolicy(policy.getConfig(), policy.cb(),
                    policy.hasFocusListener(), policy.isFocusPolicy(), policy.isVolumeController());
            if (regId == null) {
                return ERROR;
            } else {
                policy.setRegistration(regId);
            }
            // successful registration
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
        return SUCCESS;
    }

    
Params:
@hide
/**
     * @hide
     * @param policy the non-null {@link AudioPolicy} to unregister.
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
    public void unregisterAudioPolicyAsync(@NonNull AudioPolicy policy) {
        if (policy == null) {
            throw new IllegalArgumentException("Illegal null AudioPolicy argument");
        }
        final IAudioService service = getService();
        try {
            service.unregisterAudioPolicyAsync(policy.cb());
            policy.setRegistration(null);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    //====================================================================
    // Notification of playback activity & playback configuration
    
Interface for receiving update notifications about the playback activity on the system. Extend this abstract class and register it with AudioManager.registerAudioPlaybackCallback(AudioPlaybackCallback, Handler) to be notified. Use AudioManager.getActivePlaybackConfigurations() to query the current configuration. 
See Also:
/**
     * Interface for receiving update notifications about the playback activity on the system.
     * Extend this abstract class and register it with
     * {@link AudioManager#registerAudioPlaybackCallback(AudioPlaybackCallback, Handler)}
     * to be notified.
     * Use {@link AudioManager#getActivePlaybackConfigurations()} to query the current
     * configuration.
     * @see AudioPlaybackConfiguration
     */
    public static abstract class AudioPlaybackCallback {
        
Called whenever the playback activity and configuration has changed.

Params:
/**
         * Called whenever the playback activity and configuration has changed.
         * @param configs list containing the results of
         *      {@link AudioManager#getActivePlaybackConfigurations()}.
         */
        public void onPlaybackConfigChanged(List<AudioPlaybackConfiguration> configs) {}
    }

    private static class AudioPlaybackCallbackInfo {
        final AudioPlaybackCallback mCb;
        final Handler mHandler;
        AudioPlaybackCallbackInfo(AudioPlaybackCallback cb, Handler handler) {
            mCb = cb;
            mHandler = handler;
        }
    }

    private final static class PlaybackConfigChangeCallbackData {
        final AudioPlaybackCallback mCb;
        final List<AudioPlaybackConfiguration> mConfigs;

        PlaybackConfigChangeCallbackData(AudioPlaybackCallback cb,
                List<AudioPlaybackConfiguration> configs) {
            mCb = cb;
            mConfigs = configs;
        }
    }

    
Register a callback to be notified of audio playback changes through AudioPlaybackCallback 
Params:
  • cb – non-null callback to register
  • handler – the Handler object for the thread on which to execute the callback. If null, the Handler associated with the main Looper will be used.
/**
     * Register a callback to be notified of audio playback changes through
     * {@link AudioPlaybackCallback}
     * @param cb non-null callback to register
     * @param handler the {@link Handler} object for the thread on which to execute
     * the callback. If <code>null</code>, the {@link Handler} associated with the main
     * {@link Looper} will be used.
     */
    public void registerAudioPlaybackCallback(@NonNull AudioPlaybackCallback cb, Handler handler)
    {
        if (cb == null) {
            throw new IllegalArgumentException("Illegal null AudioPlaybackCallback argument");
        }

        synchronized(mPlaybackCallbackLock) {
            // lazy initialization of the list of playback callbacks
            if (mPlaybackCallbackList == null) {
                mPlaybackCallbackList = new ArrayList<AudioPlaybackCallbackInfo>();
            }
            final int oldCbCount = mPlaybackCallbackList.size();
            if (!hasPlaybackCallback_sync(cb)) {
                mPlaybackCallbackList.add(new AudioPlaybackCallbackInfo(cb,
                        new ServiceEventHandlerDelegate(handler).getHandler()));
                final int newCbCount = mPlaybackCallbackList.size();
                if ((oldCbCount == 0) && (newCbCount > 0)) {
                    // register binder for callbacks
                    try {
                        getService().registerPlaybackCallback(mPlayCb);
                    } catch (RemoteException e) {
                        throw e.rethrowFromSystemServer();
                    }
                }
            } else {
                Log.w(TAG, "attempt to call registerAudioPlaybackCallback() on a previously"
                        + "registered callback");
            }
        }
    }

    
Unregister an audio playback callback previously registered with registerAudioPlaybackCallback(AudioPlaybackCallback, Handler). 
Params:
  • cb – non-null callback to unregister
/**
     * Unregister an audio playback callback previously registered with
     * {@link #registerAudioPlaybackCallback(AudioPlaybackCallback, Handler)}.
     * @param cb non-null callback to unregister
     */
    public void unregisterAudioPlaybackCallback(@NonNull AudioPlaybackCallback cb) {
        if (cb == null) {
            throw new IllegalArgumentException("Illegal null AudioPlaybackCallback argument");
        }
        synchronized(mPlaybackCallbackLock) {
            if (mPlaybackCallbackList == null) {
                Log.w(TAG, "attempt to call unregisterAudioPlaybackCallback() on a callback"
                        + " that was never registered");
                return;
            }
            final int oldCbCount = mPlaybackCallbackList.size();
            if (removePlaybackCallback_sync(cb)) {
                final int newCbCount = mPlaybackCallbackList.size();
                if ((oldCbCount > 0) && (newCbCount == 0)) {
                    // unregister binder for callbacks
                    try {
                        getService().unregisterPlaybackCallback(mPlayCb);
                    } catch (RemoteException e) {
                        throw e.rethrowFromSystemServer();
                    }
                }
            } else {
                Log.w(TAG, "attempt to call unregisterAudioPlaybackCallback() on a callback"
                        + " already unregistered or never registered");
            }
        }
    }

    
Returns the current active audio playback configurations of the device

See Also:
Returns:a non-null list of playback configurations. An empty list indicates there is no
    playback active when queried.
/**
     * Returns the current active audio playback configurations of the device
     * @return a non-null list of playback configurations. An empty list indicates there is no
     *     playback active when queried.
     * @see AudioPlaybackConfiguration
     */
    public @NonNull List<AudioPlaybackConfiguration> getActivePlaybackConfigurations() {
        final IAudioService service = getService();
        try {
            return service.getActivePlaybackConfigurations();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
All operations on this list are sync'd on mPlaybackCallbackLock. List is lazy-initialized in registerAudioPlaybackCallback(AudioPlaybackCallback, Handler). List can be null. 
/**
     * All operations on this list are sync'd on mPlaybackCallbackLock.
     * List is lazy-initialized in
     * {@link #registerAudioPlaybackCallback(AudioPlaybackCallback, Handler)}.
     * List can be null.
     */
    private List<AudioPlaybackCallbackInfo> mPlaybackCallbackList;
    private final Object mPlaybackCallbackLock = new Object();

    
Must be called synchronized on mPlaybackCallbackLock

/**
     * Must be called synchronized on mPlaybackCallbackLock
     */
    private boolean hasPlaybackCallback_sync(@NonNull AudioPlaybackCallback cb) {
        if (mPlaybackCallbackList != null) {
            for (int i=0 ; i < mPlaybackCallbackList.size() ; i++) {
                if (cb.equals(mPlaybackCallbackList.get(i).mCb)) {
                    return true;
                }
            }
        }
        return false;
    }

    
Must be called synchronized on mPlaybackCallbackLock

/**
     * Must be called synchronized on mPlaybackCallbackLock
     */
    private boolean removePlaybackCallback_sync(@NonNull AudioPlaybackCallback cb) {
        if (mPlaybackCallbackList != null) {
            for (int i=0 ; i < mPlaybackCallbackList.size() ; i++) {
                if (cb.equals(mPlaybackCallbackList.get(i).mCb)) {
                    mPlaybackCallbackList.remove(i);
                    return true;
                }
            }
        }
        return false;
    }

    private final IPlaybackConfigDispatcher mPlayCb = new IPlaybackConfigDispatcher.Stub() {
        @Override
        public void dispatchPlaybackConfigChange(List<AudioPlaybackConfiguration> configs,
                boolean flush) {
            if (flush) {
                Binder.flushPendingCommands();
            }
            synchronized(mPlaybackCallbackLock) {
                if (mPlaybackCallbackList != null) {
                    for (int i=0 ; i < mPlaybackCallbackList.size() ; i++) {
                        final AudioPlaybackCallbackInfo arci = mPlaybackCallbackList.get(i);
                        if (arci.mHandler != null) {
                            final Message m = arci.mHandler.obtainMessage(
                                    MSSG_PLAYBACK_CONFIG_CHANGE/*what*/,
                                    new PlaybackConfigChangeCallbackData(arci.mCb, configs)/*obj*/);
                            arci.mHandler.sendMessage(m);
                        }
                    }
                }
            }
        }

    };

    //====================================================================
    // Notification of recording activity & recording configuration
    
Interface for receiving update notifications about the recording configuration. Extend this abstract class and register it with AudioManager.registerAudioRecordingCallback(AudioRecordingCallback, Handler) to be notified. Use AudioManager.getActiveRecordingConfigurations() to query the current configuration. 
See Also:
/**
     * Interface for receiving update notifications about the recording configuration. Extend
     * this abstract class and register it with
     * {@link AudioManager#registerAudioRecordingCallback(AudioRecordingCallback, Handler)}
     * to be notified.
     * Use {@link AudioManager#getActiveRecordingConfigurations()} to query the current
     * configuration.
     * @see AudioRecordingConfiguration
     */
    public static abstract class AudioRecordingCallback {
        
Called whenever the device recording configuration has changed.

Params:
/**
         * Called whenever the device recording configuration has changed.
         * @param configs list containing the results of
         *      {@link AudioManager#getActiveRecordingConfigurations()}.
         */
        public void onRecordingConfigChanged(List<AudioRecordingConfiguration> configs) {}
    }

    private static class AudioRecordingCallbackInfo {
        final AudioRecordingCallback mCb;
        final Handler mHandler;
        AudioRecordingCallbackInfo(AudioRecordingCallback cb, Handler handler) {
            mCb = cb;
            mHandler = handler;
        }
    }

    private final static class RecordConfigChangeCallbackData {
        final AudioRecordingCallback mCb;
        final List<AudioRecordingConfiguration> mConfigs;

        RecordConfigChangeCallbackData(AudioRecordingCallback cb,
                List<AudioRecordingConfiguration> configs) {
            mCb = cb;
            mConfigs = configs;
        }
    }

    
Register a callback to be notified of audio recording changes through AudioRecordingCallback 
Params:
  • cb – non-null callback to register
  • handler – the Handler object for the thread on which to execute the callback. If null, the Handler associated with the main Looper will be used.
/**
     * Register a callback to be notified of audio recording changes through
     * {@link AudioRecordingCallback}
     * @param cb non-null callback to register
     * @param handler the {@link Handler} object for the thread on which to execute
     * the callback. If <code>null</code>, the {@link Handler} associated with the main
     * {@link Looper} will be used.
     */
    public void registerAudioRecordingCallback(@NonNull AudioRecordingCallback cb, Handler handler)
    {
        if (cb == null) {
            throw new IllegalArgumentException("Illegal null AudioRecordingCallback argument");
        }

        synchronized(mRecordCallbackLock) {
            // lazy initialization of the list of recording callbacks
            if (mRecordCallbackList == null) {
                mRecordCallbackList = new ArrayList<AudioRecordingCallbackInfo>();
            }
            final int oldCbCount = mRecordCallbackList.size();
            if (!hasRecordCallback_sync(cb)) {
                mRecordCallbackList.add(new AudioRecordingCallbackInfo(cb,
                        new ServiceEventHandlerDelegate(handler).getHandler()));
                final int newCbCount = mRecordCallbackList.size();
                if ((oldCbCount == 0) && (newCbCount > 0)) {
                    // register binder for callbacks
                    final IAudioService service = getService();
                    try {
                        service.registerRecordingCallback(mRecCb);
                    } catch (RemoteException e) {
                        throw e.rethrowFromSystemServer();
                    }
                }
            } else {
                Log.w(TAG, "attempt to call registerAudioRecordingCallback() on a previously"
                        + "registered callback");
            }
        }
    }

