https://source.android.com/ 
/*
 * Copyright (C) 2011 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 com.android.future.usb;

import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.hardware.usb.IUsbManager;
import android.os.IBinder;
import android.os.ParcelFileDescriptor;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.util.Log;


This is a wrapper class for the USB Manager to support USB accessories.

You can obtain an instance of this class by calling getInstance 
/**
 * This is a wrapper class for the USB Manager to support USB accessories.
 *
 * <p>You can obtain an instance of this class by calling {@link #getInstance}
 *
 */
public class UsbManager {
    private static final String TAG = "UsbManager";

   
Broadcast Action: A broadcast for USB accessory attached event. This intent is sent when a USB accessory is attached. Call getAccessory(Intent) to retrieve the UsbAccessory for the attached accessory. 
/**
     * Broadcast Action:  A broadcast for USB accessory attached event.
     *
     * This intent is sent when a USB accessory is attached.
     * Call {@link #getAccessory(android.content.Intent)} to retrieve the
     * {@link com.google.android.usb.UsbAccessory} for the attached accessory.
     */
    public static final String ACTION_USB_ACCESSORY_ATTACHED =
            "android.hardware.usb.action.USB_ACCESSORY_ATTACHED";

   
Broadcast Action: A broadcast for USB accessory detached event. This intent is sent when a USB accessory is detached. Call getAccessory(Intent) to retrieve the UsbAccessory for the attached accessory that was detached. 
/**
     * Broadcast Action:  A broadcast for USB accessory detached event.
     *
     * This intent is sent when a USB accessory is detached.
     * Call {@link #getAccessory(android.content.Intent)} to retrieve the
     * {@link com.google.android.usb.UsbAccessory} for the attached accessory that was detached.
     */
    public static final String ACTION_USB_ACCESSORY_DETACHED =
            "android.hardware.usb.action.USB_ACCESSORY_DETACHED";

    
Name of extra added to the PendingIntent passed into {#requestPermission} or {#requestPermission} containing a boolean value indicating whether the user granted permission or not. 
/**
     * Name of extra added to the {@link android.app.PendingIntent}
     * passed into {#requestPermission} or {#requestPermission}
     * containing a boolean value indicating whether the user granted permission or not.
     */
    public static final String EXTRA_PERMISSION_GRANTED = "permission";

    private final Context mContext;
    private final IUsbManager mService;

    private UsbManager(Context context, IUsbManager service) {
        mContext = context;
        mService = service;
    }

    
Returns a new instance of this class.

Params:
Returns:UsbManager instance.
/**
     * Returns a new instance of this class.
     *
     * @param context the caller's {@link android.content.Context}
     * @return UsbManager instance.
     */
    public static UsbManager getInstance(Context context) {
        IBinder b = ServiceManager.getService(Context.USB_SERVICE);
        return new UsbManager(context, IUsbManager.Stub.asInterface(b));
    }

    
Returns the UsbAccessory for a ACTION_USB_ACCESSORY_ATTACHED or ACTION_USB_ACCESSORY_ATTACHED broadcast Intent. This can also be used to retrieve the accessory from the result of a call to {#requestPermission}. 
Returns:UsbAccessory for the intent.
/**
     * Returns the {@link com.google.android.usb.UsbAccessory} for
     * a {@link #ACTION_USB_ACCESSORY_ATTACHED} or {@link #ACTION_USB_ACCESSORY_ATTACHED}
     * broadcast Intent. This can also be used to retrieve the accessory from the result
     * of a call to {#requestPermission}.
     *
     * @return UsbAccessory for the intent.
     */
    public static UsbAccessory getAccessory(Intent intent) {
        android.hardware.usb.UsbAccessory accessory =
            intent.getParcelableExtra(android.hardware.usb.UsbManager.EXTRA_ACCESSORY);
        if (accessory == null) {
            return null;
        } else {
            return new UsbAccessory(accessory);
        }
    }

    
Returns a list of currently attached USB accessories.
(in the current implementation there can be at most one)

