https://source.android.com/ 
/*
 * Copyright (C) 2010 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.nfc;

import android.annotation.RequiresPermission;
import android.annotation.SdkConstant;
import android.annotation.SdkConstant.SdkConstantType;
import android.annotation.SystemApi;
import android.app.Activity;
import android.app.ActivityThread;
import android.app.OnActivityPausedListener;
import android.app.PendingIntent;
import android.content.Context;
import android.content.IntentFilter;
import android.content.pm.IPackageManager;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.Ndef;
import android.nfc.tech.NfcA;
import android.nfc.tech.NfcF;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.util.Log;

import java.io.IOException;
import java.util.HashMap;


Represents the local NFC adapter.

 Use the helper getDefaultAdapter(Context) to get the default NFC adapter for this Android device. 


Developer Guides


For more information about using NFC, read the
Near Field Communication developer guide.


To perform basic file sharing between devices, read
Sharing Files with NFC.



/**
 * Represents the local NFC adapter.
 * <p>
 * Use the helper {@link #getDefaultAdapter(Context)} to get the default NFC
 * adapter for this Android device.
 *
 * <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>For more information about using NFC, read the
 * <a href="{@docRoot}guide/topics/nfc/index.html">Near Field Communication</a> developer guide.</p>
 * <p>To perform basic file sharing between devices, read
 * <a href="{@docRoot}training/beam-files/index.html">Sharing Files with NFC</a>.
 * </div>
 */
public final class NfcAdapter {
    static final String TAG = "NFC";

    
Intent to start an activity when a tag with NDEF payload is discovered.

The system inspects the first NdefRecord in the first NdefMessage and looks for a URI, SmartPoster, or MIME record. If a URI or SmartPoster record is found the intent will contain the URI in its data field. If a MIME record is found the intent will contain the MIME type in its type field. This allows activities to register IntentFilters targeting specific content on tags. Activities should register the most specific intent filters possible to avoid the activity chooser dialog, which can disrupt the interaction with the tag as the user interacts with the screen. 
If the tag has an NDEF payload this intent is started before ACTION_TECH_DISCOVERED. If any activities respond to this intent neither ACTION_TECH_DISCOVERED or ACTION_TAG_DISCOVERED will be started. 
The MIME type or data URI of this intent are normalized before dispatch -
so that MIME, URI scheme and URI host are always lower-case.

/**
     * Intent to start an activity when a tag with NDEF payload is discovered.
     *
     * <p>The system inspects the first {@link NdefRecord} in the first {@link NdefMessage} and
     * looks for a URI, SmartPoster, or MIME record. If a URI or SmartPoster record is found the
     * intent will contain the URI in its data field. If a MIME record is found the intent will
     * contain the MIME type in its type field. This allows activities to register
     * {@link IntentFilter}s targeting specific content on tags. Activities should register the
     * most specific intent filters possible to avoid the activity chooser dialog, which can
     * disrupt the interaction with the tag as the user interacts with the screen.
     *
     * <p>If the tag has an NDEF payload this intent is started before
     * {@link #ACTION_TECH_DISCOVERED}. If any activities respond to this intent neither
     * {@link #ACTION_TECH_DISCOVERED} or {@link #ACTION_TAG_DISCOVERED} will be started.
     *
     * <p>The MIME type or data URI of this intent are normalized before dispatch -
     * so that MIME, URI scheme and URI host are always lower-case.
     */
    @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
    public static final String ACTION_NDEF_DISCOVERED = "android.nfc.action.NDEF_DISCOVERED";

    
Intent to start an activity when a tag is discovered and activities are registered for the
specific technologies on the tag.

To receive this intent an activity must include an intent filter
for this action and specify the desired tech types in a
manifest meta-data entry. Here is an example manfiest entry:

<activity android:name=".nfc.TechFilter" android:label="NFC/TechFilter">
    <!-- Add a technology filter -->
    <intent-filter>
        <action android:name="android.nfc.action.TECH_DISCOVERED" />
    </intent-filter>
    <meta-data android:name="android.nfc.action.TECH_DISCOVERED"
        android:resource="@xml/filter_nfc"
    />
</activity>


The meta-data XML file should contain one or more tech-list entries
each consisting or one or more tech entries. The tech entries refer
to the qualified class name implementing the technology, for example "android.nfc.tech.NfcA".

A tag matches if any of the
tech-list sets is a subset of Tag.getTechList(). Each of the tech-lists is considered independently and the
activity is considered a match is any single tech-list matches the tag that was discovered. This provides AND and OR semantics for filtering desired techs. Here is an example that will match any tag using NfcF or any tag using NfcA, MifareClassic, and Ndef: 
<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
    <!-- capture anything using NfcF -->
    <tech-list>
        <tech>android.nfc.tech.NfcF</tech>
    </tech-list>
    <!-- OR -->
    <!-- capture all MIFARE Classics with NDEF payloads -->
    <tech-list>
        <tech>android.nfc.tech.NfcA</tech>
        <tech>android.nfc.tech.MifareClassic</tech>
        <tech>android.nfc.tech.Ndef</tech>
    </tech-list>
</resources>


This intent is started after ACTION_NDEF_DISCOVERED and before ACTION_TAG_DISCOVERED. If any activities respond to ACTION_NDEF_DISCOVERED this intent will not be started. If any activities respond to this intent ACTION_TAG_DISCOVERED will not be started. 
/**
     * Intent to start an activity when a tag is discovered and activities are registered for the
     * specific technologies on the tag.
     *
     * <p>To receive this intent an activity must include an intent filter
     * for this action and specify the desired tech types in a
     * manifest <code>meta-data</code> entry. Here is an example manfiest entry:
     * <pre>
     * &lt;activity android:name=".nfc.TechFilter" android:label="NFC/TechFilter"&gt;
     *     &lt;!-- Add a technology filter --&gt;
     *     &lt;intent-filter&gt;
     *         &lt;action android:name="android.nfc.action.TECH_DISCOVERED" /&gt;
     *     &lt;/intent-filter&gt;
     *
     *     &lt;meta-data android:name="android.nfc.action.TECH_DISCOVERED"
     *         android:resource="@xml/filter_nfc"
     *     /&gt;
     * &lt;/activity&gt;</pre>
     *
     * <p>The meta-data XML file should contain one or more <code>tech-list</code> entries
     * each consisting or one or more <code>tech</code> entries. The <code>tech</code> entries refer
     * to the qualified class name implementing the technology, for example "android.nfc.tech.NfcA".
     *
     * <p>A tag matches if any of the
     * <code>tech-list</code> sets is a subset of {@link Tag#getTechList() Tag.getTechList()}. Each
     * of the <code>tech-list</code>s is considered independently and the
     * activity is considered a match is any single <code>tech-list</code> matches the tag that was
     * discovered. This provides AND and OR semantics for filtering desired techs. Here is an
     * example that will match any tag using {@link NfcF} or any tag using {@link NfcA},
     * {@link MifareClassic}, and {@link Ndef}:
     *
     * <pre>
     * &lt;resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2"&gt;
     *     &lt;!-- capture anything using NfcF --&gt;
     *     &lt;tech-list&gt;
     *         &lt;tech&gt;android.nfc.tech.NfcF&lt;/tech&gt;
     *     &lt;/tech-list&gt;
     *
     *     &lt;!-- OR --&gt;
     *
     *     &lt;!-- capture all MIFARE Classics with NDEF payloads --&gt;
     *     &lt;tech-list&gt;
     *         &lt;tech&gt;android.nfc.tech.NfcA&lt;/tech&gt;
     *         &lt;tech&gt;android.nfc.tech.MifareClassic&lt;/tech&gt;
     *         &lt;tech&gt;android.nfc.tech.Ndef&lt;/tech&gt;
     *     &lt;/tech-list&gt;
     * &lt;/resources&gt;</pre>
     *
     * <p>This intent is started after {@link #ACTION_NDEF_DISCOVERED} and before
     * {@link #ACTION_TAG_DISCOVERED}. If any activities respond to {@link #ACTION_NDEF_DISCOVERED}
     * this intent will not be started. If any activities respond to this intent
     * {@link #ACTION_TAG_DISCOVERED} will not be started.
     */
    @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
    public static final String ACTION_TECH_DISCOVERED = "android.nfc.action.TECH_DISCOVERED";

    
Intent to start an activity when a tag is discovered.

This intent will not be started when a tag is discovered if any activities respond to ACTION_NDEF_DISCOVERED or ACTION_TECH_DISCOVERED for the current tag. 
/**
     * Intent to start an activity when a tag is discovered.
     *
     * <p>This intent will not be started when a tag is discovered if any activities respond to
     * {@link #ACTION_NDEF_DISCOVERED} or {@link #ACTION_TECH_DISCOVERED} for the current tag.
     */
    @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
    public static final String ACTION_TAG_DISCOVERED = "android.nfc.action.TAG_DISCOVERED";

    
Broadcast Action: Intent to notify an application that an transaction event has occurred
on the Secure Element.

This intent will only be sent if the application has requested permission for NFC_TRANSACTION_EVENT.NFC_TRANSACTION_EVENT and if the application has the necessary access to Secure Element which witnessed the particular event. 
/**
     * Broadcast Action: Intent to notify an application that an transaction event has occurred
     * on the Secure Element.
     *
     * <p>This intent will only be sent if the application has requested permission for
     * {@link android.Manifest.permission#NFC_TRANSACTION_EVENT} and if the application has the
     * necessary access to Secure Element which witnessed the particular event.
     */
    @RequiresPermission(android.Manifest.permission.NFC_TRANSACTION_EVENT)
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_TRANSACTION_DETECTED =
            "android.nfc.action.TRANSACTION_DETECTED";

    
Broadcast to only the activity that handles ACTION_TAG_DISCOVERED

@hide
/**
     * Broadcast to only the activity that handles ACTION_TAG_DISCOVERED
     * @hide
     */
    public static final String ACTION_TAG_LEFT_FIELD = "android.nfc.action.TAG_LOST";

    
Mandatory extra containing the Tag that was discovered for the ACTION_NDEF_DISCOVERED, ACTION_TECH_DISCOVERED, and ACTION_TAG_DISCOVERED intents. 
/**
     * Mandatory extra containing the {@link Tag} that was discovered for the
     * {@link #ACTION_NDEF_DISCOVERED}, {@link #ACTION_TECH_DISCOVERED}, and
     * {@link #ACTION_TAG_DISCOVERED} intents.
     */
    public static final String EXTRA_TAG = "android.nfc.extra.TAG";

    
Extra containing an array of NdefMessage present on the discovered tag.
 This extra is mandatory for ACTION_NDEF_DISCOVERED intents, and optional for ACTION_TECH_DISCOVERED, and ACTION_TAG_DISCOVERED intents.
 When this extra is present there will always be at least one NdefMessage element. Most NDEF tags have only one NDEF message, but we use an array for future compatibility. 
/**
     * Extra containing an array of {@link NdefMessage} present on the discovered tag.<p>
     * This extra is mandatory for {@link #ACTION_NDEF_DISCOVERED} intents,
     * and optional for {@link #ACTION_TECH_DISCOVERED}, and
     * {@link #ACTION_TAG_DISCOVERED} intents.<p>
     * When this extra is present there will always be at least one
     * {@link NdefMessage} element. Most NDEF tags have only one NDEF message,
     * but we use an array for future compatibility.
     */
    public static final String EXTRA_NDEF_MESSAGES = "android.nfc.extra.NDEF_MESSAGES";

    
Optional extra containing a byte array containing the ID of the discovered tag for the ACTION_NDEF_DISCOVERED, ACTION_TECH_DISCOVERED, and ACTION_TAG_DISCOVERED intents. 
/**
     * Optional extra containing a byte array containing the ID of the discovered tag for
     * the {@link #ACTION_NDEF_DISCOVERED}, {@link #ACTION_TECH_DISCOVERED}, and
     * {@link #ACTION_TAG_DISCOVERED} intents.
     */
    public static final String EXTRA_ID = "android.nfc.extra.ID";

    
Broadcast Action: The state of the local NFC adapter has been
changed.