    
Unregister an audio recording callback previously registered with registerAudioRecordingCallback(AudioRecordingCallback, Handler). 
Params:
  • cb – non-null callback to unregister
/**
     * Unregister an audio recording callback previously registered with
     * {@link #registerAudioRecordingCallback(AudioRecordingCallback, Handler)}.
     * @param cb non-null callback to unregister
     */
    public void unregisterAudioRecordingCallback(@NonNull AudioRecordingCallback cb) {
        if (cb == null) {
            throw new IllegalArgumentException("Illegal null AudioRecordingCallback argument");
        }
        synchronized(mRecordCallbackLock) {
            if (mRecordCallbackList == null) {
                return;
            }
            final int oldCbCount = mRecordCallbackList.size();
            if (removeRecordCallback_sync(cb)) {
                final int newCbCount = mRecordCallbackList.size();
                if ((oldCbCount > 0) && (newCbCount == 0)) {
                    // unregister binder for callbacks
                    final IAudioService service = getService();
                    try {
                        service.unregisterRecordingCallback(mRecCb);
                    } catch (RemoteException e) {
                        throw e.rethrowFromSystemServer();
                    }
                }
            } else {
                Log.w(TAG, "attempt to call unregisterAudioRecordingCallback() on a callback"
                        + " already unregistered or never registered");
            }
        }
    }

    
Returns the current active audio recording configurations of the device.

See Also:
Returns:a non-null list of recording configurations. An empty list indicates there is
    no recording active when queried.
/**
     * Returns the current active audio recording configurations of the device.
     * @return a non-null list of recording configurations. An empty list indicates there is
     *     no recording active when queried.
     * @see AudioRecordingConfiguration
     */
    public @NonNull List<AudioRecordingConfiguration> getActiveRecordingConfigurations() {
        final IAudioService service = getService();
        try {
            return service.getActiveRecordingConfigurations();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    /**
     * constants for the recording events, to keep in sync
     * with frameworks/av/include/media/AudioPolicy.h
     */
    
@hide
/** @hide */
    public final static int RECORD_CONFIG_EVENT_START = 1;
    
@hide
/** @hide */
    public final static int RECORD_CONFIG_EVENT_STOP = 0;

    
All operations on this list are sync'd on mRecordCallbackLock. List is lazy-initialized in registerAudioRecordingCallback(AudioRecordingCallback, Handler). List can be null. 
/**
     * All operations on this list are sync'd on mRecordCallbackLock.
     * List is lazy-initialized in
     * {@link #registerAudioRecordingCallback(AudioRecordingCallback, Handler)}.
     * List can be null.
     */
    private List<AudioRecordingCallbackInfo> mRecordCallbackList;
    private final Object mRecordCallbackLock = new Object();

    
Must be called synchronized on mRecordCallbackLock

/**
     * Must be called synchronized on mRecordCallbackLock
     */
    private boolean hasRecordCallback_sync(@NonNull AudioRecordingCallback cb) {
        if (mRecordCallbackList != null) {
            for (int i=0 ; i < mRecordCallbackList.size() ; i++) {
                if (cb.equals(mRecordCallbackList.get(i).mCb)) {
                    return true;
                }
            }
        }
        return false;
    }

    
Must be called synchronized on mRecordCallbackLock

/**
     * Must be called synchronized on mRecordCallbackLock
     */
    private boolean removeRecordCallback_sync(@NonNull AudioRecordingCallback cb) {
        if (mRecordCallbackList != null) {
            for (int i=0 ; i < mRecordCallbackList.size() ; i++) {
                if (cb.equals(mRecordCallbackList.get(i).mCb)) {
                    mRecordCallbackList.remove(i);
                    return true;
                }
            }
        }
        return false;
    }

    private final IRecordingConfigDispatcher mRecCb = new IRecordingConfigDispatcher.Stub() {
        @Override
        public void dispatchRecordingConfigChange(List<AudioRecordingConfiguration> configs) {
            synchronized(mRecordCallbackLock) {
                if (mRecordCallbackList != null) {
                    for (int i=0 ; i < mRecordCallbackList.size() ; i++) {
                        final AudioRecordingCallbackInfo arci = mRecordCallbackList.get(i);
                        if (arci.mHandler != null) {
                            final Message m = arci.mHandler.obtainMessage(
                                    MSSG_RECORDING_CONFIG_CHANGE/*what*/,
                                    new RecordConfigChangeCallbackData(arci.mCb, configs)/*obj*/);
                            arci.mHandler.sendMessage(m);
                        }
                    }
                }
            }
        }

    };

    //=====================================================================

    
 @hide
 Reload audio settings. This method is called by Settings backup
 agent when audio settings are restored and causes the AudioService
 to read and apply restored settings.

/**
     *  @hide
     *  Reload audio settings. This method is called by Settings backup
     *  agent when audio settings are restored and causes the AudioService
     *  to read and apply restored settings.
     */
    public void reloadAudioSettings() {
        final IAudioService service = getService();
        try {
            service.reloadAudioSettings();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
@hide
Notifies AudioService that it is connected to an A2DP device that supports absolute volume,
so that AudioService can send volume change events to the A2DP device, rather than handling
them.
/**
     * @hide
     * Notifies AudioService that it is connected to an A2DP device that supports absolute volume,
     * so that AudioService can send volume change events to the A2DP device, rather than handling
     * them.
     */
    public void avrcpSupportsAbsoluteVolume(String address, boolean support) {
        final IAudioService service = getService();
        try {
            service.avrcpSupportsAbsoluteVolume(address, support);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

     
{@hide}

/**
      * {@hide}
      */
     private final IBinder mICallBack = new Binder();

    
Checks whether the phone is in silent mode, with or without vibrate.

See Also:
Returns:true if phone is in silent mode, with or without vibrate.
@hidepending API Council approval
/**
     * Checks whether the phone is in silent mode, with or without vibrate.
     *
     * @return true if phone is in silent mode, with or without vibrate.
     *
     * @see #getRingerMode()
     *
     * @hide pending API Council approval
     */
    public boolean isSilentMode() {
        int ringerMode = getRingerMode();
        boolean silentMode =
            (ringerMode == RINGER_MODE_SILENT) ||
            (ringerMode == RINGER_MODE_VIBRATE);
        return silentMode;
    }

    // This section re-defines new output device constants from AudioSystem, because the AudioSystem
    // class is not used by other parts of the framework, which instead use definitions and methods
    // from AudioManager. AudioSystem is an internal class used by AudioManager and AudioService.

    
@hide
The audio device code for representing "no device."
/** @hide
     * The audio device code for representing "no device." */
    public static final int DEVICE_NONE = AudioSystem.DEVICE_NONE;
    
@hide The audio output device code for the small speaker at the front of the device used when placing calls. Does not refer to an in-ear headphone without attached microphone, such as earbuds, earphones, or in-ear monitors (IEM). Those would be handled as a DEVICE_OUT_WIRED_HEADPHONE.
/** @hide
     *  The audio output device code for the small speaker at the front of the device used
     *  when placing calls.  Does not refer to an in-ear headphone without attached microphone,
     *  such as earbuds, earphones, or in-ear monitors (IEM). Those would be handled as a
     *  {@link #DEVICE_OUT_WIRED_HEADPHONE}.
     */
    public static final int DEVICE_OUT_EARPIECE = AudioSystem.DEVICE_OUT_EARPIECE;
    
@hide
 The audio output device code for the built-in speaker
/** @hide
     *  The audio output device code for the built-in speaker */
    public static final int DEVICE_OUT_SPEAKER = AudioSystem.DEVICE_OUT_SPEAKER;
    
@hide
The audio output device code for a wired headset with attached microphone
/** @hide
     * The audio output device code for a wired headset with attached microphone */
    public static final int DEVICE_OUT_WIRED_HEADSET = AudioSystem.DEVICE_OUT_WIRED_HEADSET;
    
@hide
The audio output device code for a wired headphone without attached microphone
/** @hide
     * The audio output device code for a wired headphone without attached microphone */
    public static final int DEVICE_OUT_WIRED_HEADPHONE = AudioSystem.DEVICE_OUT_WIRED_HEADPHONE;
    
@hide
The audio output device code for a USB headphone with attached microphone
/** @hide
     * The audio output device code for a USB headphone with attached microphone */
    public static final int DEVICE_OUT_USB_HEADSET = AudioSystem.DEVICE_OUT_USB_HEADSET;
    
@hide
The audio output device code for generic Bluetooth SCO, for voice
/** @hide
     * The audio output device code for generic Bluetooth SCO, for voice */
    public static final int DEVICE_OUT_BLUETOOTH_SCO = AudioSystem.DEVICE_OUT_BLUETOOTH_SCO;
    
@hide
The audio output device code for Bluetooth SCO Headset Profile (HSP) and
Hands-Free Profile (HFP), for voice
/** @hide
     * The audio output device code for Bluetooth SCO Headset Profile (HSP) and
     * Hands-Free Profile (HFP), for voice
     */
    public static final int DEVICE_OUT_BLUETOOTH_SCO_HEADSET =
            AudioSystem.DEVICE_OUT_BLUETOOTH_SCO_HEADSET;
    
@hide
The audio output device code for Bluetooth SCO car audio, for voice
/** @hide
     * The audio output device code for Bluetooth SCO car audio, for voice */
    public static final int DEVICE_OUT_BLUETOOTH_SCO_CARKIT =
            AudioSystem.DEVICE_OUT_BLUETOOTH_SCO_CARKIT;
    
@hide
The audio output device code for generic Bluetooth A2DP, for music
/** @hide
     * The audio output device code for generic Bluetooth A2DP, for music */
    public static final int DEVICE_OUT_BLUETOOTH_A2DP = AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP;
    
@hide
The audio output device code for Bluetooth A2DP headphones, for music
/** @hide
     * The audio output device code for Bluetooth A2DP headphones, for music */
    public static final int DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES =
            AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES;
    
@hide
The audio output device code for Bluetooth A2DP external speaker, for music
/** @hide
     * The audio output device code for Bluetooth A2DP external speaker, for music */
    public static final int DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER =
            AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER;
    
@hide The audio output device code for S/PDIF (legacy) or HDMI Deprecated: replaced by DEVICE_OUT_HDMI
/** @hide
     * The audio output device code for S/PDIF (legacy) or HDMI
     * Deprecated: replaced by {@link #DEVICE_OUT_HDMI} */
    public static final int DEVICE_OUT_AUX_DIGITAL = AudioSystem.DEVICE_OUT_AUX_DIGITAL;
    
