在我们的应用程序中，我想使用Android v4.2或更高版本连接到之前配对的A2DP蓝牙扬声器并直接播放音频。
我可以使用此代码成功创建A2DP配置文件对象以启动该过程：
/* Manifest permissions */
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
// Get the default adapter
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
// Establish connection to the proxy.
mBluetoothAdapter.getProfileProxy(this, mProfileListener, BluetoothProfile.A2DP)
以下监听器响应连接：
private BluetoothProfile.ServiceListener mProfileListener = new BluetoothProfile.ServiceListener() {
public void onServiceConnected(int profile, BluetoothProfile proxy) {
if (profile == BluetoothProfile.A2DP) {
mBluetoothSpeaker = (BluetoothA2dp) proxy;
// no devices are connected
List<BluetoothDevice> connectedDevices = mBluetoothSpeaker.getConnectedDevices();
//the one paired (and disconnected) speaker is returned here
int[] statesToCheck = {BluetoothA2dp.STATE_DISCONNECTED};
List<BluetoothDevice> disconnectedDevices = mBluetoothSpeaker.getDevicesMatchingConnectionStates(statesToCheck);
BluetoothDevice btSpeaker = disconnectedDevices.get(0);
//WHAT NOW?
}
}
public void onServiceDisconnected(int profile) {
if (profile == BluetoothProfile.A2DP) {
mBluetoothSpeaker = null;
}
}
};
关于现在该做什么，我只是有点迷失，连接设备，并将音频输出定向到它。我尝试使用以下代码连接到设备as detailed in the Android docs，但最终的BluetoothSpeaker.getConnectedDevices()调用不会返回任何已连接的设备。
BluetoothSocket tmp = null;
UUID MY_UUID = UUID.fromString("00001108-0000-1000-8000-00805f9b34fb");
try {
tmp = btSpeaker.createInsecureRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e1) {
// TODO Auto-generated catch block
Log.d("createRfcommSocketToServiceRecord ERROR", e1.getMessage());
}
mmSocket = tmp;
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mmSocket.connect();
} catch (IOException connectException) {
// Unable to connect; close the socket and get out
try {
Log.d("connectException", connectException.getMessage());
mmSocket.close();
} catch (IOException closeException) { }
return;
}
connectedDevices = mBluetoothSpeaker.getConnectedDevices();
代码似乎确实以某种方式连接到设备，因为当我停止执行时，蓝牙扬声器宣布它已准备好配对（就像它从音频源断开时一样）。
BluetoothA2dp的旧版本似乎有一个connect(BluetoothDevice device)方法，但现在已经删除了（截至4.2），我很难找到任何有关如何以编程方式连接到的明确示例A2DP设备，并将音频输出定向到它。我们将非常感激地接受任何关于如何接近的帮助。
如何处理此问题的任何建议都将非常受欢迎。
答案 0 :(得分：8)
这个对我有用。 收到BluetoothA2dp.STATE_CONNECTED后，您可以正常播放音乐。
public class A2DPActivity extends Activity {
protected static final String TAG = "ZS-A2dp";
Button mBtPlay;
BluetoothAdapter mBtAdapter;
BluetoothA2dp mA2dpService;
AudioManager mAudioManager;
MediaPlayer mPlayer;
BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context ctx, Intent intent) {
String action = intent.getAction();
Log.d(TAG, "receive intent for action : " + action);
if (action.equals(BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED)) {
int state = intent.getIntExtra(BluetoothA2dp.EXTRA_STATE, BluetoothA2dp.STATE_DISCONNECTED);
if (state == BluetoothA2dp.STATE_CONNECTED) {
setIsA2dpReady(true);
playMusic();
} else if (state == BluetoothA2dp.STATE_DISCONNECTED) {
setIsA2dpReady(false);
}
} else if (action.equals(BluetoothA2dp.ACTION_PLAYING_STATE_CHANGED)) {
int state = intent.getIntExtra(BluetoothA2dp.EXTRA_STATE, BluetoothA2dp.STATE_NOT_PLAYING);
if (state == BluetoothA2dp.STATE_PLAYING) {
Log.d(TAG, "A2DP start playing");
Toast.makeText(A2DPActivity.this, "A2dp is playing", Toast.LENGTH_SHORT).show();
} else {
Log.d(TAG, "A2DP stop playing");
Toast.makeText(A2DPActivity.this, "A2dp is stopped", Toast.LENGTH_SHORT).show();
}
}
}
};
boolean mIsA2dpReady = false;
void setIsA2dpReady(boolean ready) {
mIsA2dpReady = ready;
Toast.makeText(this, "A2DP ready ? " + (ready ? "true" : "false"), Toast.LENGTH_SHORT).show();
}
private ServiceListener mA2dpListener = new ServiceListener() {
@Override
public void onServiceConnected(int profile, BluetoothProfile a2dp) {
Log.d(TAG, "a2dp service connected. profile = " + profile);
if (profile == BluetoothProfile.A2DP) {
mA2dpService = (BluetoothA2dp) a2dp;
if (mAudioManager.isBluetoothA2dpOn()) {
setIsA2dpReady(true);
playMusic();
} else {
Log.d(TAG, "bluetooth a2dp is not on while service connected");