For example, NFC has been turned on or off.

Always contains the extra field EXTRA_ADAPTER_STATE 
/**
     * Broadcast Action: The state of the local NFC adapter has been
     * changed.
     * <p>For example, NFC has been turned on or off.
     * <p>Always contains the extra field {@link #EXTRA_ADAPTER_STATE}
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_ADAPTER_STATE_CHANGED =
            "android.nfc.action.ADAPTER_STATE_CHANGED";

    
Used as an int extra field in ACTION_ADAPTER_STATE_CHANGED intents to request the current power state. Possible values are: STATE_OFF, STATE_TURNING_ON, STATE_ON, STATE_TURNING_OFF, 
/**
     * Used as an int extra field in {@link #ACTION_ADAPTER_STATE_CHANGED}
     * intents to request the current power state. Possible values are:
     * {@link #STATE_OFF},
     * {@link #STATE_TURNING_ON},
     * {@link #STATE_ON},
     * {@link #STATE_TURNING_OFF},
     */
    public static final String EXTRA_ADAPTER_STATE = "android.nfc.extra.ADAPTER_STATE";

    
Mandatory byte[] extra field in ACTION_TRANSACTION_DETECTED 
/**
     * Mandatory byte[] extra field in {@link #ACTION_TRANSACTION_DETECTED}
     */
    public static final String EXTRA_AID = "android.nfc.extra.AID";

    
Optional byte[] extra field in ACTION_TRANSACTION_DETECTED 
/**
     * Optional byte[] extra field in {@link #ACTION_TRANSACTION_DETECTED}
     */
    public static final String EXTRA_DATA = "android.nfc.extra.DATA";

    
Mandatory String extra field in ACTION_TRANSACTION_DETECTED Indicates the Secure Element on which the transaction occurred. eSE1...eSEn for Embedded Secure Elements, SIM1...SIMn for UICC, etc. 
/**
     * Mandatory String extra field in {@link #ACTION_TRANSACTION_DETECTED}
     * Indicates the Secure Element on which the transaction occurred.
     * eSE1...eSEn for Embedded Secure Elements, SIM1...SIMn for UICC, etc.
     */
    public static final String EXTRA_SECURE_ELEMENT_NAME = "android.nfc.extra.SECURE_ELEMENT_NAME";

    public static final int STATE_OFF = 1;
    public static final int STATE_TURNING_ON = 2;
    public static final int STATE_ON = 3;
    public static final int STATE_TURNING_OFF = 4;

    
Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this flag enables polling for Nfc-A technology.

/**
     * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this flag enables polling for Nfc-A technology.
     */
    public static final int FLAG_READER_NFC_A = 0x1;

    
Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this flag enables polling for Nfc-B technology.

/**
     * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this flag enables polling for Nfc-B technology.
     */
    public static final int FLAG_READER_NFC_B = 0x2;

    
Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this flag enables polling for Nfc-F technology.

/**
     * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this flag enables polling for Nfc-F technology.
     */
    public static final int FLAG_READER_NFC_F = 0x4;

    
Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this flag enables polling for Nfc-V (ISO15693) technology.

/**
     * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this flag enables polling for Nfc-V (ISO15693) technology.
     */
    public static final int FLAG_READER_NFC_V = 0x8;

    
Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this flag enables polling for NfcBarcode technology.

/**
     * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this flag enables polling for NfcBarcode technology.
     */
    public static final int FLAG_READER_NFC_BARCODE = 0x10;

    
Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this flag allows the caller to prevent the
platform from performing an NDEF check on the tags it
finds.

/**
     * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this flag allows the caller to prevent the
     * platform from performing an NDEF check on the tags it
     * finds.
     */
    public static final int FLAG_READER_SKIP_NDEF_CHECK = 0x80;

    
Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this flag allows the caller to prevent the
platform from playing sounds when it discovers a tag.

/**
     * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this flag allows the caller to prevent the
     * platform from playing sounds when it discovers a tag.
     */
    public static final int FLAG_READER_NO_PLATFORM_SOUNDS = 0x100;

    
Int Extra for use with enableReaderMode(Activity, ReaderCallback, int, Bundle). 

Setting this integer extra allows the calling application to specify
the delay that the platform will use for performing presence checks
on any discovered tag.

/**
     * Int Extra for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
     * <p>
     * Setting this integer extra allows the calling application to specify
     * the delay that the platform will use for performing presence checks
     * on any discovered tag.
     */
    public static final String EXTRA_READER_PRESENCE_CHECK_DELAY = "presence";

    
@hide
/** @hide */
    @SystemApi
    public static final int FLAG_NDEF_PUSH_NO_CONFIRM = 0x1;

    
@hide
/** @hide */
    public static final String ACTION_HANDOVER_TRANSFER_STARTED =
            "android.nfc.action.HANDOVER_TRANSFER_STARTED";

    
@hide
/** @hide */
    public static final String ACTION_HANDOVER_TRANSFER_DONE =
            "android.nfc.action.HANDOVER_TRANSFER_DONE";

    
@hide
/** @hide */
    public static final String EXTRA_HANDOVER_TRANSFER_STATUS =
            "android.nfc.extra.HANDOVER_TRANSFER_STATUS";

    
@hide
/** @hide */
    public static final int HANDOVER_TRANSFER_STATUS_SUCCESS = 0;
    
@hide
/** @hide */
    public static final int HANDOVER_TRANSFER_STATUS_FAILURE = 1;

    
@hide
/** @hide */
    public static final String EXTRA_HANDOVER_TRANSFER_URI =
            "android.nfc.extra.HANDOVER_TRANSFER_URI";

    // Guarded by NfcAdapter.class
    static boolean sIsInitialized = false;
    static boolean sHasNfcFeature;

    // Final after first constructor, except for
    // attemptDeadServiceRecovery() when NFC crashes - we accept a best effort
    // recovery
    static INfcAdapter sService;
    static INfcTag sTagService;
    static INfcCardEmulation sCardEmulationService;
    static INfcFCardEmulation sNfcFCardEmulationService;

    
The NfcAdapter object for each application context.
There is a 1-1 relationship between application context and
NfcAdapter object.

/**
     * The NfcAdapter object for each application context.
     * There is a 1-1 relationship between application context and
     * NfcAdapter object.
     */
    static HashMap<Context, NfcAdapter> sNfcAdapters = new HashMap(); //guard by NfcAdapter.class

    
NfcAdapter used with a null context. This ctor was deprecated but we have
to support it for backwards compatibility. New methods that require context
might throw when called on the null-context NfcAdapter.

/**
     * NfcAdapter used with a null context. This ctor was deprecated but we have
     * to support it for backwards compatibility. New methods that require context
     * might throw when called on the null-context NfcAdapter.
     */
    static NfcAdapter sNullContextNfcAdapter;  // protected by NfcAdapter.class

    final NfcActivityManager mNfcActivityManager;
    final Context mContext;
    final HashMap<NfcUnlockHandler, INfcUnlockHandler> mNfcUnlockHandlers;
    final Object mLock;

    ITagRemovedCallback mTagRemovedListener; // protected by mLock

    
A callback to be invoked when the system finds a tag while the foreground activity is
operating in reader mode.

Register your ReaderCallback implementation with NfcAdapter.enableReaderMode and disable it with NfcAdapter.disableReaderMode. 
See Also:
/**
     * A callback to be invoked when the system finds a tag while the foreground activity is
     * operating in reader mode.
     * <p>Register your {@code ReaderCallback} implementation with {@link
     * NfcAdapter#enableReaderMode} and disable it with {@link
     * NfcAdapter#disableReaderMode}.
     * @see NfcAdapter#enableReaderMode
     */
    public interface ReaderCallback {
        public void onTagDiscovered(Tag tag);
    }

    
A callback to be invoked when the system successfully delivers your NdefMessage to another device. 
See Also:
  • setOnNdefPushCompleteCallback
/**
     * A callback to be invoked when the system successfully delivers your {@link NdefMessage}
     * to another device.
     * @see #setOnNdefPushCompleteCallback
     */
    public interface OnNdefPushCompleteCallback {
        
Called on successful NDEF push.

This callback is usually made on a binder thread (not the UI thread).

Params:
See Also:
  • setNdefPushMessageCallback
/**
         * Called on successful NDEF push.
         *
         * <p>This callback is usually made on a binder thread (not the UI thread).
         *
         * @param event {@link NfcEvent} with the {@link NfcEvent#nfcAdapter} field set
         * @see #setNdefPushMessageCallback
         */
        public void onNdefPushComplete(NfcEvent event);
    }

    
A callback to be invoked when another NFC device capable of NDEF push (Android Beam)
is within range.

Implement this interface and pass it to setNdefPushMessageCallback() in order to create an NdefMessage at the moment that another device is within range for NFC. Using this callback allows you to create a message with data that might vary based on the content currently visible to the user. Alternatively, you can call setNdefPushMessage() if the NdefMessage always contains the same data. 
/**
     * A callback to be invoked when another NFC device capable of NDEF push (Android Beam)
     * is within range.
     * <p>Implement this interface and pass it to {@link
     * NfcAdapter#setNdefPushMessageCallback setNdefPushMessageCallback()} in order to create an
     * {@link NdefMessage} at the moment that another device is within range for NFC. Using this
     * callback allows you to create a message with data that might vary based on the
     * content currently visible to the user. Alternatively, you can call {@link
     * #setNdefPushMessage setNdefPushMessage()} if the {@link NdefMessage} always contains the
     * same data.
     */
    public interface CreateNdefMessageCallback {
        
Called to provide a NdefMessage to push. 
This callback is usually made on a binder thread (not the UI thread).

Called when this device is in range of another device
that might support NDEF push. It allows the application to
create the NDEF message only when it is required.

NDEF push cannot occur until this method returns, so do not
block for too long.

The Android operating system will usually show a system UI
on top of your activity during this time, so do not try to request
input from the user to complete the callback, or provide custom NDEF
push UI. The user probably will not see it.