@hide
The audio output device code for HDMI
/** @hide
     * The audio output device code for HDMI */
    public static final int DEVICE_OUT_HDMI = AudioSystem.DEVICE_OUT_HDMI;
    
@hide
The audio output device code for an analog wired headset attached via a
 docking station
/** @hide
     * The audio output device code for an analog wired headset attached via a
     *  docking station
     */
    public static final int DEVICE_OUT_ANLG_DOCK_HEADSET = AudioSystem.DEVICE_OUT_ANLG_DOCK_HEADSET;
    
@hide
The audio output device code for a digital wired headset attached via a
 docking station
/** @hide
     * The audio output device code for a digital wired headset attached via a
     *  docking station
     */
    public static final int DEVICE_OUT_DGTL_DOCK_HEADSET = AudioSystem.DEVICE_OUT_DGTL_DOCK_HEADSET;
    
@hide
The audio output device code for a USB audio accessory. The accessory is in USB host
mode and the Android device in USB device mode
/** @hide
     * The audio output device code for a USB audio accessory. The accessory is in USB host
     * mode and the Android device in USB device mode
     */
    public static final int DEVICE_OUT_USB_ACCESSORY = AudioSystem.DEVICE_OUT_USB_ACCESSORY;
    
@hide
The audio output device code for a USB audio device. The device is in USB device
mode and the Android device in USB host mode
/** @hide
     * The audio output device code for a USB audio device. The device is in USB device
     * mode and the Android device in USB host mode
     */
    public static final int DEVICE_OUT_USB_DEVICE = AudioSystem.DEVICE_OUT_USB_DEVICE;
    
@hide
The audio output device code for projection output.
/** @hide
     * The audio output device code for projection output.
     */
    public static final int DEVICE_OUT_REMOTE_SUBMIX = AudioSystem.DEVICE_OUT_REMOTE_SUBMIX;
    
@hide
The audio output device code the telephony voice TX path.
/** @hide
     * The audio output device code the telephony voice TX path.
     */
    public static final int DEVICE_OUT_TELEPHONY_TX = AudioSystem.DEVICE_OUT_TELEPHONY_TX;
    
@hide
The audio output device code for an analog jack with line impedance detected.
/** @hide
     * The audio output device code for an analog jack with line impedance detected.
     */
    public static final int DEVICE_OUT_LINE = AudioSystem.DEVICE_OUT_LINE;
    
@hide
The audio output device code for HDMI Audio Return Channel.
/** @hide
     * The audio output device code for HDMI Audio Return Channel.
     */
    public static final int DEVICE_OUT_HDMI_ARC = AudioSystem.DEVICE_OUT_HDMI_ARC;
    
@hide
The audio output device code for S/PDIF digital connection.
/** @hide
     * The audio output device code for S/PDIF digital connection.
     */
    public static final int DEVICE_OUT_SPDIF = AudioSystem.DEVICE_OUT_SPDIF;
    
@hide
The audio output device code for built-in FM transmitter.
/** @hide
     * The audio output device code for built-in FM transmitter.
     */
    public static final int DEVICE_OUT_FM = AudioSystem.DEVICE_OUT_FM;
    
@hide This is not used as a returned value from getDevicesForStream, but could be used in the future in a set method to select whatever default device is chosen by the platform-specific implementation.
/** @hide
     * This is not used as a returned value from {@link #getDevicesForStream}, but could be
     *  used in the future in a set method to select whatever default device is chosen by the
     *  platform-specific implementation.
     */
    public static final int DEVICE_OUT_DEFAULT = AudioSystem.DEVICE_OUT_DEFAULT;

    
@hide
The audio input device code for default built-in microphone
/** @hide
     * The audio input device code for default built-in microphone
     */
    public static final int DEVICE_IN_BUILTIN_MIC = AudioSystem.DEVICE_IN_BUILTIN_MIC;
    
@hide
The audio input device code for a Bluetooth SCO headset
/** @hide
     * The audio input device code for a Bluetooth SCO headset
     */
    public static final int DEVICE_IN_BLUETOOTH_SCO_HEADSET =
                                    AudioSystem.DEVICE_IN_BLUETOOTH_SCO_HEADSET;
    
@hide
The audio input device code for wired headset microphone
/** @hide
     * The audio input device code for wired headset microphone
     */
    public static final int DEVICE_IN_WIRED_HEADSET =
                                    AudioSystem.DEVICE_IN_WIRED_HEADSET;
    
@hide
The audio input device code for HDMI
/** @hide
     * The audio input device code for HDMI
     */
    public static final int DEVICE_IN_HDMI =
                                    AudioSystem.DEVICE_IN_HDMI;
    
@hide
The audio input device code for telephony voice RX path
/** @hide
     * The audio input device code for telephony voice RX path
     */
    public static final int DEVICE_IN_TELEPHONY_RX =
                                    AudioSystem.DEVICE_IN_TELEPHONY_RX;
    
@hide
The audio input device code for built-in microphone pointing to the back
/** @hide
     * The audio input device code for built-in microphone pointing to the back
     */
    public static final int DEVICE_IN_BACK_MIC =
                                    AudioSystem.DEVICE_IN_BACK_MIC;
    
@hide
The audio input device code for analog from a docking station
/** @hide
     * The audio input device code for analog from a docking station
     */
    public static final int DEVICE_IN_ANLG_DOCK_HEADSET =
                                    AudioSystem.DEVICE_IN_ANLG_DOCK_HEADSET;
    
@hide
The audio input device code for digital from a docking station
/** @hide
     * The audio input device code for digital from a docking station
     */
    public static final int DEVICE_IN_DGTL_DOCK_HEADSET =
                                    AudioSystem.DEVICE_IN_DGTL_DOCK_HEADSET;
    
@hide
The audio input device code for a USB audio accessory. The accessory is in USB host
mode and the Android device in USB device mode
/** @hide
     * The audio input device code for a USB audio accessory. The accessory is in USB host
     * mode and the Android device in USB device mode
     */
    public static final int DEVICE_IN_USB_ACCESSORY =
                                    AudioSystem.DEVICE_IN_USB_ACCESSORY;
    
@hide
The audio input device code for a USB audio device. The device is in USB device
mode and the Android device in USB host mode
/** @hide
     * The audio input device code for a USB audio device. The device is in USB device
     * mode and the Android device in USB host mode
     */
    public static final int DEVICE_IN_USB_DEVICE =
                                    AudioSystem.DEVICE_IN_USB_DEVICE;
    
@hide
The audio input device code for a FM radio tuner
/** @hide
     * The audio input device code for a FM radio tuner
     */
    public static final int DEVICE_IN_FM_TUNER = AudioSystem.DEVICE_IN_FM_TUNER;
    
@hide
The audio input device code for a TV tuner
/** @hide
     * The audio input device code for a TV tuner
     */
    public static final int DEVICE_IN_TV_TUNER = AudioSystem.DEVICE_IN_TV_TUNER;
    
@hide
The audio input device code for an analog jack with line impedance detected
/** @hide
     * The audio input device code for an analog jack with line impedance detected
     */
    public static final int DEVICE_IN_LINE = AudioSystem.DEVICE_IN_LINE;
    
@hide
The audio input device code for a S/PDIF digital connection
/** @hide
     * The audio input device code for a S/PDIF digital connection
     */
    public static final int DEVICE_IN_SPDIF = AudioSystem.DEVICE_IN_SPDIF;
    
@hide
The audio input device code for audio loopback
/** @hide
     * The audio input device code for audio loopback
     */
    public static final int DEVICE_IN_LOOPBACK = AudioSystem.DEVICE_IN_LOOPBACK;

    
Return true if the device code corresponds to an output device.

@hide
/**
     * Return true if the device code corresponds to an output device.
     * @hide
     */
    public static boolean isOutputDevice(int device)
    {
        return (device & AudioSystem.DEVICE_BIT_IN) == 0;
    }

    
Return true if the device code corresponds to an input device.

@hide
/**
     * Return true if the device code corresponds to an input device.
     * @hide
     */
    public static boolean isInputDevice(int device)
    {
        return (device & AudioSystem.DEVICE_BIT_IN) == AudioSystem.DEVICE_BIT_IN;
    }


    
Return the enabled devices for the specified output stream type.

Params:
Returns:The bit-mask "or" of audio output device codes for all enabled devices on this stream. Zero or more of DEVICE_OUT_EARPIECE, DEVICE_OUT_SPEAKER, DEVICE_OUT_WIRED_HEADSET, DEVICE_OUT_WIRED_HEADPHONE, DEVICE_OUT_BLUETOOTH_SCO, DEVICE_OUT_BLUETOOTH_SCO_HEADSET, DEVICE_OUT_BLUETOOTH_SCO_CARKIT, DEVICE_OUT_BLUETOOTH_A2DP, DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES, DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER, DEVICE_OUT_HDMI, DEVICE_OUT_ANLG_DOCK_HEADSET, DEVICE_OUT_DGTL_DOCK_HEADSET. DEVICE_OUT_USB_ACCESSORY. DEVICE_OUT_USB_DEVICE. DEVICE_OUT_REMOTE_SUBMIX. DEVICE_OUT_TELEPHONY_TX. DEVICE_OUT_LINE. DEVICE_OUT_HDMI_ARC. DEVICE_OUT_SPDIF. DEVICE_OUT_FM. DEVICE_OUT_DEFAULT is not used here. The implementation may support additional device codes beyond those listed, so the application should ignore any bits which it does not recognize. Note that the information may be imprecise when the implementation cannot distinguish whether a particular device is enabled. {@hide}
/**
     * Return the enabled devices for the specified output stream type.
     *
     * @param streamType The stream type to query. One of
     *            {@link #STREAM_VOICE_CALL},
     *            {@link #STREAM_SYSTEM},
     *            {@link #STREAM_RING},
     *            {@link #STREAM_MUSIC},
     *            {@link #STREAM_ALARM},
     *            {@link #STREAM_NOTIFICATION},
     *            {@link #STREAM_DTMF},
     *            {@link #STREAM_ACCESSIBILITY}.
     *
     * @return The bit-mask "or" of audio output device codes for all enabled devices on this
     *         stream. Zero or more of
     *            {@link #DEVICE_OUT_EARPIECE},
     *            {@link #DEVICE_OUT_SPEAKER},
     *            {@link #DEVICE_OUT_WIRED_HEADSET},
     *            {@link #DEVICE_OUT_WIRED_HEADPHONE},
     *            {@link #DEVICE_OUT_BLUETOOTH_SCO},
     *            {@link #DEVICE_OUT_BLUETOOTH_SCO_HEADSET},
     *            {@link #DEVICE_OUT_BLUETOOTH_SCO_CARKIT},
     *            {@link #DEVICE_OUT_BLUETOOTH_A2DP},
     *            {@link #DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES},
     *            {@link #DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER},
     *            {@link #DEVICE_OUT_HDMI},
     *            {@link #DEVICE_OUT_ANLG_DOCK_HEADSET},
     *            {@link #DEVICE_OUT_DGTL_DOCK_HEADSET}.
     *            {@link #DEVICE_OUT_USB_ACCESSORY}.
     *            {@link #DEVICE_OUT_USB_DEVICE}.
     *            {@link #DEVICE_OUT_REMOTE_SUBMIX}.
     *            {@link #DEVICE_OUT_TELEPHONY_TX}.
     *            {@link #DEVICE_OUT_LINE}.
     *            {@link #DEVICE_OUT_HDMI_ARC}.
     *            {@link #DEVICE_OUT_SPDIF}.
     *            {@link #DEVICE_OUT_FM}.
     *            {@link #DEVICE_OUT_DEFAULT} is not used here.
     *
     * The implementation may support additional device codes beyond those listed, so
     * the application should ignore any bits which it does not recognize.
     * Note that the information may be imprecise when the implementation
     * cannot distinguish whether a particular device is enabled.
     *
     * {@hide}
     */
    public int getDevicesForStream(int streamType) {
        switch (streamType) {
        case STREAM_VOICE_CALL:
        case STREAM_SYSTEM:
        case STREAM_RING:
        case STREAM_MUSIC:
        case STREAM_ALARM:
        case STREAM_NOTIFICATION:
        case STREAM_DTMF:
        case STREAM_ACCESSIBILITY:
            return AudioSystem.getDevicesForStream(streamType);
        default:
            return 0;
        }
    }

     
Indicate wired accessory connection state change.