Returns:list of USB accessories, or null if none are attached.
/**
     * Returns a list of currently attached USB accessories.
     * (in the current implementation there can be at most one)
     *
     * @return list of USB accessories, or null if none are attached.
     */
    public UsbAccessory[] getAccessoryList() {
        try {
            android.hardware.usb.UsbAccessory accessory = mService.getCurrentAccessory();
            if (accessory == null) {
                return null;
            } else {
                return new UsbAccessory[] { new UsbAccessory(accessory) };
            }
        } catch (RemoteException e) {
            Log.e(TAG, "RemoteException in getAccessoryList" , e);
            return null;
        }
    }

    
Opens a file descriptor for reading and writing data to the USB accessory.

Params:
  • accessory – the USB accessory to open
Returns:file descriptor, or null if the accessor could not be opened.
/**
     * Opens a file descriptor for reading and writing data to the USB accessory.
     *
     * @param accessory the USB accessory to open
     * @return file descriptor, or null if the accessor could not be opened.
     */
    public ParcelFileDescriptor openAccessory(UsbAccessory accessory) {
        try {
            return mService.openAccessory(new android.hardware.usb.UsbAccessory(
                    accessory.getManufacturer(),accessory.getModel(),
                    accessory.getDescription(), accessory.getVersion(),
                    accessory.getUri(), accessory.getSerial()));
        } catch (RemoteException e) {
            Log.e(TAG, "RemoteException in openAccessory" , e);
            return null;
        }
    }

    
Returns true if the caller has permission to access the accessory. Permission might have been granted temporarily via requestPermission or by the user choosing the caller as the default application for the accessory. 
Params:
  • accessory – to check permissions for
Returns:true if caller has permission
/**
     * Returns true if the caller has permission to access the accessory.
     * Permission might have been granted temporarily via
     * {@link #requestPermission} or
     * by the user choosing the caller as the default application for the accessory.
     *
     * @param accessory to check permissions for
     * @return true if caller has permission
     */
    public boolean hasPermission(UsbAccessory accessory) {
        try {
            return mService.hasAccessoryPermission(new android.hardware.usb.UsbAccessory(
                    accessory.getManufacturer(),accessory.getModel(),
                    accessory.getDescription(), accessory.getVersion(),
                    accessory.getUri(), accessory.getSerial()));
        } catch (RemoteException e) {
            Log.e(TAG, "RemoteException in hasPermission", e);
            return false;
        }
    }

    
Requests temporary permission for the given package to access the accessory. This may result in a system dialog being displayed to the user if permission had not already been granted. Success or failure is returned via the PendingIntent pi. The boolean extra EXTRA_PERMISSION_GRANTED will be attached to the PendingIntent to indicate success or failure. If successful, this grants the caller permission to access the device only until the device is disconnected. 
Params:
  • accessory – to request permissions for
  • pi – PendingIntent for returning result
/**
     * Requests temporary permission for the given package to access the accessory.
     * This may result in a system dialog being displayed to the user
     * if permission had not already been granted.
     * Success or failure is returned via the {@link android.app.PendingIntent} pi.
     * The boolean extra {@link #EXTRA_PERMISSION_GRANTED} will be attached to the
     * PendingIntent to indicate success or failure.
     * If successful, this grants the caller permission to access the device only
     * until the device is disconnected.
     *
     * @param accessory to request permissions for
     * @param pi PendingIntent for returning result
     */
    public void requestPermission(UsbAccessory accessory, PendingIntent pi) {
        try {
            mService.requestAccessoryPermission(new android.hardware.usb.UsbAccessory(
                    accessory.getManufacturer(),accessory.getModel(),
                    accessory.getDescription(), accessory.getVersion(),
                    accessory.getUri(), accessory.getSerial()),
                    mContext.getPackageName(), pi);
        } catch (RemoteException e) {
            Log.e(TAG, "RemoteException in requestPermission", e);
        }
    }
}