Params:
Returns:NDEF message to push, or null to not provide a message
/**
         * Called to provide a {@link NdefMessage} to push.
         *
         * <p>This callback is usually made on a binder thread (not the UI thread).
         *
         * <p>Called when this device is in range of another device
         * that might support NDEF push. It allows the application to
         * create the NDEF message only when it is required.
         *
         * <p>NDEF push cannot occur until this method returns, so do not
         * block for too long.
         *
         * <p>The Android operating system will usually show a system UI
         * on top of your activity during this time, so do not try to request
         * input from the user to complete the callback, or provide custom NDEF
         * push UI. The user probably will not see it.
         *
         * @param event {@link NfcEvent} with the {@link NfcEvent#nfcAdapter} field set
         * @return NDEF message to push, or null to not provide a message
         */
        public NdefMessage createNdefMessage(NfcEvent event);
    }


    // TODO javadoc
    public interface CreateBeamUrisCallback {
        public Uri[] createBeamUris(NfcEvent event);
    }

    
A callback that is invoked when a tag is removed from the field.

See Also:
  • ignore.ignore
/**
     * A callback that is invoked when a tag is removed from the field.
     * @see NfcAdapter#ignore
     */
    public interface OnTagRemovedListener {
        void onTagRemoved();
    }

    
A callback to be invoked when an application has registered as a
handler to unlock the device given an NFC tag at the lockscreen.

@hide
/**
     * A callback to be invoked when an application has registered as a
     * handler to unlock the device given an NFC tag at the lockscreen.
     * @hide
     */
    @SystemApi
    public interface NfcUnlockHandler {
        
Called at the lock screen to attempt to unlock the device with the given tag.

Params:
  • tag – the detected tag, to be used to unlock the device
Returns:true if the device was successfully unlocked
/**
         * Called at the lock screen to attempt to unlock the device with the given tag.
         * @param tag the detected tag, to be used to unlock the device
         * @return true if the device was successfully unlocked
         */
        public boolean onUnlockAttempted(Tag tag);
    }


    
Helper to check if this device has FEATURE_NFC, but without using
a context.
Equivalent to
context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_NFC)

/**
     * Helper to check if this device has FEATURE_NFC, but without using
     * a context.
     * Equivalent to
     * context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_NFC)
     */
    private static boolean hasNfcFeature() {
        IPackageManager pm = ActivityThread.getPackageManager();
        if (pm == null) {
            Log.e(TAG, "Cannot get package manager, assuming no NFC feature");
            return false;
        }
        try {
            return pm.hasSystemFeature(PackageManager.FEATURE_NFC, 0);
        } catch (RemoteException e) {
            Log.e(TAG, "Package manager query failed, assuming no NFC feature", e);
            return false;
        }
    }

    
Helper to check if this device is NFC HCE capable, by checking for
FEATURE_NFC_HOST_CARD_EMULATION and/or FEATURE_NFC_HOST_CARD_EMULATION_NFCF,
but without using a context.

/**
     * Helper to check if this device is NFC HCE capable, by checking for
     * FEATURE_NFC_HOST_CARD_EMULATION and/or FEATURE_NFC_HOST_CARD_EMULATION_NFCF,
     * but without using a context.
     */
    private static boolean hasNfcHceFeature() {
        IPackageManager pm = ActivityThread.getPackageManager();
        if (pm == null) {
            Log.e(TAG, "Cannot get package manager, assuming no NFC feature");
            return false;
        }
        try {
            return pm.hasSystemFeature(PackageManager.FEATURE_NFC_HOST_CARD_EMULATION, 0)
                || pm.hasSystemFeature(PackageManager.FEATURE_NFC_HOST_CARD_EMULATION_NFCF, 0);
        } catch (RemoteException e) {
            Log.e(TAG, "Package manager query failed, assuming no NFC feature", e);
            return false;
        }
    }

    
Returns the NfcAdapter for application context,
or throws if NFC is not available.

@hide
/**
     * Returns the NfcAdapter for application context,
     * or throws if NFC is not available.
     * @hide
     */
    public static synchronized NfcAdapter getNfcAdapter(Context context) {
        if (!sIsInitialized) {
            sHasNfcFeature = hasNfcFeature();
            boolean hasHceFeature = hasNfcHceFeature();
            /* is this device meant to have NFC */
            if (!sHasNfcFeature && !hasHceFeature) {
                Log.v(TAG, "this device does not have NFC support");
                throw new UnsupportedOperationException();
            }
            sService = getServiceInterface();
            if (sService == null) {
                Log.e(TAG, "could not retrieve NFC service");
                throw new UnsupportedOperationException();
            }
            if (sHasNfcFeature) {
                try {
                    sTagService = sService.getNfcTagInterface();
                } catch (RemoteException e) {
                    Log.e(TAG, "could not retrieve NFC Tag service");
                    throw new UnsupportedOperationException();
                }
            }
            if (hasHceFeature) {
                try {
                    sNfcFCardEmulationService = sService.getNfcFCardEmulationInterface();
                } catch (RemoteException e) {
                    Log.e(TAG, "could not retrieve NFC-F card emulation service");
                    throw new UnsupportedOperationException();
                }
                try {
                    sCardEmulationService = sService.getNfcCardEmulationInterface();
                } catch (RemoteException e) {
                    Log.e(TAG, "could not retrieve card emulation service");
                    throw new UnsupportedOperationException();
                }
            }

            sIsInitialized = true;
        }
        if (context == null) {
            if (sNullContextNfcAdapter == null) {
                sNullContextNfcAdapter = new NfcAdapter(null);
            }
            return sNullContextNfcAdapter;
        }
        NfcAdapter adapter = sNfcAdapters.get(context);
        if (adapter == null) {
            adapter = new NfcAdapter(context);
            sNfcAdapters.put(context, adapter);
        }
        return adapter;
    }

    
get handle to NFC service interface 
/** get handle to NFC service interface */
    private static INfcAdapter getServiceInterface() {
        /* get a handle to NFC service */
        IBinder b = ServiceManager.getService("nfc");
        if (b == null) {
            return null;
        }
        return INfcAdapter.Stub.asInterface(b);
    }

    
Helper to get the default NFC Adapter.


Most Android devices will only have one NFC Adapter (NFC Controller).


This helper is the equivalent of:

NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
NfcAdapter adapter = manager.getDefaultAdapter();


Params:
  • context – the calling application's context
Returns:the default NFC adapter, or null if no NFC adapter exists
/**
     * Helper to get the default NFC Adapter.
     * <p>
     * Most Android devices will only have one NFC Adapter (NFC Controller).
     * <p>
     * This helper is the equivalent of:
     * <pre>
     * NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
     * NfcAdapter adapter = manager.getDefaultAdapter();</pre>
     * @param context the calling application's context
     *
     * @return the default NFC adapter, or null if no NFC adapter exists
     */
    public static NfcAdapter getDefaultAdapter(Context context) {
        if (context == null) {
            throw new IllegalArgumentException("context cannot be null");
        }
        context = context.getApplicationContext();
        if (context == null) {
            throw new IllegalArgumentException(
                    "context not associated with any application (using a mock context?)");
        }
        /* use getSystemService() for consistency */
        NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
        if (manager == null) {
            // NFC not available
            return null;
        }
        return manager.getDefaultAdapter();
    }

    
Legacy NfcAdapter getter, always use getDefaultAdapter(Context) instead.

This method was deprecated at API level 10 (Gingerbread MR1) because a context is required
for many NFC API methods. Those methods will fail when called on an NfcAdapter
object created from this method.


Deprecated:use getDefaultAdapter(Context)
@hide
/**
     * Legacy NfcAdapter getter, always use {@link #getDefaultAdapter(Context)} instead.<p>
     * This method was deprecated at API level 10 (Gingerbread MR1) because a context is required
     * for many NFC API methods. Those methods will fail when called on an NfcAdapter
     * object created from this method.<p>
     * @deprecated use {@link #getDefaultAdapter(Context)}
     * @hide
     */
    @Deprecated
    public static NfcAdapter getDefaultAdapter() {
        // introduced in API version 9 (GB 2.3)
        // deprecated in API version 10 (GB 2.3.3)
        // removed from public API in version 16 (ICS MR2)
        // should maintain as a hidden API for binary compatibility for a little longer
        Log.w(TAG, "WARNING: NfcAdapter.getDefaultAdapter() is deprecated, use " +
                "NfcAdapter.getDefaultAdapter(Context) instead", new Exception());

        return NfcAdapter.getNfcAdapter(null);
    }

    NfcAdapter(Context context) {
        mContext = context;
        mNfcActivityManager = new NfcActivityManager(this);
        mNfcUnlockHandlers = new HashMap<NfcUnlockHandler, INfcUnlockHandler>();
        mTagRemovedListener = null;
        mLock = new Object();
    }

    
@hide
/**
     * @hide
     */
    public Context getContext() {
        return mContext;
    }

    
Returns the binder interface to the service.

@hide
/**
     * Returns the binder interface to the service.
     * @hide
     */
    public INfcAdapter getService() {
        isEnabled();  // NOP call to recover sService if it is stale
        return sService;
    }

    
Returns the binder interface to the tag service.

@hide
/**
     * Returns the binder interface to the tag service.
     * @hide
     */
    public INfcTag getTagService() {
        isEnabled();  // NOP call to recover sTagService if it is stale
        return sTagService;
    }

    
Returns the binder interface to the card emulation service.

@hide
/**
     * Returns the binder interface to the card emulation service.
     * @hide
     */
    public INfcCardEmulation getCardEmulationService() {
        isEnabled();
        return sCardEmulationService;
    }

    
Returns the binder interface to the NFC-F card emulation service.

@hide
/**
     * Returns the binder interface to the NFC-F card emulation service.
     * @hide
     */
    public INfcFCardEmulation getNfcFCardEmulationService() {
        isEnabled();
        return sNfcFCardEmulationService;
    }

    
Returns the binder interface to the NFC-DTA test interface.

@hide
/**
     * Returns the binder interface to the NFC-DTA test interface.
     * @hide
     */
    public INfcDta getNfcDtaInterface() {
        if (mContext == null) {
            throw new UnsupportedOperationException("You need a context on NfcAdapter to use the "
                    + " NFC extras APIs");
        }
        try {
            return sService.getNfcDtaInterface(mContext.getPackageName());
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return null;
        }
    }

    
NFC service dead - attempt best effort recovery

@hide
/**
     * NFC service dead - attempt best effort recovery
     * @hide
     */
    public void attemptDeadServiceRecovery(Exception e) {
        Log.e(TAG, "NFC service dead - attempting to recover", e);
        INfcAdapter service = getServiceInterface();
        if (service == null) {
            Log.e(TAG, "could not retrieve NFC service during service recovery");
            // nothing more can be done now, sService is still stale, we'll hit
            // this recovery path again later
            return;
        }
        // assigning to sService is not thread-safe, but this is best-effort code
        // and on a well-behaved system should never happen
        sService = service;
        try {
            sTagService = service.getNfcTagInterface();
        } catch (RemoteException ee) {
            Log.e(TAG, "could not retrieve NFC tag service during service recovery");
            // nothing more can be done now, sService is still stale, we'll hit
            // this recovery path again later
            return;
        }

        try {
            sCardEmulationService = service.getNfcCardEmulationInterface();
        } catch (RemoteException ee) {
            Log.e(TAG, "could not retrieve NFC card emulation service during service recovery");
        }

        try {
            sNfcFCardEmulationService = service.getNfcFCardEmulationInterface();
        } catch (RemoteException ee) {
            Log.e(TAG, "could not retrieve NFC-F card emulation service during service recovery");
        }

        return;
    }

    
Return true if this NFC Adapter has any features enabled.