Params:
  • device – type of device connected/disconnected (AudioManager.DEVICE_OUT_xxx)
  • state –  new connection state: 1 connected, 0 disconnected
  • name –   device name
{@hide}
/**
     * Indicate wired accessory connection state change.
     * @param device type of device connected/disconnected (AudioManager.DEVICE_OUT_xxx)
     * @param state  new connection state: 1 connected, 0 disconnected
     * @param name   device name
     * {@hide}
     */
    public void setWiredDeviceConnectionState(int type, int state, String address, String name) {
        final IAudioService service = getService();
        try {
            service.setWiredDeviceConnectionState(type, state, address, name,
                    mApplicationContext.getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

     
Indicate Hearing Aid connection state change and eventually suppress the ACTION_AUDIO_BECOMING_NOISY intent. 
Params:
  • device – Bluetooth device connected/disconnected
  • state – new connection state (BluetoothProfile.STATE_xxx)
  • musicDevice – Default get system volume for the connecting device. (either hearingaid or HEARING_AID)
  • suppressNoisyIntent – if true the ACTION_AUDIO_BECOMING_NOISY intent will not be sent.
Returns:a delay in ms that the caller should wait before broadcasting
BluetoothHearingAid.ACTION_CONNECTION_STATE_CHANGED intent.
{@hide}
/**
     * Indicate Hearing Aid connection state change and eventually suppress
     * the {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent.
     * @param device Bluetooth device connected/disconnected
     * @param state new connection state (BluetoothProfile.STATE_xxx)
     * @param musicDevice Default get system volume for the connecting device.
     * (either {@link android.bluetooth.BluetoothProfile.hearingaid} or
     * {@link android.bluetooth.BluetoothProfile.HEARING_AID})
     * @param suppressNoisyIntent if true the
     * {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent will not be sent.
     * @return a delay in ms that the caller should wait before broadcasting
     * BluetoothHearingAid.ACTION_CONNECTION_STATE_CHANGED intent.
     * {@hide}
     */
    public int setBluetoothHearingAidDeviceConnectionState(
                BluetoothDevice device, int state, boolean suppressNoisyIntent,
                int musicDevice) {
        final IAudioService service = getService();
        int delay = 0;
        try {
            delay = service.setBluetoothHearingAidDeviceConnectionState(device,
                state, suppressNoisyIntent, musicDevice);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
        return delay;
    }

     
Indicate A2DP source or sink connection state change.

Params:
  • device – Bluetooth device connected/disconnected
  • state –  new connection state (BluetoothProfile.STATE_xxx)
  • profile – profile for the A2DP device (either A2DP or A2DP_SINK)
Returns:a delay in ms that the caller should wait before broadcasting
BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED intent.
{@hide}
/**
     * Indicate A2DP source or sink connection state change.
     * @param device Bluetooth device connected/disconnected
     * @param state  new connection state (BluetoothProfile.STATE_xxx)
     * @param profile profile for the A2DP device
     * (either {@link android.bluetooth.BluetoothProfile.A2DP} or
     * {@link android.bluetooth.BluetoothProfile.A2DP_SINK})
     * @return a delay in ms that the caller should wait before broadcasting
     * BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED intent.
     * {@hide}
     */
    public int setBluetoothA2dpDeviceConnectionState(BluetoothDevice device, int state,
            int profile) {
        final IAudioService service = getService();
        int delay = 0;
        try {
            delay = service.setBluetoothA2dpDeviceConnectionState(device, state, profile);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
        return delay;
    }

     
Indicate A2DP source or sink connection state change and eventually suppress the ACTION_AUDIO_BECOMING_NOISY intent. 
Params:
  • device – Bluetooth device connected/disconnected
  • state –  new connection state (BluetoothProfile.STATE_xxx)
  • profile – profile for the A2DP device
  • a2dpVolume – New volume for the connecting device. Does nothing if disconnecting. (either A2DP or A2DP_SINK)
  • suppressNoisyIntent – if true the ACTION_AUDIO_BECOMING_NOISY intent will not be sent.
Returns:a delay in ms that the caller should wait before broadcasting
BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED intent.
{@hide}
/**
     * Indicate A2DP source or sink connection state change and eventually suppress
     * the {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent.
     * @param device Bluetooth device connected/disconnected
     * @param state  new connection state (BluetoothProfile.STATE_xxx)
     * @param profile profile for the A2DP device
     * @param a2dpVolume New volume for the connecting device. Does nothing if disconnecting.
     * (either {@link android.bluetooth.BluetoothProfile.A2DP} or
     * {@link android.bluetooth.BluetoothProfile.A2DP_SINK})
     * @param suppressNoisyIntent if true the
     * {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent will not be sent.
     * @return a delay in ms that the caller should wait before broadcasting
     * BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED intent.
     * {@hide}
     */
    public int setBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(
                BluetoothDevice device, int state, int profile,
                boolean suppressNoisyIntent, int a2dpVolume) {
        final IAudioService service = getService();
        int delay = 0;
        try {
            delay = service.setBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(device,
                state, profile, suppressNoisyIntent, a2dpVolume);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
        return delay;
    }

     
Indicate A2DP device configuration has changed.

Params:
  • device – Bluetooth device whose configuration has changed.
{@hide}
/**
     * Indicate A2DP device configuration has changed.
     * @param device Bluetooth device whose configuration has changed.
     * {@hide}
     */
    public void handleBluetoothA2dpDeviceConfigChange(BluetoothDevice device) {
        final IAudioService service = getService();
        try {
            service.handleBluetoothA2dpDeviceConfigChange(device);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
{@hide} 
/** {@hide} */
    public IRingtonePlayer getRingtonePlayer() {
        try {
            return getService().getRingtonePlayer();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Used as a key for getProperty to request the native or optimal output sample rate for this device's low latency output stream, in decimal Hz. Latency-sensitive apps should use this value as a default, and offer the user the option to override it. The low latency output stream is typically either the device's primary output stream, or another output stream with smaller buffers. 
/**
     * Used as a key for {@link #getProperty} to request the native or optimal output sample rate
     * for this device's low latency output stream, in decimal Hz.  Latency-sensitive apps
     * should use this value as a default, and offer the user the option to override it.
     * The low latency output stream is typically either the device's primary output stream,
     * or another output stream with smaller buffers.
     */
    // FIXME Deprecate
    public static final String PROPERTY_OUTPUT_SAMPLE_RATE =
            "android.media.property.OUTPUT_SAMPLE_RATE";

    
Used as a key for getProperty to request the native or optimal output buffer size for this device's low latency output stream, in decimal PCM frames. Latency-sensitive apps should use this value as a minimum, and offer the user the option to override it. The low latency output stream is typically either the device's primary output stream, or another output stream with smaller buffers. 
/**
     * Used as a key for {@link #getProperty} to request the native or optimal output buffer size
     * for this device's low latency output stream, in decimal PCM frames.  Latency-sensitive apps
     * should use this value as a minimum, and offer the user the option to override it.
     * The low latency output stream is typically either the device's primary output stream,
     * or another output stream with smaller buffers.
     */
    // FIXME Deprecate
    public static final String PROPERTY_OUTPUT_FRAMES_PER_BUFFER =
            "android.media.property.OUTPUT_FRAMES_PER_BUFFER";

    
Used as a key for getProperty to determine if the default microphone audio source supports near-ultrasound frequencies (range of 18 - 21 kHz). 
/**
     * Used as a key for {@link #getProperty} to determine if the default microphone audio source
     * supports near-ultrasound frequencies (range of 18 - 21 kHz).
     */
    public static final String PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND =
            "android.media.property.SUPPORT_MIC_NEAR_ULTRASOUND";

    
Used as a key for getProperty to determine if the default speaker audio path supports near-ultrasound frequencies (range of 18 - 21 kHz). 
/**
     * Used as a key for {@link #getProperty} to determine if the default speaker audio path
     * supports near-ultrasound frequencies (range of 18 - 21 kHz).
     */
    public static final String PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND =
            "android.media.property.SUPPORT_SPEAKER_NEAR_ULTRASOUND";

    
Used as a key for getProperty to determine if the unprocessed audio source is available and supported with the expected frequency range and level response. 
/**
     * Used as a key for {@link #getProperty} to determine if the unprocessed audio source is
     * available and supported with the expected frequency range and level response.
     */
    public static final String PROPERTY_SUPPORT_AUDIO_SOURCE_UNPROCESSED =
            "android.media.property.SUPPORT_AUDIO_SOURCE_UNPROCESSED";
    
Returns the value of the property with the specified key.

Params:
Returns:A string representing the associated value for that property key,
        or null if there is no value for that key.
/**
     * Returns the value of the property with the specified key.
     * @param key One of the strings corresponding to a property key: either
     *            {@link #PROPERTY_OUTPUT_SAMPLE_RATE},
     *            {@link #PROPERTY_OUTPUT_FRAMES_PER_BUFFER},
     *            {@link #PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND},
     *            {@link #PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND}, or
     *            {@link #PROPERTY_SUPPORT_AUDIO_SOURCE_UNPROCESSED}.
     * @return A string representing the associated value for that property key,
     *         or null if there is no value for that key.
     */
    public String getProperty(String key) {
        if (PROPERTY_OUTPUT_SAMPLE_RATE.equals(key)) {
            int outputSampleRate = AudioSystem.getPrimaryOutputSamplingRate();
            return outputSampleRate > 0 ? Integer.toString(outputSampleRate) : null;
        } else if (PROPERTY_OUTPUT_FRAMES_PER_BUFFER.equals(key)) {
            int outputFramesPerBuffer = AudioSystem.getPrimaryOutputFrameCount();
            return outputFramesPerBuffer > 0 ? Integer.toString(outputFramesPerBuffer) : null;
        } else if (PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND.equals(key)) {
            // Will throw a RuntimeException Resources.NotFoundException if this config value is
            // not found.
            return String.valueOf(getContext().getResources().getBoolean(
                    com.android.internal.R.bool.config_supportMicNearUltrasound));
        } else if (PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND.equals(key)) {
            return String.valueOf(getContext().getResources().getBoolean(
                    com.android.internal.R.bool.config_supportSpeakerNearUltrasound));
        } else if (PROPERTY_SUPPORT_AUDIO_SOURCE_UNPROCESSED.equals(key)) {
            return String.valueOf(getContext().getResources().getBoolean(
                    com.android.internal.R.bool.config_supportAudioSourceUnprocessed));
        } else {
            // null or unknown key
            return null;
        }
    }

    
Returns the estimated latency for the given stream type in milliseconds.
DO NOT UNHIDE. The existing approach for doing A/V sync has too many problems. We need
a better solution.

