Android实现主动连接蓝牙耳机

在Android程序中可以实现自动扫描蓝牙、配对蓝牙、建立数据通道。蓝牙分不同类型，这篇文字只讨论如何与蓝牙耳机连接。
大致可以分三步：

一、扫描蓝牙设备：
1、注册并监听广播：

BluetoothAdapter.ACTION_DISCOVERY_STARTED
BluetoothDevice.ACTION_FOUND
BluetoothAdapter.ACTION_DISCOVERY_FINISHED

启动扫描：

BluetoothAdapter.getDefaultAdapter().startDiscovery();

对扫描的结果按类型进行筛选，只保留我们需要的蓝牙耳机：

		if(device.getBluetoothClass().getDeviceClass() == BluetoothClass.Device.AUDIO_VIDEO_WEARABLE_HEADSET
				|| device.getBluetoothClass().getDeviceClass() == BluetoothClass.Device.AUDIO_VIDEO_HANDSFREE){
//蓝牙耳机
}

二、配对指定的蓝牙设备：
这个跟配对普通蓝牙一样，方法如下：

	public static  boolean createBond(BluetoothDevice btDevice){
		boolean result = false;
		try{
			Method m = btDevice.getClass().getDeclaredMethod("createBond",new Class[]{});
			m.setAccessible(true);
			Boolean originalResult = (Boolean) m.invoke(btDevice);
			result = originalResult.booleanValue();
		}catch(Exception ex){
		}
		return result;
	}

等配对完成之后就是要建立数据连接；

三、建立数据连接：

if you SDK between 11 and 16.call a2dp.connectSink(btDevice) or a2dp.connect(btDevice)

private static IBluetoothA2dp getIBluetoothA2dp() {
    IBluetoothA2dp ibta = null;

    try {
        final Class serviceManager = Class.forName("android.os.ServiceManager");
        final Method getService = serviceManager.getDeclaredMethod("getService", String.class);
        final IBinder iBinder = (IBinder) getService.invoke(null, "bluetooth_a2dp");
        final Class iBluetoothA2dp = Class.forName("android.bluetooth.IBluetoothA2dp");
        final Class[] declaredClasses = iBluetoothA2dp.getDeclaredClasses();
        final Class c = declaredClasses[0];
        final Method asInterface = c.getDeclaredMethod("asInterface", IBinder.class);

        asInterface.setAccessible(true);
        ibta = (IBluetoothA2dp) asInterface.invoke(null, iBinder);
    } catch (final Exception e) {
        Log.e("Error " + e.getMessage());
    }
    return ibta;
}

参考：http://stackoverflow.com/questions/8467178/working-around-a2dp-and-hfp-limitations-of-android-pre-honeycomb

如果API大于16需要用如下的方法：

	private void initA2dpService(){
//		Intent i = getExplicitIntent(mContext,new Intent(IBluetoothA2dp.class.getName()));//5.0以上系统需要显示intent
		Intent i = new Intent(IBluetoothA2dp.class.getName());
		boolean success = mContext.bindService(i, mConnection, Context.BIND_AUTO_CREATE);
		if (success) {

		} else {
		}
	}

	public ServiceConnection mConnection = new ServiceConnection() {

		@Override
		public void onServiceConnected(ComponentName name, IBinder service) {
			try {
				mA2dpService = IBluetoothA2dp.Stub.asInterface(service);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

		@Override
		public void onServiceDisconnected(ComponentName name) {
			// TODO Auto-generated method stub

		}

	};
	
    public Intent getExplicitIntent(Context context, Intent implicitIntent) {
        // Retrieve all services that can match the given intent
        PackageManager pm = context.getPackageManager();
        List<ResolveInfo> resolveInfo = pm.queryIntentServices(implicitIntent, 0);
        // Make sure only one match was found
        if (resolveInfo == null || resolveInfo.size() != 1) {
            return null;
        }
        // Get component info and create ComponentName
        ResolveInfo serviceInfo = resolveInfo.get(0);
        String packageName = serviceInfo.serviceInfo.packageName;
        String className = serviceInfo.serviceInfo.name;
        ComponentName component = new ComponentName(packageName, className);
        // Create a new intent. Use the old one for extras and such reuse
        Intent explicitIntent = new Intent(implicitIntent);
        // Set the component to be explicit
        explicitIntent.setComponent(component);
        return explicitIntent;
    }

建立连接：mA2dpService.connect(device);
断开连接：mA2dpService.disconnect(device);

参考：http://stackoverflow.com/questions/14705167/how-connect-paired-bluetooth-a2dp-device-on-android-4-2-using-reflection

http://blog.csdn.net/qs_csu/article/details/45114251