If this method returns false, the NFC hardware is guaranteed not to
generate or respond to any NFC communication over its NFC radio.

Applications can use this to check if NFC is enabled. Applications
can request Settings UI allowing the user to toggle NFC using:

startActivity(new Intent(Settings.ACTION_NFC_SETTINGS))


See Also:
  • ACTION_NFC_SETTINGS.ACTION_NFC_SETTINGS
Returns:true if this NFC Adapter has any features enabled
/**
     * Return true if this NFC Adapter has any features enabled.
     *
     * <p>If this method returns false, the NFC hardware is guaranteed not to
     * generate or respond to any NFC communication over its NFC radio.
     * <p>Applications can use this to check if NFC is enabled. Applications
     * can request Settings UI allowing the user to toggle NFC using:
     * <p><pre>startActivity(new Intent(Settings.ACTION_NFC_SETTINGS))</pre>
     *
     * @see android.provider.Settings#ACTION_NFC_SETTINGS
     * @return true if this NFC Adapter has any features enabled
     */
    public boolean isEnabled() {
        try {
            return sService.getState() == STATE_ON;
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Return the state of this NFC Adapter.

Returns one of STATE_ON, STATE_TURNING_ON, STATE_OFF, STATE_TURNING_OFF. 
isEnabled() is equivalent to getAdapterState() == STATE_ON

Returns:the current state of this NFC adapter
@hide
/**
     * Return the state of this NFC Adapter.
     *
     * <p>Returns one of {@link #STATE_ON}, {@link #STATE_TURNING_ON},
     * {@link #STATE_OFF}, {@link #STATE_TURNING_OFF}.
     *
     * <p>{@link #isEnabled()} is equivalent to
     * <code>{@link #getAdapterState()} == {@link #STATE_ON}</code>
     *
     * @return the current state of this NFC adapter
     *
     * @hide
     */
    public int getAdapterState() {
        try {
            return sService.getState();
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return NfcAdapter.STATE_OFF;
        }
    }

    
Enable NFC hardware.

This call is asynchronous. Listen for ACTION_ADAPTER_STATE_CHANGED broadcasts to find out when the operation is complete. 
If this returns true, then either NFC is already on, or a ACTION_ADAPTER_STATE_CHANGED broadcast will be sent to indicate a state transition. If this returns false, then there is some problem that prevents an attempt to turn NFC on (for example we are in airplane mode and NFC is not toggleable in airplane mode on this platform). 
@hide
/**
     * Enable NFC hardware.
     *
     * <p>This call is asynchronous. Listen for
     * {@link #ACTION_ADAPTER_STATE_CHANGED} broadcasts to find out when the
     * operation is complete.
     *
     * <p>If this returns true, then either NFC is already on, or
     * a {@link #ACTION_ADAPTER_STATE_CHANGED} broadcast will be sent
     * to indicate a state transition. If this returns false, then
     * there is some problem that prevents an attempt to turn
     * NFC on (for example we are in airplane mode and NFC is not
     * toggleable in airplane mode on this platform).
     *
     * @hide
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
    public boolean enable() {
        try {
            return sService.enable();
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Disable NFC hardware.

No NFC features will work after this call, and the hardware
will not perform or respond to any NFC communication.

This call is asynchronous. Listen for ACTION_ADAPTER_STATE_CHANGED broadcasts to find out when the operation is complete. 
If this returns true, then either NFC is already off, or a ACTION_ADAPTER_STATE_CHANGED broadcast will be sent to indicate a state transition. If this returns false, then there is some problem that prevents an attempt to turn NFC off. 
@hide
/**
     * Disable NFC hardware.
     *
     * <p>No NFC features will work after this call, and the hardware
     * will not perform or respond to any NFC communication.
     *
     * <p>This call is asynchronous. Listen for
     * {@link #ACTION_ADAPTER_STATE_CHANGED} broadcasts to find out when the
     * operation is complete.
     *
     * <p>If this returns true, then either NFC is already off, or
     * a {@link #ACTION_ADAPTER_STATE_CHANGED} broadcast will be sent
     * to indicate a state transition. If this returns false, then
     * there is some problem that prevents an attempt to turn
     * NFC off.
     *
     * @hide
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
    public boolean disable() {
        try {
            return sService.disable(true);
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Disable NFC hardware.

@hide
/**
     * Disable NFC hardware.
     * @hide
    */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
    public boolean disable(boolean persist) {
        try {
            return sService.disable(persist);
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Pauses polling for a timeoutInMs millis. If polling must be resumed before timeout, use resumePolling(). 
@hide
/**
     * Pauses polling for a {@code timeoutInMs} millis. If polling must be resumed before timeout,
     * use {@link #resumePolling()}.
     * @hide
     */
    public void pausePolling(int timeoutInMs) {
        try {
            sService.pausePolling(timeoutInMs);
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
        }
    }

    
Resumes default polling for the current device state if polling is paused. Calling
this while polling is not paused is a no-op.

@hide
/**
     * Resumes default polling for the current device state if polling is paused. Calling
     * this while polling is not paused is a no-op.
     *
     * @hide
     */
    public void resumePolling() {
        try {
            sService.resumePolling();
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
        }
    }

    
Set one or more Uris to send using Android Beam (TM). Every Uri you provide must have either scheme 'file' or scheme 'content'. 
For the data provided through this method, Android Beam tries to
switch to alternate transports such as Bluetooth to achieve a fast
transfer speed. Hence this method is very suitable
for transferring large files such as pictures or songs.

The receiving side will store the content of each Uri in a file and present a notification to the user to open the file with a Intent with action Intent.ACTION_VIEW. If multiple URIs are sent, the Intent will refer to the first of the stored files. 
This method may be called at any time before Activity.onDestroy, but the URI(s) are only made available for Android Beam when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's Activity.onCreate - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread. 
setBeamPushUris and setBeamPushUrisCallback have priority over both setNdefPushMessage and setNdefPushMessageCallback. 
If setBeamPushUris is called with a null Uri array, and/or setBeamPushUrisCallback is called with a null callback, then the Uri push will be completely disabled for the specified activity(s). 
Code example:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
    if (nfcAdapter == null) return;  // NFC not available on this device
    nfcAdapter.setBeamPushUris(new Uri[] {uri1, uri2}, this);
}

And that is it. Only one call per activity is necessary. The Android
OS will automatically release its references to the Uri(s) and the
Activity object when it is destroyed if you follow this pattern.

If your Activity wants to dynamically supply Uri(s), then set a callback using setBeamPushUrisCallback instead of using this method. 
Do not pass in an Activity that has already been through Activity.onDestroy. This is guaranteed if you call this API during Activity.onCreate. 
If this device does not support alternate transports
such as Bluetooth or WiFI, calling this method does nothing.

Requires the NFC.NFC permission. 
Params:
  • uris – an array of Uri(s) to push over Android Beam
  • activity – activity for which the Uri(s) will be pushed
Throws:
/**
     * Set one or more {@link Uri}s to send using Android Beam (TM). Every
     * Uri you provide must have either scheme 'file' or scheme 'content'.
     *
     * <p>For the data provided through this method, Android Beam tries to
     * switch to alternate transports such as Bluetooth to achieve a fast
     * transfer speed. Hence this method is very suitable
     * for transferring large files such as pictures or songs.
     *
     * <p>The receiving side will store the content of each Uri in
     * a file and present a notification to the user to open the file
     * with a {@link android.content.Intent} with action
     * {@link android.content.Intent#ACTION_VIEW}.
     * If multiple URIs are sent, the {@link android.content.Intent} will refer
     * to the first of the stored files.
     *
     * <p>This method may be called at any time before {@link Activity#onDestroy},
     * but the URI(s) are only made available for Android Beam when the
     * specified activity(s) are in resumed (foreground) state. The recommended
     * approach is to call this method during your Activity's
     * {@link Activity#onCreate} - see sample
     * code below. This method does not immediately perform any I/O or blocking work,
     * so is safe to call on your main thread.
     *
     * <p>{@link #setBeamPushUris} and {@link #setBeamPushUrisCallback}
     * have priority over both {@link #setNdefPushMessage} and
     * {@link #setNdefPushMessageCallback}.
     *
     * <p>If {@link #setBeamPushUris} is called with a null Uri array,
     * and/or {@link #setBeamPushUrisCallback} is called with a null callback,
     * then the Uri push will be completely disabled for the specified activity(s).
     *
     * <p>Code example:
     * <pre>
     * protected void onCreate(Bundle savedInstanceState) {
     *     super.onCreate(savedInstanceState);
     *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     *     if (nfcAdapter == null) return;  // NFC not available on this device
     *     nfcAdapter.setBeamPushUris(new Uri[] {uri1, uri2}, this);
     * }</pre>
     * And that is it. Only one call per activity is necessary. The Android
     * OS will automatically release its references to the Uri(s) and the
     * Activity object when it is destroyed if you follow this pattern.
     *
     * <p>If your Activity wants to dynamically supply Uri(s),
     * then set a callback using {@link #setBeamPushUrisCallback} instead
     * of using this method.
     *
     * <p class="note">Do not pass in an Activity that has already been through
     * {@link Activity#onDestroy}. This is guaranteed if you call this API
     * during {@link Activity#onCreate}.
     *
     * <p class="note">If this device does not support alternate transports
     * such as Bluetooth or WiFI, calling this method does nothing.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param uris an array of Uri(s) to push over Android Beam
     * @param activity activity for which the Uri(s) will be pushed
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void setBeamPushUris(Uri[] uris, Activity activity) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        if (activity == null) {
            throw new NullPointerException("activity cannot be null");
        }
        if (uris != null) {
            for (Uri uri : uris) {
                if (uri == null) throw new NullPointerException("Uri not " +
                        "allowed to be null");
                String scheme = uri.getScheme();
                if (scheme == null || (!scheme.equalsIgnoreCase("file") &&
                        !scheme.equalsIgnoreCase("content"))) {
                    throw new IllegalArgumentException("URI needs to have " +
                            "either scheme file or scheme content");
                }
            }
        }
        mNfcActivityManager.setNdefPushContentUri(activity, uris);
    }

    
Set a callback that will dynamically generate one or more Uris to send using Android Beam (TM). Every Uri the callback provides must have either scheme 'file' or scheme 'content'. 
For the data provided through this callback, Android Beam tries to
switch to alternate transports such as Bluetooth to achieve a fast
transfer speed. Hence this method is very suitable
for transferring large files such as pictures or songs.

The receiving side will store the content of each Uri in a file and present a notification to the user to open the file with a Intent with action Intent.ACTION_VIEW. If multiple URIs are sent, the Intent will refer to the first of the stored files. 
This method may be called at any time before Activity.onDestroy, but the URI(s) are only made available for Android Beam when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's Activity.onCreate - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread. 
setBeamPushUris and setBeamPushUrisCallback have priority over both setNdefPushMessage and setNdefPushMessageCallback. 
If setBeamPushUris is called with a null Uri array, and/or setBeamPushUrisCallback is called with a null callback, then the Uri push will be completely disabled for the specified activity(s). 
Code example:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
    if (nfcAdapter == null) return;  // NFC not available on this device
    nfcAdapter.setBeamPushUrisCallback(callback, this);
}

And that is it. Only one call per activity is necessary. The Android
OS will automatically release its references to the Uri(s) and the
Activity object when it is destroyed if you follow this pattern.