@hide
/**
     * Returns the estimated latency for the given stream type in milliseconds.
     *
     * DO NOT UNHIDE. The existing approach for doing A/V sync has too many problems. We need
     * a better solution.
     * @hide
     */
    public int getOutputLatency(int streamType) {
        return AudioSystem.getOutputLatency(streamType);
    }

    
Registers a global volume controller interface.  Currently limited to SystemUI.

@hide
/**
     * Registers a global volume controller interface.  Currently limited to SystemUI.
     *
     * @hide
     */
    public void setVolumeController(IVolumeController controller) {
        try {
            getService().setVolumeController(controller);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Notify audio manager about volume controller visibility changes.
Currently limited to SystemUI.

@hide
/**
     * Notify audio manager about volume controller visibility changes.
     * Currently limited to SystemUI.
     *
     * @hide
     */
    public void notifyVolumeControllerVisible(IVolumeController controller, boolean visible) {
        try {
            getService().notifyVolumeControllerVisible(controller, visible);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Only useful for volume controllers.

@hide
/**
     * Only useful for volume controllers.
     * @hide
     */
    public boolean isStreamAffectedByRingerMode(int streamType) {
        try {
            return getService().isStreamAffectedByRingerMode(streamType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Only useful for volume controllers.

@hide
/**
     * Only useful for volume controllers.
     * @hide
     */
    public boolean isStreamAffectedByMute(int streamType) {
        try {
            return getService().isStreamAffectedByMute(streamType);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Only useful for volume controllers.

@hide
/**
     * Only useful for volume controllers.
     * @hide
     */
    public void disableSafeMediaVolume() {
        try {
            getService().disableSafeMediaVolume(mApplicationContext.getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Only useful for volume controllers.

@hide
/**
     * Only useful for volume controllers.
     * @hide
     */
    public void setRingerModeInternal(int ringerMode) {
        try {
            getService().setRingerModeInternal(ringerMode, getContext().getOpPackageName());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Only useful for volume controllers.

@hide
/**
     * Only useful for volume controllers.
     * @hide
     */
    public int getRingerModeInternal() {
        try {
            return getService().getRingerModeInternal();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Only useful for volume controllers.

@hide
/**
     * Only useful for volume controllers.
     * @hide
     */
    public void setVolumePolicy(VolumePolicy policy) {
        try {
            getService().setVolumePolicy(policy);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Set Hdmi Cec system audio mode.

Params:
  • on – whether to be on system audio mode
Returns:output device type. 0 (DEVICE_NONE) if failed to set device.
@hide
/**
     * Set Hdmi Cec system audio mode.
     *
     * @param on whether to be on system audio mode
     * @return output device type. 0 (DEVICE_NONE) if failed to set device.
     * @hide
     */
    public int setHdmiSystemAudioSupported(boolean on) {
        try {
            return getService().setHdmiSystemAudioSupported(on);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
Returns true if Hdmi Cec system audio mode is supported.

@hide
/**
     * Returns true if Hdmi Cec system audio mode is supported.
     *
     * @hide
     */
    @SystemApi
    @SuppressLint("Doclava125") // FIXME is this still used?
    public boolean isHdmiSystemAudioSupported() {
        try {
            return getService().isHdmiSystemAudioSupported();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    /**
     * Return codes for listAudioPorts(), createAudioPatch() ...
     */

    
@hide
CANDIDATE FOR PUBLIC API
/** @hide
     * CANDIDATE FOR PUBLIC API
     */
    public static final int SUCCESS = AudioSystem.SUCCESS;
    
A default error code.

/**
     * A default error code.
     */
    public static final int ERROR = AudioSystem.ERROR;
    
@hide
CANDIDATE FOR PUBLIC API
/** @hide
     * CANDIDATE FOR PUBLIC API
     */
    public static final int ERROR_BAD_VALUE = AudioSystem.BAD_VALUE;
    
@hide
/** @hide
     */
    public static final int ERROR_INVALID_OPERATION = AudioSystem.INVALID_OPERATION;
    
@hide
/** @hide
     */
    public static final int ERROR_PERMISSION_DENIED = AudioSystem.PERMISSION_DENIED;
    
@hide
/** @hide
     */
    public static final int ERROR_NO_INIT = AudioSystem.NO_INIT;
    
An error code indicating that the object reporting it is no longer valid and needs to
be recreated.

/**
     * An error code indicating that the object reporting it is no longer valid and needs to
     * be recreated.
     */
    public static final int ERROR_DEAD_OBJECT = AudioSystem.DEAD_OBJECT;

    
Returns a list of descriptors for all audio ports managed by the audio framework.
Audio ports are nodes in the audio framework or audio hardware that can be configured
or connected and disconnected with createAudioPatch() or releaseAudioPatch().
See AudioPort for a list of attributes of each audio port.

Params:
  • ports – An AudioPort ArrayList where the list will be returned.
@hide
/**
     * Returns a list of descriptors for all audio ports managed by the audio framework.
     * Audio ports are nodes in the audio framework or audio hardware that can be configured
     * or connected and disconnected with createAudioPatch() or releaseAudioPatch().
     * See AudioPort for a list of attributes of each audio port.
     * @param ports An AudioPort ArrayList where the list will be returned.
     * @hide
     */
    public static int listAudioPorts(ArrayList<AudioPort> ports) {
        return updateAudioPortCache(ports, null, null);
    }

    
Returns a list of descriptors for all audio ports managed by the audio framework as
it was before the last update calback.

Params:
  • ports – An AudioPort ArrayList where the list will be returned.
@hide
/**
     * Returns a list of descriptors for all audio ports managed by the audio framework as
     * it was before the last update calback.
     * @param ports An AudioPort ArrayList where the list will be returned.
     * @hide
     */
    public static int listPreviousAudioPorts(ArrayList<AudioPort> ports) {
        return updateAudioPortCache(null, null, ports);
    }

    
Specialized version of listAudioPorts() listing only audio devices (AudioDevicePort)

See Also:
  • listAudioPorts(ArrayList)
@hide
/**
     * Specialized version of listAudioPorts() listing only audio devices (AudioDevicePort)
     * @see listAudioPorts(ArrayList<AudioPort>)
     * @hide
     */
    public static int listAudioDevicePorts(ArrayList<AudioDevicePort> devices) {
        if (devices == null) {
            return ERROR_BAD_VALUE;
        }
        ArrayList<AudioPort> ports = new ArrayList<AudioPort>();
        int status = updateAudioPortCache(ports, null, null);
        if (status == SUCCESS) {
            filterDevicePorts(ports, devices);
        }
        return status;
    }

    
Specialized version of listPreviousAudioPorts() listing only audio devices (AudioDevicePort)

See Also:
  • listPreviousAudioPorts(ArrayList)
@hide
/**
     * Specialized version of listPreviousAudioPorts() listing only audio devices (AudioDevicePort)
     * @see listPreviousAudioPorts(ArrayList<AudioPort>)
     * @hide
     */
    public static int listPreviousAudioDevicePorts(ArrayList<AudioDevicePort> devices) {
        if (devices == null) {
            return ERROR_BAD_VALUE;
        }
        ArrayList<AudioPort> ports = new ArrayList<AudioPort>();
        int status = updateAudioPortCache(null, null, ports);
        if (status == SUCCESS) {
            filterDevicePorts(ports, devices);
        }
        return status;
    }

    private static void filterDevicePorts(ArrayList<AudioPort> ports,
                                          ArrayList<AudioDevicePort> devices) {
        devices.clear();
        for (int i = 0; i < ports.size(); i++) {
            if (ports.get(i) instanceof AudioDevicePort) {
                devices.add((AudioDevicePort)ports.get(i));
            }
        }
    }

    
Create a connection between two or more devices. The framework will reject the request if
device types are not compatible or the implementation does not support the requested
configuration.
NOTE: current implementation is limited to one source and one sink per patch.

Params:
  • patch – AudioPatch array where the newly created patch will be returned.
             As input, if patch[0] is not null, the specified patch will be replaced by the
             new patch created. This avoids calling releaseAudioPatch() when modifying a
             patch and allows the implementation to optimize transitions.
  • sources – List of source audio ports. All must be AudioPort.ROLE_SOURCE.
  • sinks –   List of sink audio ports. All must be AudioPort.ROLE_SINK.
Returns:- SUCCESS if connection is successful. - ERROR_BAD_VALUE if incompatible device types are passed. - ERROR_INVALID_OPERATION if the requested connection is not supported. - ERROR_PERMISSION_DENIED if the client does not have permission to create a patch. - ERROR_DEAD_OBJECT if the server process is dead - ERROR if patch cannot be connected for any other reason. patch[0] contains the newly created patch
@hide
/**
     * Create a connection between two or more devices. The framework will reject the request if
     * device types are not compatible or the implementation does not support the requested
     * configuration.
     * NOTE: current implementation is limited to one source and one sink per patch.
     * @param patch AudioPatch array where the newly created patch will be returned.
     *              As input, if patch[0] is not null, the specified patch will be replaced by the
     *              new patch created. This avoids calling releaseAudioPatch() when modifying a
     *              patch and allows the implementation to optimize transitions.
     * @param sources List of source audio ports. All must be AudioPort.ROLE_SOURCE.
     * @param sinks   List of sink audio ports. All must be AudioPort.ROLE_SINK.
     *
     * @return - {@link #SUCCESS} if connection is successful.
     *         - {@link #ERROR_BAD_VALUE} if incompatible device types are passed.
     *         - {@link #ERROR_INVALID_OPERATION} if the requested connection is not supported.
     *         - {@link #ERROR_PERMISSION_DENIED} if the client does not have permission to create
     *         a patch.
     *         - {@link #ERROR_DEAD_OBJECT} if the server process is dead
     *         - {@link #ERROR} if patch cannot be connected for any other reason.
     *
     *         patch[0] contains the newly created patch
     * @hide
     */
    public static int createAudioPatch(AudioPatch[] patch,
                                 AudioPortConfig[] sources,
                                 AudioPortConfig[] sinks) {
        return AudioSystem.createAudioPatch(patch, sources, sinks);
    }

    
Releases an existing audio patch connection.

Params:
  • patch – The audio patch to disconnect.
Returns:- SUCCESS if disconnection is successful. - ERROR_BAD_VALUE if the specified patch does not exist. - ERROR_PERMISSION_DENIED if the client does not have permission to release a patch. - ERROR_DEAD_OBJECT if the server process is dead - ERROR if patch cannot be released for any other reason.
@hide
/**
     * Releases an existing audio patch connection.
     * @param patch The audio patch to disconnect.
     * @return - {@link #SUCCESS} if disconnection is successful.
     *         - {@link #ERROR_BAD_VALUE} if the specified patch does not exist.
     *         - {@link #ERROR_PERMISSION_DENIED} if the client does not have permission to release
     *         a patch.
     *         - {@link #ERROR_DEAD_OBJECT} if the server process is dead
     *         - {@link #ERROR} if patch cannot be released for any other reason.
     * @hide
     */
    public static int releaseAudioPatch(AudioPatch patch) {
        return AudioSystem.releaseAudioPatch(patch);
    }

    
List all existing connections between audio ports.