Do not pass in an Activity that has already been through Activity.onDestroy. This is guaranteed if you call this API during Activity.onCreate. 
If this device does not support alternate transports
such as Bluetooth or WiFI, calling this method does nothing.

Requires the NFC.NFC permission. 
Params:
  • callback – callback, or null to disable
  • activity – activity for which the Uri(s) will be pushed
Throws:
/**
     * Set a callback that will dynamically generate one or more {@link Uri}s
     * to send using Android Beam (TM). Every Uri the callback provides
     * must have either scheme 'file' or scheme 'content'.
     *
     * <p>For the data provided through this callback, Android Beam tries to
     * switch to alternate transports such as Bluetooth to achieve a fast
     * transfer speed. Hence this method is very suitable
     * for transferring large files such as pictures or songs.
     *
     * <p>The receiving side will store the content of each Uri in
     * a file and present a notification to the user to open the file
     * with a {@link android.content.Intent} with action
     * {@link android.content.Intent#ACTION_VIEW}.
     * If multiple URIs are sent, the {@link android.content.Intent} will refer
     * to the first of the stored files.
     *
     * <p>This method may be called at any time before {@link Activity#onDestroy},
     * but the URI(s) are only made available for Android Beam when the
     * specified activity(s) are in resumed (foreground) state. The recommended
     * approach is to call this method during your Activity's
     * {@link Activity#onCreate} - see sample
     * code below. This method does not immediately perform any I/O or blocking work,
     * so is safe to call on your main thread.
     *
     * <p>{@link #setBeamPushUris} and {@link #setBeamPushUrisCallback}
     * have priority over both {@link #setNdefPushMessage} and
     * {@link #setNdefPushMessageCallback}.
     *
     * <p>If {@link #setBeamPushUris} is called with a null Uri array,
     * and/or {@link #setBeamPushUrisCallback} is called with a null callback,
     * then the Uri push will be completely disabled for the specified activity(s).
     *
     * <p>Code example:
     * <pre>
     * protected void onCreate(Bundle savedInstanceState) {
     *     super.onCreate(savedInstanceState);
     *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     *     if (nfcAdapter == null) return;  // NFC not available on this device
     *     nfcAdapter.setBeamPushUrisCallback(callback, this);
     * }</pre>
     * And that is it. Only one call per activity is necessary. The Android
     * OS will automatically release its references to the Uri(s) and the
     * Activity object when it is destroyed if you follow this pattern.
     *
     * <p class="note">Do not pass in an Activity that has already been through
     * {@link Activity#onDestroy}. This is guaranteed if you call this API
     * during {@link Activity#onCreate}.
     *
     * <p class="note">If this device does not support alternate transports
     * such as Bluetooth or WiFI, calling this method does nothing.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param callback callback, or null to disable
     * @param activity activity for which the Uri(s) will be pushed
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void setBeamPushUrisCallback(CreateBeamUrisCallback callback, Activity activity) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        if (activity == null) {
            throw new NullPointerException("activity cannot be null");
        }
        mNfcActivityManager.setNdefPushContentUriCallback(activity, callback);
    }

    
Set a static NdefMessage to send using Android Beam (TM). 
This method may be called at any time before Activity.onDestroy, but the NDEF message is only made available for NDEF push when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's Activity.onCreate - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread. 
Only one NDEF message can be pushed by the currently resumed activity. If both setNdefPushMessage and setNdefPushMessageCallback are set, then the callback will take priority. 
If neither setNdefPushMessage or setNdefPushMessageCallback have been called for your activity, then the Android OS may choose to send a default NDEF message on your behalf, such as a URI for your application. 
If setNdefPushMessage is called with a null NDEF message, and/or setNdefPushMessageCallback is called with a null callback, then NDEF push will be completely disabled for the specified activity(s). This also disables any default NDEF message the Android OS would have otherwise sent on your behalf for those activity(s). 
If you want to prevent the Android OS from sending default NDEF messages completely (for all activities), you can include a <meta-data> element inside the <application> element of your AndroidManifest.xml file, like this: 
<application ...>
    <meta-data android:name="android.nfc.disable_beam_default"
        android:value="true" />
</application>


The API allows for multiple activities to be specified at a time, but it is strongly recommended to just register one at a time, and to do so during the activity's Activity.onCreate. For example: 
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
    if (nfcAdapter == null) return;  // NFC not available on this device
    nfcAdapter.setNdefPushMessage(ndefMessage, this);
}

And that is it. Only one call per activity is necessary. The Android
OS will automatically release its references to the NDEF message and the
Activity object when it is destroyed if you follow this pattern.

If your Activity wants to dynamically generate an NDEF message, then set a callback using setNdefPushMessageCallback instead of a static message. 
Do not pass in an Activity that has already been through Activity.onDestroy. This is guaranteed if you call this API during Activity.onCreate. 
For sending large content such as pictures and songs, consider using setBeamPushUris, which switches to alternate transports such as Bluetooth to achieve a fast transfer rate. 
Requires the NFC.NFC permission. 
Params:
  • message – NDEF message to push over NFC, or null to disable
  • activity – activity for which the NDEF message will be pushed
  • activities – optional additional activities, however we strongly recommend to only register one at a time, and to do so in that activity's Activity.onCreate
Throws:
/**
     * Set a static {@link NdefMessage} to send using Android Beam (TM).
     *
     * <p>This method may be called at any time before {@link Activity#onDestroy},
     * but the NDEF message is only made available for NDEF push when the
     * specified activity(s) are in resumed (foreground) state. The recommended
     * approach is to call this method during your Activity's
     * {@link Activity#onCreate} - see sample
     * code below. This method does not immediately perform any I/O or blocking work,
     * so is safe to call on your main thread.
     *
     * <p>Only one NDEF message can be pushed by the currently resumed activity.
     * If both {@link #setNdefPushMessage} and
     * {@link #setNdefPushMessageCallback} are set, then
     * the callback will take priority.
     *
     * <p>If neither {@link #setNdefPushMessage} or
     * {@link #setNdefPushMessageCallback} have been called for your activity, then
     * the Android OS may choose to send a default NDEF message on your behalf,
     * such as a URI for your application.
     *
     * <p>If {@link #setNdefPushMessage} is called with a null NDEF message,
     * and/or {@link #setNdefPushMessageCallback} is called with a null callback,
     * then NDEF push will be completely disabled for the specified activity(s).
     * This also disables any default NDEF message the Android OS would have
     * otherwise sent on your behalf for those activity(s).
     *
     * <p>If you want to prevent the Android OS from sending default NDEF
     * messages completely (for all activities), you can include a
     * {@code <meta-data>} element inside the {@code <application>}
     * element of your AndroidManifest.xml file, like this:
     * <pre>
     * &lt;application ...>
     *     &lt;meta-data android:name="android.nfc.disable_beam_default"
     *         android:value="true" />
     * &lt;/application></pre>
     *
     * <p>The API allows for multiple activities to be specified at a time,
     * but it is strongly recommended to just register one at a time,
     * and to do so during the activity's {@link Activity#onCreate}. For example:
     * <pre>
     * protected void onCreate(Bundle savedInstanceState) {
     *     super.onCreate(savedInstanceState);
     *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     *     if (nfcAdapter == null) return;  // NFC not available on this device
     *     nfcAdapter.setNdefPushMessage(ndefMessage, this);
     * }</pre>
     * And that is it. Only one call per activity is necessary. The Android
     * OS will automatically release its references to the NDEF message and the
     * Activity object when it is destroyed if you follow this pattern.
     *
     * <p>If your Activity wants to dynamically generate an NDEF message,
     * then set a callback using {@link #setNdefPushMessageCallback} instead
     * of a static message.
     *
     * <p class="note">Do not pass in an Activity that has already been through
     * {@link Activity#onDestroy}. This is guaranteed if you call this API
     * during {@link Activity#onCreate}.
     *
     * <p class="note">For sending large content such as pictures and songs,
     * consider using {@link #setBeamPushUris}, which switches to alternate transports
     * such as Bluetooth to achieve a fast transfer rate.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param message NDEF message to push over NFC, or null to disable
     * @param activity activity for which the NDEF message will be pushed
     * @param activities optional additional activities, however we strongly recommend
     *        to only register one at a time, and to do so in that activity's
     *        {@link Activity#onCreate}
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void setNdefPushMessage(NdefMessage message, Activity activity,
            Activity ... activities) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        int targetSdkVersion = getSdkVersion();
        try {
            if (activity == null) {
                throw new NullPointerException("activity cannot be null");
            }
            mNfcActivityManager.setNdefPushMessage(activity, message, 0);
            for (Activity a : activities) {
                if (a == null) {
                    throw new NullPointerException("activities cannot contain null");
                }
                mNfcActivityManager.setNdefPushMessage(a, message, 0);
            }
        } catch (IllegalStateException e) {
            if (targetSdkVersion < android.os.Build.VERSION_CODES.JELLY_BEAN) {
                // Less strict on old applications - just log the error
                Log.e(TAG, "Cannot call API with Activity that has already " +
                        "been destroyed", e);
            } else {
                // Prevent new applications from making this mistake, re-throw
                throw(e);
            }
        }
    }

    
@hide
/**
     * @hide
     */
    @SystemApi
    public void setNdefPushMessage(NdefMessage message, Activity activity, int flags) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        if (activity == null) {
            throw new NullPointerException("activity cannot be null");
        }
        mNfcActivityManager.setNdefPushMessage(activity, message, flags);
    }

    
Set a callback that dynamically generates NDEF messages to send using Android Beam (TM).

This method may be called at any time before Activity.onDestroy, but the NDEF message callback can only occur when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's Activity.onCreate - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread. 
Only one NDEF message can be pushed by the currently resumed activity. If both setNdefPushMessage and setNdefPushMessageCallback are set, then the callback will take priority. 
If neither setNdefPushMessage or setNdefPushMessageCallback have been called for your activity, then the Android OS may choose to send a default NDEF message on your behalf, such as a URI for your application. 
If setNdefPushMessage is called with a null NDEF message, and/or setNdefPushMessageCallback is called with a null callback, then NDEF push will be completely disabled for the specified activity(s). This also disables any default NDEF message the Android OS would have otherwise sent on your behalf for those activity(s). 
If you want to prevent the Android OS from sending default NDEF messages completely (for all activities), you can include a <meta-data> element inside the <application> element of your AndroidManifest.xml file, like this: 
<application ...>
    <meta-data android:name="android.nfc.disable_beam_default"
        android:value="true" />
</application>


The API allows for multiple activities to be specified at a time, but it is strongly recommended to just register one at a time, and to do so during the activity's Activity.onCreate. For example: 
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
    if (nfcAdapter == null) return;  // NFC not available on this device
    nfcAdapter.setNdefPushMessageCallback(callback, this);
}

And that is it. Only one call per activity is necessary. The Android
OS will automatically release its references to the callback and the
Activity object when it is destroyed if you follow this pattern.

Do not pass in an Activity that has already been through Activity.onDestroy. This is guaranteed if you call this API during Activity.onCreate. 
For sending large content such as pictures and songs, consider using setBeamPushUris, which switches to alternate transports such as Bluetooth to achieve a fast transfer rate. 
Requires the NFC.NFC permission. 
Params:
  • callback – callback, or null to disable
  • activity – activity for which the NDEF message will be pushed
  • activities – optional additional activities, however we strongly recommend to only register one at a time, and to do so in that activity's Activity.onCreate
Throws:
/**
     * Set a callback that dynamically generates NDEF messages to send using Android Beam (TM).
     *
     * <p>This method may be called at any time before {@link Activity#onDestroy},
     * but the NDEF message callback can only occur when the
     * specified activity(s) are in resumed (foreground) state. The recommended
     * approach is to call this method during your Activity's
     * {@link Activity#onCreate} - see sample
     * code below. This method does not immediately perform any I/O or blocking work,
     * so is safe to call on your main thread.
     *
     * <p>Only one NDEF message can be pushed by the currently resumed activity.
     * If both {@link #setNdefPushMessage} and
     * {@link #setNdefPushMessageCallback} are set, then
     * the callback will take priority.
     *
     * <p>If neither {@link #setNdefPushMessage} or
     * {@link #setNdefPushMessageCallback} have been called for your activity, then
     * the Android OS may choose to send a default NDEF message on your behalf,
     * such as a URI for your application.
     *
     * <p>If {@link #setNdefPushMessage} is called with a null NDEF message,
     * and/or {@link #setNdefPushMessageCallback} is called with a null callback,
     * then NDEF push will be completely disabled for the specified activity(s).
     * This also disables any default NDEF message the Android OS would have
     * otherwise sent on your behalf for those activity(s).
     *
     * <p>If you want to prevent the Android OS from sending default NDEF
     * messages completely (for all activities), you can include a
     * {@code <meta-data>} element inside the {@code <application>}
     * element of your AndroidManifest.xml file, like this:
     * <pre>
     * &lt;application ...>
     *     &lt;meta-data android:name="android.nfc.disable_beam_default"
     *         android:value="true" />
     * &lt;/application></pre>
     *
     * <p>The API allows for multiple activities to be specified at a time,
     * but it is strongly recommended to just register one at a time,
     * and to do so during the activity's {@link Activity#onCreate}. For example:
     * <pre>
     * protected void onCreate(Bundle savedInstanceState) {
     *     super.onCreate(savedInstanceState);
     *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     *     if (nfcAdapter == null) return;  // NFC not available on this device
     *     nfcAdapter.setNdefPushMessageCallback(callback, this);
     * }</pre>
     * And that is it. Only one call per activity is necessary. The Android
     * OS will automatically release its references to the callback and the
     * Activity object when it is destroyed if you follow this pattern.
     *
     * <p class="note">Do not pass in an Activity that has already been through
     * {@link Activity#onDestroy}. This is guaranteed if you call this API
     * during {@link Activity#onCreate}.
     * <p class="note">For sending large content such as pictures and songs,
     * consider using {@link #setBeamPushUris}, which switches to alternate transports
     * such as Bluetooth to achieve a fast transfer rate.
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param callback callback, or null to disable
     * @param activity activity for which the NDEF message will be pushed
     * @param activities optional additional activities, however we strongly recommend
     *        to only register one at a time, and to do so in that activity's
     *        {@link Activity#onCreate}
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void setNdefPushMessageCallback(CreateNdefMessageCallback callback, Activity activity,
            Activity ... activities) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        int targetSdkVersion = getSdkVersion();
        try {
            if (activity == null) {
                throw new NullPointerException("activity cannot be null");
            }
            mNfcActivityManager.setNdefPushMessageCallback(activity, callback, 0);
            for (Activity a : activities) {
                if (a == null) {
                    throw new NullPointerException("activities cannot contain null");
                }
                mNfcActivityManager.setNdefPushMessageCallback(a, callback, 0);
            }
        } catch (IllegalStateException e) {
            if (targetSdkVersion < android.os.Build.VERSION_CODES.JELLY_BEAN) {
                // Less strict on old applications - just log the error
                Log.e(TAG, "Cannot call API with Activity that has already " +
                        "been destroyed", e);
            } else {
                // Prevent new applications from making this mistake, re-throw
                throw(e);
            }
        }
    }

    
@hide
/**
     * @hide
     */
    public void setNdefPushMessageCallback(CreateNdefMessageCallback callback, Activity activity,
            int flags) {
        if (activity == null) {
            throw new NullPointerException("activity cannot be null");
        }
        mNfcActivityManager.setNdefPushMessageCallback(activity, callback, flags);
    }

    
Set a callback on successful Android Beam (TM).

This method may be called at any time before Activity.onDestroy, but the callback can only occur when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's Activity.onCreate - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread. 
The API allows for multiple activities to be specified at a time, but it is strongly recommended to just register one at a time, and to do so during the activity's Activity.onCreate. For example: 
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
    if (nfcAdapter == null) return;  // NFC not available on this device
    nfcAdapter.setOnNdefPushCompleteCallback(callback, this);
}

And that is it. Only one call per activity is necessary. The Android
OS will automatically release its references to the callback and the
Activity object when it is destroyed if you follow this pattern.

Do not pass in an Activity that has already been through Activity.onDestroy. This is guaranteed if you call this API during Activity.onCreate. 
Requires the NFC.NFC permission. 
Params:
  • callback – callback, or null to disable
  • activity – activity for which the NDEF message will be pushed
  • activities – optional additional activities, however we strongly recommend to only register one at a time, and to do so in that activity's Activity.onCreate
Throws:
/**
     * Set a callback on successful Android Beam (TM).
     *
     * <p>This method may be called at any time before {@link Activity#onDestroy},
     * but the callback can only occur when the
     * specified activity(s) are in resumed (foreground) state. The recommended
     * approach is to call this method during your Activity's
     * {@link Activity#onCreate} - see sample
     * code below. This method does not immediately perform any I/O or blocking work,
     * so is safe to call on your main thread.
     *
     * <p>The API allows for multiple activities to be specified at a time,
     * but it is strongly recommended to just register one at a time,
     * and to do so during the activity's {@link Activity#onCreate}. For example:
     * <pre>
     * protected void onCreate(Bundle savedInstanceState) {
     *     super.onCreate(savedInstanceState);
     *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     *     if (nfcAdapter == null) return;  // NFC not available on this device
     *     nfcAdapter.setOnNdefPushCompleteCallback(callback, this);
     * }</pre>
     * And that is it. Only one call per activity is necessary. The Android
     * OS will automatically release its references to the callback and the
     * Activity object when it is destroyed if you follow this pattern.
     *
     * <p class="note">Do not pass in an Activity that has already been through
     * {@link Activity#onDestroy}. This is guaranteed if you call this API
     * during {@link Activity#onCreate}.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param callback callback, or null to disable
     * @param activity activity for which the NDEF message will be pushed
     * @param activities optional additional activities, however we strongly recommend
     *        to only register one at a time, and to do so in that activity's
     *        {@link Activity#onCreate}
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void setOnNdefPushCompleteCallback(OnNdefPushCompleteCallback callback,
            Activity activity, Activity ... activities) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        int targetSdkVersion = getSdkVersion();
        try {
            if (activity == null) {
                throw new NullPointerException("activity cannot be null");
            }
            mNfcActivityManager.setOnNdefPushCompleteCallback(activity, callback);
            for (Activity a : activities) {
                if (a == null) {
                    throw new NullPointerException("activities cannot contain null");
                }
                mNfcActivityManager.setOnNdefPushCompleteCallback(a, callback);
            }
        } catch (IllegalStateException e) {
            if (targetSdkVersion < android.os.Build.VERSION_CODES.JELLY_BEAN) {
                // Less strict on old applications - just log the error
                Log.e(TAG, "Cannot call API with Activity that has already " +
                        "been destroyed", e);
            } else {
                // Prevent new applications from making this mistake, re-throw
                throw(e);
            }
        }
    }

    
Enable foreground dispatch to the given Activity.

This will give give priority to the foreground activity when dispatching a discovered Tag to an application. 
If any IntentFilters are provided to this method they are used to match dispatch Intents for both the ACTION_NDEF_DISCOVERED and ACTION_TAG_DISCOVERED. Since ACTION_TECH_DISCOVERED relies on meta data outside of the IntentFilter matching for that dispatch Intent is handled by passing in the tech lists separately. Each first level entry in the tech list represents an array of technologies that must all be present to match. If any of the first level sets match then the dispatch is routed through the given PendingIntent. In other words, the second level is ANDed together and the first level entries are ORed together. 
If you pass null for both the filters and techLists parameters that acts a wild card and will cause the foreground activity to receive all tags via the ACTION_TAG_DISCOVERED intent. 
This method must be called from the main thread, and only when the activity is in the foreground (resumed). Also, activities must call disableForegroundDispatch before the completion of their Activity.onPause callback to disable foreground dispatch after it has been enabled. 
Requires the NFC.NFC permission. 
Params:
  • activity – the Activity to dispatch to
  • intent – the PendingIntent to start for the dispatch
  • filters – the IntentFilters to override dispatching for, or null to always dispatch
  • techLists – the tech lists used to perform matching for dispatching of the ACTION_TECH_DISCOVERED intent
Throws:
/**
     * Enable foreground dispatch to the given Activity.
     *
     * <p>This will give give priority to the foreground activity when
     * dispatching a discovered {@link Tag} to an application.
     *
     * <p>If any IntentFilters are provided to this method they are used to match dispatch Intents
     * for both the {@link NfcAdapter#ACTION_NDEF_DISCOVERED} and
     * {@link NfcAdapter#ACTION_TAG_DISCOVERED}. Since {@link NfcAdapter#ACTION_TECH_DISCOVERED}
     * relies on meta data outside of the IntentFilter matching for that dispatch Intent is handled
     * by passing in the tech lists separately. Each first level entry in the tech list represents
     * an array of technologies that must all be present to match. If any of the first level sets
     * match then the dispatch is routed through the given PendingIntent. In other words, the second
     * level is ANDed together and the first level entries are ORed together.
     *
     * <p>If you pass {@code null} for both the {@code filters} and {@code techLists} parameters
     * that acts a wild card and will cause the foreground activity to receive all tags via the
     * {@link NfcAdapter#ACTION_TAG_DISCOVERED} intent.
     *
     * <p>This method must be called from the main thread, and only when the activity is in the
     * foreground (resumed). Also, activities must call {@link #disableForegroundDispatch} before
     * the completion of their {@link Activity#onPause} callback to disable foreground dispatch
     * after it has been enabled.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param activity the Activity to dispatch to
     * @param intent the PendingIntent to start for the dispatch
     * @param filters the IntentFilters to override dispatching for, or null to always dispatch
     * @param techLists the tech lists used to perform matching for dispatching of the
     *      {@link NfcAdapter#ACTION_TECH_DISCOVERED} intent
     * @throws IllegalStateException if the Activity is not currently in the foreground
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void enableForegroundDispatch(Activity activity, PendingIntent intent,
            IntentFilter[] filters, String[][] techLists) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        if (activity == null || intent == null) {
            throw new NullPointerException();
        }
        if (!activity.isResumed()) {
            throw new IllegalStateException("Foreground dispatch can only be enabled " +
                    "when your activity is resumed");
        }
        try {
            TechListParcel parcel = null;
            if (techLists != null && techLists.length > 0) {
                parcel = new TechListParcel(techLists);
            }
            ActivityThread.currentActivityThread().registerOnActivityPausedListener(activity,
                    mForegroundDispatchListener);
            sService.setForegroundDispatch(intent, filters, parcel);
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
        }
    }

    
Disable foreground dispatch to the given activity.