Params:
  • patches – An AudioPatch array where the list will be returned.
@hide
/**
     * List all existing connections between audio ports.
     * @param patches An AudioPatch array where the list will be returned.
     * @hide
     */
    public static int listAudioPatches(ArrayList<AudioPatch> patches) {
        return updateAudioPortCache(null, patches, null);
    }

    
Set the gain on the specified AudioPort. The AudioGainConfig config is build by
AudioGain.buildConfig()

@hide
/**
     * Set the gain on the specified AudioPort. The AudioGainConfig config is build by
     * AudioGain.buildConfig()
     * @hide
     */
    public static int setAudioPortGain(AudioPort port, AudioGainConfig gain) {
        if (port == null || gain == null) {
            return ERROR_BAD_VALUE;
        }
        AudioPortConfig activeConfig = port.activeConfig();
        AudioPortConfig config = new AudioPortConfig(port, activeConfig.samplingRate(),
                                        activeConfig.channelMask(), activeConfig.format(), gain);
        config.mConfigMask = AudioPortConfig.GAIN;
        return AudioSystem.setAudioPortConfig(config);
    }

    
Listener registered by client to be notified upon new audio port connections,
disconnections or attributes update.

@hide
/**
     * Listener registered by client to be notified upon new audio port connections,
     * disconnections or attributes update.
     * @hide
     */
    public interface OnAudioPortUpdateListener {
        
Callback method called upon audio port list update.

Params:
  • portList – the updated list of audio ports
/**
         * Callback method called upon audio port list update.
         * @param portList the updated list of audio ports
         */
        public void onAudioPortListUpdate(AudioPort[] portList);

        
Callback method called upon audio patch list update.

Params:
  • patchList – the updated list of audio patches
/**
         * Callback method called upon audio patch list update.
         * @param patchList the updated list of audio patches
         */
        public void onAudioPatchListUpdate(AudioPatch[] patchList);

        
Callback method called when the mediaserver dies

/**
         * Callback method called when the mediaserver dies
         */
        public void onServiceDied();
    }

    
Register an audio port list update listener.

@hide
/**
     * Register an audio port list update listener.
     * @hide
     */
    public void registerAudioPortUpdateListener(OnAudioPortUpdateListener l) {
        sAudioPortEventHandler.init();
        sAudioPortEventHandler.registerListener(l);
    }

    
Unregister an audio port list update listener.

@hide
/**
     * Unregister an audio port list update listener.
     * @hide
     */
    public void unregisterAudioPortUpdateListener(OnAudioPortUpdateListener l) {
        sAudioPortEventHandler.unregisterListener(l);
    }

    //
    // AudioPort implementation
    //

    static final int AUDIOPORT_GENERATION_INIT = 0;
    static Integer sAudioPortGeneration = new Integer(AUDIOPORT_GENERATION_INIT);
    static ArrayList<AudioPort> sAudioPortsCached = new ArrayList<AudioPort>();
    static ArrayList<AudioPort> sPreviousAudioPortsCached = new ArrayList<AudioPort>();
    static ArrayList<AudioPatch> sAudioPatchesCached = new ArrayList<AudioPatch>();

    static int resetAudioPortGeneration() {
        int generation;
        synchronized (sAudioPortGeneration) {
            generation = sAudioPortGeneration;
            sAudioPortGeneration = AUDIOPORT_GENERATION_INIT;
        }
        return generation;
    }

    static int updateAudioPortCache(ArrayList<AudioPort> ports, ArrayList<AudioPatch> patches,
                                    ArrayList<AudioPort> previousPorts) {
        sAudioPortEventHandler.init();
        synchronized (sAudioPortGeneration) {

            if (sAudioPortGeneration == AUDIOPORT_GENERATION_INIT) {
                int[] patchGeneration = new int[1];
                int[] portGeneration = new int[1];
                int status;
                ArrayList<AudioPort> newPorts = new ArrayList<AudioPort>();
                ArrayList<AudioPatch> newPatches = new ArrayList<AudioPatch>();

                do {
                    newPorts.clear();
                    status = AudioSystem.listAudioPorts(newPorts, portGeneration);
                    if (status != SUCCESS) {
                        Log.w(TAG, "updateAudioPortCache: listAudioPorts failed");
                        return status;
                    }
                    newPatches.clear();
                    status = AudioSystem.listAudioPatches(newPatches, patchGeneration);
                    if (status != SUCCESS) {
                        Log.w(TAG, "updateAudioPortCache: listAudioPatches failed");
                        return status;
                    }
                    // Loop until patch generation is the same as port generation unless audio ports
                    // and audio patches are not null.
                } while (patchGeneration[0] != portGeneration[0]
                        && (ports == null || patches == null));
                // If the patch generation doesn't equal port generation, return ERROR here in case
                // of mismatch between audio ports and audio patches.
                if (patchGeneration[0] != portGeneration[0]) {
                    return ERROR;
                }

                for (int i = 0; i < newPatches.size(); i++) {
                    for (int j = 0; j < newPatches.get(i).sources().length; j++) {
                        AudioPortConfig portCfg = updatePortConfig(newPatches.get(i).sources()[j],
                                                                   newPorts);
                        newPatches.get(i).sources()[j] = portCfg;
                    }
                    for (int j = 0; j < newPatches.get(i).sinks().length; j++) {
                        AudioPortConfig portCfg = updatePortConfig(newPatches.get(i).sinks()[j],
                                                                   newPorts);
                        newPatches.get(i).sinks()[j] = portCfg;
                    }
                }
                for (Iterator<AudioPatch> i = newPatches.iterator(); i.hasNext(); ) {
                    AudioPatch newPatch = i.next();
                    boolean hasInvalidPort = false;
                    for (AudioPortConfig portCfg : newPatch.sources()) {
                        if (portCfg == null) {
                            hasInvalidPort = true;
                            break;
                        }
                    }
                    for (AudioPortConfig portCfg : newPatch.sinks()) {
                        if (portCfg == null) {
                            hasInvalidPort = true;
                            break;
                        }
                    }
                    if (hasInvalidPort) {
                        // Temporarily remove patches with invalid ports. One who created the patch
                        // is responsible for dealing with the port change.
                        i.remove();
                    }
                }

                sPreviousAudioPortsCached = sAudioPortsCached;
                sAudioPortsCached = newPorts;
                sAudioPatchesCached = newPatches;
                sAudioPortGeneration = portGeneration[0];
            }
            if (ports != null) {
                ports.clear();
                ports.addAll(sAudioPortsCached);
            }
            if (patches != null) {
                patches.clear();
                patches.addAll(sAudioPatchesCached);
            }
            if (previousPorts != null) {
                previousPorts.clear();
                previousPorts.addAll(sPreviousAudioPortsCached);
            }
        }
        return SUCCESS;
    }

    static AudioPortConfig updatePortConfig(AudioPortConfig portCfg, ArrayList<AudioPort> ports) {
        AudioPort port = portCfg.port();
        int k;
        for (k = 0; k < ports.size(); k++) {
            // compare handles because the port returned by JNI is not of the correct
            // subclass
            if (ports.get(k).handle().equals(port.handle())) {
                port = ports.get(k);
                break;
            }
        }
        if (k == ports.size()) {
            // this hould never happen
            Log.e(TAG, "updatePortConfig port not found for handle: "+port.handle().id());
            return null;
        }
        AudioGainConfig gainCfg = portCfg.gain();
        if (gainCfg != null) {
            AudioGain gain = port.gain(gainCfg.index());
            gainCfg = gain.buildConfig(gainCfg.mode(),
                                       gainCfg.channelMask(),
                                       gainCfg.values(),
                                       gainCfg.rampDurationMs());
        }
        return port.buildConfig(portCfg.samplingRate(),
                                                 portCfg.channelMask(),
                                                 portCfg.format(),
                                                 gainCfg);
    }

    private OnAmPortUpdateListener mPortListener = null;

    
The message sent to apps when the contents of the device list changes if they provide a Handler object to addOnAudioDeviceConnectionListener(). 
/**
     * The message sent to apps when the contents of the device list changes if they provide
     * a {@link Handler} object to addOnAudioDeviceConnectionListener().
     */
    private final static int MSG_DEVICES_CALLBACK_REGISTERED = 0;
    private final static int MSG_DEVICES_DEVICES_ADDED = 1;
    private final static int MSG_DEVICES_DEVICES_REMOVED = 2;

    
The list of AudioDeviceCallback objects to receive add/remove notifications. 
/**
     * The list of {@link AudioDeviceCallback} objects to receive add/remove notifications.
     */
    private final ArrayMap<AudioDeviceCallback, NativeEventHandlerDelegate> mDeviceCallbacks =
            new ArrayMap<AudioDeviceCallback, NativeEventHandlerDelegate>();

    /**
     * The following are flags to allow users of {@link AudioManager#getDevices(int)} to filter
     * the results list to only those device types they are interested in.
     */
    
Specifies to the getDevices(int) method to include source (i.e. input) audio devices. 
/**
     * Specifies to the {@link AudioManager#getDevices(int)} method to include
     * source (i.e. input) audio devices.
     */
    public static final int GET_DEVICES_INPUTS    = 0x0001;

    
Specifies to the getDevices(int) method to include sink (i.e. output) audio devices. 
/**
     * Specifies to the {@link AudioManager#getDevices(int)} method to include
     * sink (i.e. output) audio devices.
     */
    public static final int GET_DEVICES_OUTPUTS   = 0x0002;

    
Specifies to the getDevices(int) method to include both source and sink devices. 
/**
     * Specifies to the {@link AudioManager#getDevices(int)} method to include both
     * source and sink devices.
     */
    public static final int GET_DEVICES_ALL = GET_DEVICES_OUTPUTS | GET_DEVICES_INPUTS;

    
Determines if a given AudioDevicePort meets the specified filter criteria.

Params:
  • port –  The port to test.
  • flags – A set of bitflags specifying the criteria to test.
See Also:
  • GET_DEVICES_OUTPUTS and GET_DEVICES_INPUTS
/**
     * Determines if a given AudioDevicePort meets the specified filter criteria.
     * @param port  The port to test.
     * @param flags A set of bitflags specifying the criteria to test.
     * @see {@link GET_DEVICES_OUTPUTS} and {@link GET_DEVICES_INPUTS}
     **/
    private static boolean checkFlags(AudioDevicePort port, int flags) {
        return port.role() == AudioPort.ROLE_SINK && (flags & GET_DEVICES_OUTPUTS) != 0 ||
               port.role() == AudioPort.ROLE_SOURCE && (flags & GET_DEVICES_INPUTS) != 0;
    }

    private static boolean checkTypes(AudioDevicePort port) {
        return AudioDeviceInfo.convertInternalDeviceToDeviceType(port.type()) !=
                    AudioDeviceInfo.TYPE_UNKNOWN;
    }

    
Returns an array of AudioDeviceInfo objects corresponding to the audio devices currently connected to the system and meeting the criteria specified in the flags parameter.

Params:
  • flags – A set of bitflags specifying the criteria to test.
See Also:
Returns:A (possibly zero-length) array of AudioDeviceInfo objects.
/**
     * Returns an array of {@link AudioDeviceInfo} objects corresponding to the audio devices
     * currently connected to the system and meeting the criteria specified in the
     * <code>flags</code> parameter.
     * @param flags A set of bitflags specifying the criteria to test.
     * @see #GET_DEVICES_OUTPUTS
     * @see #GET_DEVICES_INPUTS
     * @see #GET_DEVICES_ALL
     * @return A (possibly zero-length) array of AudioDeviceInfo objects.
     */
    public AudioDeviceInfo[] getDevices(int flags) {
        return getDevicesStatic(flags);
    }

    
Does the actual computation to generate an array of (externally-visible) AudioDeviceInfo
objects from the current (internal) AudioDevicePort list.

/**
     * Does the actual computation to generate an array of (externally-visible) AudioDeviceInfo
     * objects from the current (internal) AudioDevicePort list.
     */
    private static AudioDeviceInfo[]
        infoListFromPortList(ArrayList<AudioDevicePort> ports, int flags) {

        // figure out how many AudioDeviceInfo we need space for...
        int numRecs = 0;
        for (AudioDevicePort port : ports) {
            if (checkTypes(port) && checkFlags(port, flags)) {
                numRecs++;
            }
        }

        // Now load them up...
        AudioDeviceInfo[] deviceList = new AudioDeviceInfo[numRecs];
        int slot = 0;
        for (AudioDevicePort port : ports) {
            if (checkTypes(port) && checkFlags(port, flags)) {
                deviceList[slot++] = new AudioDeviceInfo(port);
            }
        }

        return deviceList;
    }

    /*
     * Calculate the list of ports that are in ports_B, but not in ports_A. This is used by
     * the add/remove callback mechanism to provide a list of the newly added or removed devices
     * rather than the whole list and make the app figure it out.
     * Note that calling this method with:
     *  ports_A == PREVIOUS_ports and ports_B == CURRENT_ports will calculated ADDED ports.
     *  ports_A == CURRENT_ports and ports_B == PREVIOUS_ports will calculated REMOVED ports.
     */
    private static AudioDeviceInfo[] calcListDeltas(
            ArrayList<AudioDevicePort> ports_A, ArrayList<AudioDevicePort> ports_B, int flags) {

        ArrayList<AudioDevicePort> delta_ports = new ArrayList<AudioDevicePort>();

        AudioDevicePort cur_port = null;
        for (int cur_index = 0; cur_index < ports_B.size(); cur_index++) {
            boolean cur_port_found = false;
            cur_port = ports_B.get(cur_index);
            for (int prev_index = 0;
                 prev_index < ports_A.size() && !cur_port_found;
                 prev_index++) {
                cur_port_found = (cur_port.id() == ports_A.get(prev_index).id());
            }

            if (!cur_port_found) {
                delta_ports.add(cur_port);
            }
        }

        return infoListFromPortList(delta_ports, flags);
    }

    
Generates a list of AudioDeviceInfo objects corresponding to the audio devices currently
connected to the system and meeting the criteria specified in the flags
parameter.
This is an internal function. The public API front is getDevices(int).

Params:
  • flags – A set of bitflags specifying the criteria to test.
See Also:
Returns:A (possibly zero-length) array of AudioDeviceInfo objects.
@hide
/**
     * Generates a list of AudioDeviceInfo objects corresponding to the audio devices currently
     * connected to the system and meeting the criteria specified in the <code>flags</code>
     * parameter.
     * This is an internal function. The public API front is getDevices(int).
     * @param flags A set of bitflags specifying the criteria to test.
     * @see #GET_DEVICES_OUTPUTS
     * @see #GET_DEVICES_INPUTS
     * @see #GET_DEVICES_ALL
     * @return A (possibly zero-length) array of AudioDeviceInfo objects.
     * @hide
     */
    public static AudioDeviceInfo[] getDevicesStatic(int flags) {
        ArrayList<AudioDevicePort> ports = new ArrayList<AudioDevicePort>();
        int status = AudioManager.listAudioDevicePorts(ports);
        if (status != AudioManager.SUCCESS) {
            // fail and bail!
            return new AudioDeviceInfo[0];  // Always return an array.
        }

        return infoListFromPortList(ports, flags);
    }

    
Registers an AudioDeviceCallback object to receive notifications of changes to the set of connected audio devices. 
Params:
  • callback – The AudioDeviceCallback object to receive connect/disconnect notifications.
  • handler – Specifies the Handler object for the thread on which to execute the callback. If null, the Handler associated with the main Looper will be used.
/**
     * Registers an {@link AudioDeviceCallback} object to receive notifications of changes
     * to the set of connected audio devices.
     * @param callback The {@link AudioDeviceCallback} object to receive connect/disconnect
     * notifications.
     * @param handler Specifies the {@link Handler} object for the thread on which to execute
     * the callback. If <code>null</code>, the {@link Handler} associated with the main
     * {@link Looper} will be used.
     */
    public void registerAudioDeviceCallback(AudioDeviceCallback callback,
            android.os.Handler handler) {
        synchronized (mDeviceCallbacks) {
            if (callback != null && !mDeviceCallbacks.containsKey(callback)) {
                if (mDeviceCallbacks.size() == 0) {
                    if (mPortListener == null) {
                        mPortListener = new OnAmPortUpdateListener();
                    }
                    registerAudioPortUpdateListener(mPortListener);
                }
                NativeEventHandlerDelegate delegate =
                        new NativeEventHandlerDelegate(callback, handler);
                mDeviceCallbacks.put(callback, delegate);
                broadcastDeviceListChange_sync(delegate.getHandler());
            }
        }
    }

    
Unregisters an AudioDeviceCallback object which has been previously registered to receive notifications of changes to the set of connected audio devices. 
Params:
/**
     * Unregisters an {@link AudioDeviceCallback} object which has been previously registered
     * to receive notifications of changes to the set of connected audio devices.
     * @param callback The {@link AudioDeviceCallback} object that was previously registered
     * with {@link AudioManager#registerAudioDeviceCallback} to be unregistered.
     */
    public void unregisterAudioDeviceCallback(AudioDeviceCallback callback) {
        synchronized (mDeviceCallbacks) {
            if (mDeviceCallbacks.containsKey(callback)) {
                mDeviceCallbacks.remove(callback);
                if (mDeviceCallbacks.size() == 0) {
                    unregisterAudioPortUpdateListener(mPortListener);
                }
            }
        }
    }

    
Set port id for microphones by matching device type and address.

@hide
/**
     * Set port id for microphones by matching device type and address.
     * @hide
     */
    public static void setPortIdForMicrophones(ArrayList<MicrophoneInfo> microphones) {
        AudioDeviceInfo[] devices = getDevicesStatic(AudioManager.GET_DEVICES_INPUTS);
        for (int i = microphones.size() - 1; i >= 0; i--) {
            boolean foundPortId = false;
            for (AudioDeviceInfo device : devices) {
                if (device.getPort().type() == microphones.get(i).getInternalDeviceType()
                        && TextUtils.equals(device.getAddress(), microphones.get(i).getAddress())) {
                    microphones.get(i).setId(device.getId());
                    foundPortId = true;
                    break;
                }
            }
            if (!foundPortId) {
                Log.i(TAG, "Failed to find port id for device with type:"
                        + microphones.get(i).getType() + " address:"
                        + microphones.get(i).getAddress());
                microphones.remove(i);
            }
        }
    }

    
@hide
/**
     * Convert {@link AudioDeviceInfo} to {@link MicrophoneInfo}.
     * @hide
     */
    public static MicrophoneInfo microphoneInfoFromAudioDeviceInfo(AudioDeviceInfo deviceInfo) {
        int deviceType = deviceInfo.getType();
        int micLocation = (deviceType == AudioDeviceInfo.TYPE_BUILTIN_MIC
                || deviceType == AudioDeviceInfo.TYPE_TELEPHONY) ? MicrophoneInfo.LOCATION_MAINBODY
                : deviceType == AudioDeviceInfo.TYPE_UNKNOWN ? MicrophoneInfo.LOCATION_UNKNOWN
                        : MicrophoneInfo.LOCATION_PERIPHERAL;
        MicrophoneInfo microphone = new MicrophoneInfo(
                deviceInfo.getPort().name() + deviceInfo.getId(),
                deviceInfo.getPort().type(), deviceInfo.getAddress(), micLocation,
                MicrophoneInfo.GROUP_UNKNOWN, MicrophoneInfo.INDEX_IN_THE_GROUP_UNKNOWN,
                MicrophoneInfo.POSITION_UNKNOWN, MicrophoneInfo.ORIENTATION_UNKNOWN,
                new ArrayList<Pair<Float, Float>>(), new ArrayList<Pair<Integer, Integer>>(),
                MicrophoneInfo.SENSITIVITY_UNKNOWN, MicrophoneInfo.SPL_UNKNOWN,
                MicrophoneInfo.SPL_UNKNOWN, MicrophoneInfo.DIRECTIONALITY_UNKNOWN);
        microphone.setId(deviceInfo.getId());
        return microphone;
    }

    
Add MicrophoneInfo by device information while filtering certain types. 
/**
     * Add {@link MicrophoneInfo} by device information while filtering certain types.
     */
    private void addMicrophonesFromAudioDeviceInfo(ArrayList<MicrophoneInfo> microphones,
                    HashSet<Integer> filterTypes) {
        AudioDeviceInfo[] devices = getDevicesStatic(GET_DEVICES_INPUTS);
        for (AudioDeviceInfo device : devices) {
            if (filterTypes.contains(device.getType())) {
                continue;
            }
            MicrophoneInfo microphone = microphoneInfoFromAudioDeviceInfo(device);
            microphones.add(microphone);
        }
    }

    
Returns a list of MicrophoneInfo that corresponds to the characteristics of all available microphones. The list is empty when no microphones are available on the device. An error during the query will result in an IOException being thrown. 
Throws:
Returns:a list that contains all microphones' characteristics
/**
     * Returns a list of {@link MicrophoneInfo} that corresponds to the characteristics
     * of all available microphones. The list is empty when no microphones are available
     * on the device. An error during the query will result in an IOException being thrown.
     *
     * @return a list that contains all microphones' characteristics
     * @throws IOException if an error occurs.
     */
    public List<MicrophoneInfo> getMicrophones() throws IOException {
        ArrayList<MicrophoneInfo> microphones = new ArrayList<MicrophoneInfo>();
        int status = AudioSystem.getMicrophones(microphones);
        HashSet<Integer> filterTypes = new HashSet<>();
        filterTypes.add(AudioDeviceInfo.TYPE_TELEPHONY);
        if (status != AudioManager.SUCCESS) {
            // fail and populate microphones with unknown characteristics by device information.
            if (status != AudioManager.ERROR_INVALID_OPERATION) {
                Log.e(TAG, "getMicrophones failed:" + status);
            }
            Log.i(TAG, "fallback on device info");
            addMicrophonesFromAudioDeviceInfo(microphones, filterTypes);
            return microphones;
        }
        setPortIdForMicrophones(microphones);
        filterTypes.add(AudioDeviceInfo.TYPE_BUILTIN_MIC);
        addMicrophonesFromAudioDeviceInfo(microphones, filterTypes);
        return microphones;
    }

    // Since we need to calculate the changes since THE LAST NOTIFICATION, and not since the
    // (unpredictable) last time updateAudioPortCache() was called by someone, keep a list
    // of the ports that exist at the time of the last notification.
    private ArrayList<AudioDevicePort> mPreviousPorts = new ArrayList<AudioDevicePort>();

    
Internal method to compute and generate add/remove messages and then send to any
registered callbacks. Must be called synchronized on mDeviceCallbacks.