After calling enableForegroundDispatch, an activity must call this method before its Activity.onPause callback completes. 
This method must be called from the main thread.

Requires the NFC.NFC permission. 
Params:
  • activity – the Activity to disable dispatch to
Throws:
/**
     * Disable foreground dispatch to the given activity.
     *
     * <p>After calling {@link #enableForegroundDispatch}, an activity
     * must call this method before its {@link Activity#onPause} callback
     * completes.
     *
     * <p>This method must be called from the main thread.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param activity the Activity to disable dispatch to
     * @throws IllegalStateException if the Activity has already been paused
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void disableForegroundDispatch(Activity activity) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        ActivityThread.currentActivityThread().unregisterOnActivityPausedListener(activity,
                mForegroundDispatchListener);
        disableForegroundDispatchInternal(activity, false);
    }

    OnActivityPausedListener mForegroundDispatchListener = new OnActivityPausedListener() {
        @Override
        public void onPaused(Activity activity) {
            disableForegroundDispatchInternal(activity, true);
        }
    };

    void disableForegroundDispatchInternal(Activity activity, boolean force) {
        try {
            sService.setForegroundDispatch(null, null, null);
            if (!force && !activity.isResumed()) {
                throw new IllegalStateException("You must disable foreground dispatching " +
                        "while your activity is still resumed");
            }
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
        }
    }

    
Limit the NFC controller to reader mode while this Activity is in the foreground.

In this mode the NFC controller will only act as an NFC tag reader/writer,
thus disabling any peer-to-peer (Android Beam) and card-emulation modes of
the NFC adapter on this device.

Use FLAG_READER_SKIP_NDEF_CHECK to prevent the platform from performing any NDEF checks in reader mode. Note that this will prevent the Ndef tag technology from being enumerated on the tag, and that NDEF-based tag dispatch will not be functional. 
For interacting with tags that are emulated on another Android device using Android's host-based card-emulation, the recommended flags are FLAG_READER_NFC_A and FLAG_READER_SKIP_NDEF_CHECK. 
Params:
  • activity – the Activity that requests the adapter to be in reader mode
  • callback – the callback to be called when a tag is discovered
  • flags – Flags indicating poll technologies and other optional parameters
  • extras – Additional extras for configuring reader mode.
Throws:
/**
     * Limit the NFC controller to reader mode while this Activity is in the foreground.
     *
     * <p>In this mode the NFC controller will only act as an NFC tag reader/writer,
     * thus disabling any peer-to-peer (Android Beam) and card-emulation modes of
     * the NFC adapter on this device.
     *
     * <p>Use {@link #FLAG_READER_SKIP_NDEF_CHECK} to prevent the platform from
     * performing any NDEF checks in reader mode. Note that this will prevent the
     * {@link Ndef} tag technology from being enumerated on the tag, and that
     * NDEF-based tag dispatch will not be functional.
     *
     * <p>For interacting with tags that are emulated on another Android device
     * using Android's host-based card-emulation, the recommended flags are
     * {@link #FLAG_READER_NFC_A} and {@link #FLAG_READER_SKIP_NDEF_CHECK}.
     *
     * @param activity the Activity that requests the adapter to be in reader mode
     * @param callback the callback to be called when a tag is discovered
     * @param flags Flags indicating poll technologies and other optional parameters
     * @param extras Additional extras for configuring reader mode.
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void enableReaderMode(Activity activity, ReaderCallback callback, int flags,
            Bundle extras) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        mNfcActivityManager.enableReaderMode(activity, callback, flags, extras);
    }

    
Restore the NFC adapter to normal mode of operation: supporting
peer-to-peer (Android Beam), card emulation, and polling for
all supported tag technologies.

Params:
  • activity – the Activity that currently has reader mode enabled
Throws:
/**
     * Restore the NFC adapter to normal mode of operation: supporting
     * peer-to-peer (Android Beam), card emulation, and polling for
     * all supported tag technologies.
     *
     * @param activity the Activity that currently has reader mode enabled
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public void disableReaderMode(Activity activity) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        mNfcActivityManager.disableReaderMode(activity);
    }

    
Manually invoke Android Beam to share data.

The Android Beam animation is normally only shown when two NFC-capable
devices come into range.
By calling this method, an Activity can invoke the Beam animation directly
even if no other NFC device is in range yet. The Beam animation will then
prompt the user to tap another NFC-capable device to complete the data
transfer.

The main advantage of using this method is that it avoids the need for the
user to tap the screen to complete the transfer, as this method already
establishes the direction of the transfer and the consent of the user to
share data. Callers are responsible for making sure that the user has
consented to sharing data on NFC tap.

Note that to use this method, the passed in Activity must have already set data to share over Beam by using method calls such as setNdefPushMessageCallback or setBeamPushUrisCallback. 
Params:
  • activity – the current foreground Activity that has registered data to share
Throws:
Returns:whether the Beam animation was successfully invoked
/**
     * Manually invoke Android Beam to share data.
     *
     * <p>The Android Beam animation is normally only shown when two NFC-capable
     * devices come into range.
     * By calling this method, an Activity can invoke the Beam animation directly
     * even if no other NFC device is in range yet. The Beam animation will then
     * prompt the user to tap another NFC-capable device to complete the data
     * transfer.
     *
     * <p>The main advantage of using this method is that it avoids the need for the
     * user to tap the screen to complete the transfer, as this method already
     * establishes the direction of the transfer and the consent of the user to
     * share data. Callers are responsible for making sure that the user has
     * consented to sharing data on NFC tap.
     *
     * <p>Note that to use this method, the passed in Activity must have already
     * set data to share over Beam by using method calls such as
     * {@link #setNdefPushMessageCallback} or
     * {@link #setBeamPushUrisCallback}.
     *
     * @param activity the current foreground Activity that has registered data to share
     * @return whether the Beam animation was successfully invoked
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public boolean invokeBeam(Activity activity) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        if (activity == null) {
            throw new NullPointerException("activity may not be null.");
        }
        enforceResumed(activity);
        try {
            sService.invokeBeam();
            return true;
        } catch (RemoteException e) {
            Log.e(TAG, "invokeBeam: NFC process has died.");
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
@hide
/**
     * @hide
     */
    public boolean invokeBeam(BeamShareData shareData) {
        try {
            Log.e(TAG, "invokeBeamInternal()");
            sService.invokeBeamInternal(shareData);
            return true;
        } catch (RemoteException e) {
            Log.e(TAG, "invokeBeam: NFC process has died.");
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Enable NDEF message push over NFC while this Activity is in the foreground.

You must explicitly call this method every time the activity is resumed, and you must call disableForegroundNdefPush before your activity completes Activity.onPause. 
Strongly recommend to use the new setNdefPushMessage instead: it automatically hooks into your activity life-cycle, so you do not need to call enable/disable in your onResume/onPause. 
For NDEF push to function properly the other NFC device must
support either NFC Forum's SNEP (Simple Ndef Exchange Protocol), or
Android's "com.android.npp" (Ndef Push Protocol). This was optional
on Gingerbread level Android NFC devices, but SNEP is mandatory on
Ice-Cream-Sandwich and beyond.

This method must be called from the main thread.

Requires the NFC.NFC permission. 
Params:
  • activity – foreground activity
  • message – a NDEF Message to push over NFC
Throws:
Deprecated:use setNdefPushMessage instead
/**
     * Enable NDEF message push over NFC while this Activity is in the foreground.
     *
     * <p>You must explicitly call this method every time the activity is
     * resumed, and you must call {@link #disableForegroundNdefPush} before
     * your activity completes {@link Activity#onPause}.
     *
     * <p>Strongly recommend to use the new {@link #setNdefPushMessage}
     * instead: it automatically hooks into your activity life-cycle,
     * so you do not need to call enable/disable in your onResume/onPause.
     *
     * <p>For NDEF push to function properly the other NFC device must
     * support either NFC Forum's SNEP (Simple Ndef Exchange Protocol), or
     * Android's "com.android.npp" (Ndef Push Protocol). This was optional
     * on Gingerbread level Android NFC devices, but SNEP is mandatory on
     * Ice-Cream-Sandwich and beyond.
     *
     * <p>This method must be called from the main thread.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param activity foreground activity
     * @param message a NDEF Message to push over NFC
     * @throws IllegalStateException if the activity is not currently in the foreground
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     * @deprecated use {@link #setNdefPushMessage} instead
     */
    @Deprecated
    public void enableForegroundNdefPush(Activity activity, NdefMessage message) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        if (activity == null || message == null) {
            throw new NullPointerException();
        }
        enforceResumed(activity);
        mNfcActivityManager.setNdefPushMessage(activity, message, 0);
    }

    
Disable NDEF message push over P2P.

After calling enableForegroundNdefPush, an activity must call this method before its Activity.onPause callback completes. 
Strongly recommend to use the new setNdefPushMessage instead: it automatically hooks into your activity life-cycle, so you do not need to call enable/disable in your onResume/onPause. 
This method must be called from the main thread.

Requires the NFC.NFC permission. 
Params:
  • activity – the Foreground activity
Throws:
Deprecated:use setNdefPushMessage instead
/**
     * Disable NDEF message push over P2P.
     *
     * <p>After calling {@link #enableForegroundNdefPush}, an activity
     * must call this method before its {@link Activity#onPause} callback
     * completes.
     *
     * <p>Strongly recommend to use the new {@link #setNdefPushMessage}
     * instead: it automatically hooks into your activity life-cycle,
     * so you do not need to call enable/disable in your onResume/onPause.
     *
     * <p>This method must be called from the main thread.
     *
     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
     *
     * @param activity the Foreground activity
     * @throws IllegalStateException if the Activity has already been paused
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     * @deprecated use {@link #setNdefPushMessage} instead
     */
    @Deprecated
    public void disableForegroundNdefPush(Activity activity) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        if (activity == null) {
            throw new NullPointerException();
        }
        enforceResumed(activity);
        mNfcActivityManager.setNdefPushMessage(activity, null, 0);
        mNfcActivityManager.setNdefPushMessageCallback(activity, null, 0);
        mNfcActivityManager.setOnNdefPushCompleteCallback(activity, null);
    }

    
Enable NDEF Push feature.

This API is for the Settings application.