/**
     * Internal method to compute and generate add/remove messages and then send to any
     * registered callbacks. Must be called synchronized on mDeviceCallbacks.
     */
    private void broadcastDeviceListChange_sync(Handler handler) {
        int status;

        // Get the new current set of ports
        ArrayList<AudioDevicePort> current_ports = new ArrayList<AudioDevicePort>();
        status = AudioManager.listAudioDevicePorts(current_ports);
        if (status != AudioManager.SUCCESS) {
            return;
        }

        if (handler != null) {
            // This is the callback for the registration, so send the current list
            AudioDeviceInfo[] deviceList =
                    infoListFromPortList(current_ports, GET_DEVICES_ALL);
            handler.sendMessage(
                    Message.obtain(handler, MSG_DEVICES_CALLBACK_REGISTERED, deviceList));
        } else {
            AudioDeviceInfo[] added_devices =
                    calcListDeltas(mPreviousPorts, current_ports, GET_DEVICES_ALL);
            AudioDeviceInfo[] removed_devices =
                    calcListDeltas(current_ports, mPreviousPorts, GET_DEVICES_ALL);
            if (added_devices.length != 0 || removed_devices.length != 0) {
                for (int i = 0; i < mDeviceCallbacks.size(); i++) {
                    handler = mDeviceCallbacks.valueAt(i).getHandler();
                    if (handler != null) {
                        if (removed_devices.length != 0) {
                            handler.sendMessage(Message.obtain(handler,
                                    MSG_DEVICES_DEVICES_REMOVED,
                                    removed_devices));
                        }
                        if (added_devices.length != 0) {
                            handler.sendMessage(Message.obtain(handler,
                                    MSG_DEVICES_DEVICES_ADDED,
                                    added_devices));
                        }
                    }
                }
            }
        }

        mPreviousPorts = current_ports;
    }

    
Handles Port list update notifications from the AudioManager

/**
     * Handles Port list update notifications from the AudioManager
     */
    private class OnAmPortUpdateListener implements AudioManager.OnAudioPortUpdateListener {
        static final String TAG = "OnAmPortUpdateListener";
        public void onAudioPortListUpdate(AudioPort[] portList) {
            synchronized (mDeviceCallbacks) {
                broadcastDeviceListChange_sync(null);
            }
        }

        
Callback method called upon audio patch list update.
Note: We don't do anything with Patches at this time, so ignore this notification.

Params:
  • patchList – the updated list of audio patches.
/**
         * Callback method called upon audio patch list update.
         * Note: We don't do anything with Patches at this time, so ignore this notification.
         * @param patchList the updated list of audio patches.
         */
        public void onAudioPatchListUpdate(AudioPatch[] patchList) {}

        
Callback method called when the mediaserver dies

/**
         * Callback method called when the mediaserver dies
         */
        public void onServiceDied() {
            synchronized (mDeviceCallbacks) {
                broadcastDeviceListChange_sync(null);
            }
        }
    }


    
@hide
Abstract class to receive event notification about audioserver process state.
/**
     * @hide
     * Abstract class to receive event notification about audioserver process state.
     */
    @SystemApi
    public abstract static class AudioServerStateCallback {
        public void onAudioServerDown() { }
        public void onAudioServerUp() { }
    }

    private Executor mAudioServerStateExec;
    private AudioServerStateCallback mAudioServerStateCb;
    private final Object mAudioServerStateCbLock = new Object();

    private final IAudioServerStateDispatcher mAudioServerStateDispatcher =
            new IAudioServerStateDispatcher.Stub() {
        @Override
        public void dispatchAudioServerStateChange(boolean state) {
            Executor exec;
            AudioServerStateCallback cb;

            synchronized (mAudioServerStateCbLock) {
                exec = mAudioServerStateExec;
                cb = mAudioServerStateCb;
            }

            if ((exec == null) || (cb == null)) {
                return;
            }
            if (state) {
                exec.execute(() -> cb.onAudioServerUp());
            } else {
                exec.execute(() -> cb.onAudioServerDown());
            }
        }
    };

    
Params:
  • executor – Executor to handle the callbacks
  • stateCallback – the callback to receive the audio server state changes
       To remove the callabck, pass a null reference for both executor and stateCallback.
@hide
Registers a callback for notification of audio server state changes.
/**
     * @hide
     * Registers a callback for notification of audio server state changes.
     * @param executor {@link Executor} to handle the callbacks
     * @param stateCallback the callback to receive the audio server state changes
     *        To remove the callabck, pass a null reference for both executor and stateCallback.
     */
    @SystemApi
    public void setAudioServerStateCallback(@NonNull Executor executor,
            @NonNull AudioServerStateCallback stateCallback) {
        if (stateCallback == null) {
            throw new IllegalArgumentException("Illegal null AudioServerStateCallback");
        }
        if (executor == null) {
            throw new IllegalArgumentException(
                    "Illegal null Executor for the AudioServerStateCallback");
        }

        synchronized (mAudioServerStateCbLock) {
            if (mAudioServerStateCb != null) {
                throw new IllegalStateException(
                    "setAudioServerStateCallback called with already registered callabck");
            }
            final IAudioService service = getService();
            try {
                service.registerAudioServerStateDispatcher(mAudioServerStateDispatcher);
            } catch (RemoteException e) {
                throw e.rethrowFromSystemServer();
            }
            mAudioServerStateExec = executor;
            mAudioServerStateCb = stateCallback;
        }
    }

    
@hide
Unregisters the callback for notification of audio server state changes.
/**
     * @hide
     * Unregisters the callback for notification of audio server state changes.
     */
    @SystemApi
    public void clearAudioServerStateCallback() {
        synchronized (mAudioServerStateCbLock) {
            if (mAudioServerStateCb != null) {
                final IAudioService service = getService();
                try {
                    service.unregisterAudioServerStateDispatcher(
                            mAudioServerStateDispatcher);
                } catch (RemoteException e) {
                    throw e.rethrowFromSystemServer();
                }
            }
            mAudioServerStateExec = null;
            mAudioServerStateCb = null;
        }
    }

    
@hide
Checks if native audioservice is running or not.
Returns:true if native audioservice runs, false otherwise.
/**
     * @hide
     * Checks if native audioservice is running or not.
     * @return true if native audioservice runs, false otherwise.
     */
    @SystemApi
    public boolean isAudioServerRunning() {
        final IAudioService service = getService();
        try {
            return service.isAudioServerRunning();
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    
@hide
Returns all surround formats.
Returns:a map where the key is a surround format and
the value indicates the surround format is enabled or not
/**
     * @hide
     * Returns all surround formats.
     * @return a map where the key is a surround format and
     * the value indicates the surround format is enabled or not
     */
    public Map<Integer, Boolean> getSurroundFormats() {
        Map<Integer, Boolean> surroundFormats = new HashMap<>();
        int status = AudioSystem.getSurroundFormats(surroundFormats, false);
        if (status != AudioManager.SUCCESS) {
            // fail and bail!
            Log.e(TAG, "getSurroundFormats failed:" + status);
            return new HashMap<Integer, Boolean>(); // Always return a map.
        }
        return surroundFormats;
    }

    
Params:
@hide
Set a certain surround format as enabled or not.
Returns:true if successful, otherwise false
/**
     * @hide
     * Set a certain surround format as enabled or not.
     * @param audioFormat a surround format, the value is one of
     *        {@link AudioFormat#ENCODING_AC3}, {@link AudioFormat#ENCODING_E_AC3},
     *        {@link AudioFormat#ENCODING_DTS}, {@link AudioFormat#ENCODING_DTS_HD},
     *        {@link AudioFormat#ENCODING_AAC_LC}, {@link AudioFormat#ENCODING_DOLBY_TRUEHD},
     *        {@link AudioFormat#ENCODING_E_AC3_JOC}. Once {@link AudioFormat#ENCODING_AAC_LC} is
     *        set as enabled, {@link AudioFormat#ENCODING_AAC_LC},
     *        {@link AudioFormat#ENCODING_AAC_HE_V1}, {@link AudioFormat#ENCODING_AAC_HE_V2},
     *        {@link AudioFormat#ENCODING_AAC_ELD}, {@link AudioFormat#ENCODING_AAC_XHE} are
     *        all enabled.
     * @param enabled the required surround format state, true for enabled, false for disabled
     * @return true if successful, otherwise false
     */
    public boolean setSurroundFormatEnabled(
            @AudioFormat.SurroundSoundEncoding int audioFormat, boolean enabled) {
        int status = AudioSystem.setSurroundFormatEnabled(audioFormat, enabled);
        return status == AudioManager.SUCCESS;
    }

    
@hide
Returns all surround formats that are reported by the connected HDMI device.
The keys are not affected by calling setSurroundFormatEnabled(), and the values
are not affected by calling setSurroundFormatEnabled() when in AUTO mode.
This information can used to show the AUTO setting for SurroundSound.
Returns:a map where the key is a surround format and
the value indicates the surround format is enabled or not
/**
     * @hide
     * Returns all surround formats that are reported by the connected HDMI device.
     * The keys are not affected by calling setSurroundFormatEnabled(), and the values
     * are not affected by calling setSurroundFormatEnabled() when in AUTO mode.
     * This information can used to show the AUTO setting for SurroundSound.
     *
     * @return a map where the key is a surround format and
     * the value indicates the surround format is enabled or not
     */
    public Map<Integer, Boolean> getReportedSurroundFormats() {
        Map<Integer, Boolean> reportedSurroundFormats = new HashMap<>();
        int status = AudioSystem.getSurroundFormats(reportedSurroundFormats, true);
        if (status != AudioManager.SUCCESS) {
            // fail and bail!
            Log.e(TAG, "getReportedSurroundFormats failed:" + status);
            return new HashMap<Integer, Boolean>(); // Always return a map.
        }
        return reportedSurroundFormats;
    }


    //---------------------------------------------------------
    // Inner classes
    //--------------------
    
Helper class to handle the forwarding of native events to the appropriate listener
(potentially) handled in a different thread.

/**
     * Helper class to handle the forwarding of native events to the appropriate listener
     * (potentially) handled in a different thread.
     */
    private class NativeEventHandlerDelegate {
        private final Handler mHandler;

        NativeEventHandlerDelegate(final AudioDeviceCallback callback,
                                   Handler handler) {
            // find the looper for our new event handler
            Looper looper;
            if (handler != null) {
                looper = handler.getLooper();
            } else {
                // no given handler, use the looper the addListener call was called in
                looper = Looper.getMainLooper();
            }

            // construct the event handler with this looper
            if (looper != null) {
                // implement the event handler delegate
                mHandler = new Handler(looper) {
                    @Override
                    public void handleMessage(Message msg) {
                        switch(msg.what) {
                        case MSG_DEVICES_CALLBACK_REGISTERED:
                        case MSG_DEVICES_DEVICES_ADDED:
                            if (callback != null) {
                                callback.onAudioDevicesAdded((AudioDeviceInfo[])msg.obj);
                            }
                            break;

                        case MSG_DEVICES_DEVICES_REMOVED:
                            if (callback != null) {
                                callback.onAudioDevicesRemoved((AudioDeviceInfo[])msg.obj);
                            }
                           break;

                        default:
                            Log.e(TAG, "Unknown native event type: " + msg.what);
                            break;
                        }
                    }
                };
            } else {
                mHandler = null;
            }
        }

        Handler getHandler() {
            return mHandler;
        }
    }
}