@hide
/**
     * Enable NDEF Push feature.
     * <p>This API is for the Settings application.
     * @hide
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
    public boolean enableNdefPush() {
        if (!sHasNfcFeature) {
            throw new UnsupportedOperationException();
        }
        try {
            return sService.enableNdefPush();
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Disable NDEF Push feature.

This API is for the Settings application.

@hide
/**
     * Disable NDEF Push feature.
     * <p>This API is for the Settings application.
     * @hide
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
    public boolean disableNdefPush() {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        try {
            return sService.disableNdefPush();
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Return true if the NDEF Push (Android Beam) feature is enabled.

This function will return true only if both NFC is enabled, and the
NDEF Push feature is enabled.

Note that if NFC is enabled but NDEF Push is disabled then this
device can still receive NDEF messages, it just cannot send them.

Applications cannot directly toggle the NDEF Push feature, but they
can request Settings UI allowing the user to toggle NDEF Push using
startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS))

Example usage in an Activity that requires NDEF Push:

protected void onResume() {
    super.onResume();
    if (!nfcAdapter.isEnabled()) {
        startActivity(new Intent(Settings.ACTION_NFC_SETTINGS));
    } else if (!nfcAdapter.isNdefPushEnabled()) {
        startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS));
    }
}


Throws:
See Also:
  • ACTION_NFCSHARING_SETTINGS.ACTION_NFCSHARING_SETTINGS
Returns:true if NDEF Push feature is enabled
/**
     * Return true if the NDEF Push (Android Beam) feature is enabled.
     * <p>This function will return true only if both NFC is enabled, and the
     * NDEF Push feature is enabled.
     * <p>Note that if NFC is enabled but NDEF Push is disabled then this
     * device can still <i>receive</i> NDEF messages, it just cannot send them.
     * <p>Applications cannot directly toggle the NDEF Push feature, but they
     * can request Settings UI allowing the user to toggle NDEF Push using
     * <code>startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS))</code>
     * <p>Example usage in an Activity that requires NDEF Push:
     * <p><pre>
     * protected void onResume() {
     *     super.onResume();
     *     if (!nfcAdapter.isEnabled()) {
     *         startActivity(new Intent(Settings.ACTION_NFC_SETTINGS));
     *     } else if (!nfcAdapter.isNdefPushEnabled()) {
     *         startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS));
     *     }
     * }</pre>
     *
     * @see android.provider.Settings#ACTION_NFCSHARING_SETTINGS
     * @return true if NDEF Push feature is enabled
     * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
     */
    public boolean isNdefPushEnabled() {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        try {
            return sService.isNdefPushEnabled();
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
Signals that you are no longer interested in communicating with an NFC tag for as long as it remains in range. All future attempted communication to this tag will fail with IOException. The NFC controller will be put in a low-power polling mode, allowing the device to save power in cases where it's "attached" to a tag all the time (e.g. a tag in car dock). Additionally the debounceMs parameter allows you to specify for how long the tag needs to have gone out of range, before it will be dispatched again. Note: the NFC controller typically polls at a pretty slow interval (100 - 500 ms). This means that if the tag repeatedly goes in and out of range (for example, in case of a flaky connection), and the controller happens to poll every time the tag is out of range, it *will* re-dispatch the tag after debounceMs, despite the tag having been "in range" during the interval. Note 2: if a tag with another UID is detected after this API is called, its effect will be cancelled; if this tag shows up before the amount of time specified in debounceMs, it will be dispatched again. Note 3: some tags have a random UID, in which case this API won't work reliably. 
Params:
  • tag –  the Tag to ignore.
  • debounceMs – minimum amount of time the tag needs to be out of range before being
                  dispatched again.
  • tagRemovedListener – listener to be called when the tag is removed from the field.
                          Note that this will only be called if the tag has been out of range
                          for at least debounceMs, or if another tag came into range before
                          debounceMs. May be null in case you don't want a callback.
  • handler – the Handler that will be used for delivering the callback. if the handler is null, then the thread used for delivering the callback is unspecified.
Returns:false if the tag couldn't be found (or has already gone out of range), true otherwise
/**
     * Signals that you are no longer interested in communicating with an NFC tag
     * for as long as it remains in range.
     *
     * All future attempted communication to this tag will fail with {@link IOException}.
     * The NFC controller will be put in a low-power polling mode, allowing the device
     * to save power in cases where it's "attached" to a tag all the time (e.g. a tag in
     * car dock).
     *
     * Additionally the debounceMs parameter allows you to specify for how long the tag needs
     * to have gone out of range, before it will be dispatched again.
     *
     * Note: the NFC controller typically polls at a pretty slow interval (100 - 500 ms).
     * This means that if the tag repeatedly goes in and out of range (for example, in
     * case of a flaky connection), and the controller happens to poll every time the
     * tag is out of range, it *will* re-dispatch the tag after debounceMs, despite the tag
     * having been "in range" during the interval.
     *
     * Note 2: if a tag with another UID is detected after this API is called, its effect
     * will be cancelled; if this tag shows up before the amount of time specified in
     * debounceMs, it will be dispatched again.
     *
     * Note 3: some tags have a random UID, in which case this API won't work reliably.
     *
     * @param tag        the {@link android.nfc.Tag Tag} to ignore.
     * @param debounceMs minimum amount of time the tag needs to be out of range before being
     *                   dispatched again.
     * @param tagRemovedListener listener to be called when the tag is removed from the field.
     *                           Note that this will only be called if the tag has been out of range
     *                           for at least debounceMs, or if another tag came into range before
     *                           debounceMs. May be null in case you don't want a callback.
     * @param handler the {@link android.os.Handler Handler} that will be used for delivering
     *                the callback. if the handler is null, then the thread used for delivering
     *                the callback is unspecified.
     * @return false if the tag couldn't be found (or has already gone out of range), true otherwise
     */
    public boolean ignore(final Tag tag, int debounceMs,
                          final OnTagRemovedListener tagRemovedListener, final Handler handler) {
        ITagRemovedCallback.Stub iListener = null;
        if (tagRemovedListener != null) {
            iListener = new ITagRemovedCallback.Stub() {
                @Override
                public void onTagRemoved() throws RemoteException {
                    if (handler != null) {
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                tagRemovedListener.onTagRemoved();
                            }
                        });
                    } else {
                        tagRemovedListener.onTagRemoved();
                    }
                    synchronized (mLock) {
                        mTagRemovedListener = null;
                    }
                }
            };
        }
        synchronized (mLock) {
            mTagRemovedListener = iListener;
        }
        try {
            return sService.ignore(tag.getServiceHandle(), debounceMs, iListener);
        } catch (RemoteException e) {
            return false;
        }
    }

    
Inject a mock NFC tag.

Used for testing purposes.

Requires the WRITE_SECURE_SETTINGS.WRITE_SECURE_SETTINGS permission. 
@hide
/**
     * Inject a mock NFC tag.<p>
     * Used for testing purposes.
     * <p class="note">Requires the
     * {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission.
     * @hide
     */
    public void dispatch(Tag tag) {
        if (tag == null) {
            throw new NullPointerException("tag cannot be null");
        }
        try {
            sService.dispatch(tag);
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
        }
    }

    
@hide
/**
     * @hide
     */
    public void setP2pModes(int initiatorModes, int targetModes) {
        try {
            sService.setP2pModes(initiatorModes, targetModes);
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
        }
    }

    
Registers a new NFC unlock handler with the NFC service.

NFC unlock handlers are intended to unlock the keyguard in the presence of a trusted
NFC device. The handler should return true if it successfully authenticates the user and
unlocks the keyguard.

 The parameter tagTechnologies determines which Tag technologies will be polled for at the lockscreen. Polling for less tag technologies reduces latency, and so it is strongly recommended to only provide the Tag technologies that the handler is expected to receive. There must be at least one tag technology provided, otherwise the unlock handler is ignored. 
@hide
/**
     * Registers a new NFC unlock handler with the NFC service.
     *
     * <p />NFC unlock handlers are intended to unlock the keyguard in the presence of a trusted
     * NFC device. The handler should return true if it successfully authenticates the user and
     * unlocks the keyguard.
     *
     * <p /> The parameter {@code tagTechnologies} determines which Tag technologies will be polled for
     * at the lockscreen. Polling for less tag technologies reduces latency, and so it is
     * strongly recommended to only provide the Tag technologies that the handler is expected to
     * receive. There must be at least one tag technology provided, otherwise the unlock handler
     * is ignored.
     *
     * @hide
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
    public boolean addNfcUnlockHandler(final NfcUnlockHandler unlockHandler,
                                       String[] tagTechnologies) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        // If there are no tag technologies, don't bother adding unlock handler
        if (tagTechnologies.length == 0) {
            return false;
        }

        try {
            synchronized (mLock) {
                if (mNfcUnlockHandlers.containsKey(unlockHandler)) {
                    // update the tag technologies
                    sService.removeNfcUnlockHandler(mNfcUnlockHandlers.get(unlockHandler));
                    mNfcUnlockHandlers.remove(unlockHandler);
                }

                INfcUnlockHandler.Stub iHandler = new INfcUnlockHandler.Stub() {
                    @Override
                    public boolean onUnlockAttempted(Tag tag) throws RemoteException {
                        return unlockHandler.onUnlockAttempted(tag);
                    }
                };

                sService.addNfcUnlockHandler(iHandler,
                        Tag.getTechCodesFromStrings(tagTechnologies));
                mNfcUnlockHandlers.put(unlockHandler, iHandler);
            }
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        } catch (IllegalArgumentException e) {
            Log.e(TAG, "Unable to register LockscreenDispatch", e);
            return false;
        }

        return true;
    }

    
Removes a previously registered unlock handler. Also removes the tag technologies
associated with the removed unlock handler.

@hide
/**
     * Removes a previously registered unlock handler. Also removes the tag technologies
     * associated with the removed unlock handler.
     *
     * @hide
     */
    @SystemApi
    @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
    public boolean removeNfcUnlockHandler(NfcUnlockHandler unlockHandler) {
        synchronized (NfcAdapter.class) {
            if (!sHasNfcFeature) {
                throw new UnsupportedOperationException();
            }
        }
        try {
            synchronized (mLock) {
                if (mNfcUnlockHandlers.containsKey(unlockHandler)) {
                    sService.removeNfcUnlockHandler(mNfcUnlockHandlers.remove(unlockHandler));
                }

                return true;
            }
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return false;
        }
    }

    
@hide
/**
     * @hide
     */
    public INfcAdapterExtras getNfcAdapterExtrasInterface() {
        if (mContext == null) {
            throw new UnsupportedOperationException("You need a context on NfcAdapter to use the "
                    + " NFC extras APIs");
        }
        try {
            return sService.getNfcAdapterExtrasInterface(mContext.getPackageName());
        } catch (RemoteException e) {
            attemptDeadServiceRecovery(e);
            return null;
        }
    }

    void enforceResumed(Activity activity) {
        if (!activity.isResumed()) {
            throw new IllegalStateException("API cannot be called while activity is paused");
        }
    }

    int getSdkVersion() {
        if (mContext == null) {
            return android.os.Build.VERSION_CODES.GINGERBREAD; // best guess
        } else {
            return mContext.getApplicationInfo().targetSdkVersion;
        }
    }
}