}
}
}
@Override
public void onServiceDisconnected(int profile) {
setIsA2dpReady(false);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LinearLayout ll = new LinearLayout(this);
setContentView(ll);
mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
registerReceiver(mReceiver, new IntentFilter(BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED));
registerReceiver(mReceiver, new IntentFilter(BluetoothA2dp.ACTION_PLAYING_STATE_CHANGED));
mBtAdapter = BluetoothAdapter.getDefaultAdapter();
mBtAdapter.getProfileProxy(this, mA2dpListener , BluetoothProfile.A2DP);
}
@Override
protected void onDestroy() {
mBtAdapter.closeProfileProxy(BluetoothProfile.A2DP, mA2dpService);
releaseMediaPlayer();
unregisterReceiver(mReceiver);
super.onDestroy();
}
@Override
protected void onPause() {
releaseMediaPlayer();
super.onPause();
}
private void releaseMediaPlayer() {
if (mPlayer != null) {
mPlayer.release();
mPlayer = null;
}
}
private void playMusic() {
mPlayer = new MediaPlayer();
AssetManager assetManager = this.getAssets();
AssetFileDescriptor fd;
try {
fd = assetManager.openFd("Radioactive.mp3");
Log.d(TAG, "fd = " + fd);
mPlayer.setDataSource(fd.getFileDescriptor());
mPlayer.prepare();
Log.d(TAG, "start play music");
mPlayer.start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
答案 1 :(得分：1)
泰德，
当我尝试使用BluetoothHeadset时，我遇到了和你一样的问题。 我想我的工作可能适用于A2DP。 由于我的耳机仅支持免提配置文件。我只用BlueHeadset进行测试。
无需建立RFComm频道。
对我来说。 连接到BluetoothHeadsetService后， 1.检查音频是否已连接
mBluetoothSpeaker.isAudioConnected(btSpeaker);
2。如果没有，建立音频连接
mBluetoothSpeaker.startVoiceRecognition(btSpeaker);
3。注册BroadcastReceiver for BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED和BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED
registerReceiver(mReceiver, new IntentFilter(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED));
registerReceiver(mReceiver, new IntentFilter(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED));
4。广播接收器
protected BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
int state = BluetoothHeadset.STATE_DISCONNECTED;
int previousState = intent.getIntExtra(BluetoothHeadset.EXTRA_PREVIOUS_STATE, BluetoothHeadset.STATE_DISCONNECTED);
if (action.equals(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED)) {
state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE, BluetoothHeadset.STATE_DISCONNECTED);
if (state == BluetoothHeadset.STATE_CONNECTED) {
mConnectedHeadset = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
mInfoTextview.append("\n\nDevice name = " + mConnectedHeadset.getName());
// Audio should not be connected yet but just to make sure.
if (mBluetoothHeadset.isAudioConnected(mConnectedHeadset)) {
Log.d(TAG, "Headset audio connected already");
} else {
if (!mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset)) {
Log.e(TAG, "maybe you do not call stopVoiceRecognition previously");
mBluetoothHeadset.stopVoiceRecognition(mConnectedHeadset);
mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset);
}
}
}
else if (state == BluetoothHeadset.STATE_DISCONNECTED) {
mConnectedHeadset = null;
}
}
else if (action.equals(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED))// audio
{
state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE, BluetoothHeadset.STATE_AUDIO_DISCONNECTED);
if (state == BluetoothHeadset.STATE_AUDIO_CONNECTED) {
// Bluetooth audio connected. you send audio stream to headset now!!!
mAudioManager.setMode(AudioManager.STREAM_VOICE_CALL);
mMediaPlayer = new MediaPlayer();
AssetManager assetManager = getAssets();
try {
AssetFileDescriptor fd = assetManager.openFd("Radioactive.mp3");
mMediaPlayer.setDataSource(fd.getFileDescriptor());
// set audio stream type to STREAM_VOICE_CALL will send audio to headset
// @see <a href="http://developer.android.com/reference/android/media/AudioManager.html#startBluetoothSco()">SCO</a>
mMediaPlayer.setAudioStreamType(AudioManager.STREAM_VOICE_CALL);
mMediaPlayer.prepare();
Log.d(TAG, "start play music");
mMediaPlayer.start();
} catch (IOException e) {
e.printStackTrace();
}
}
else if (state == BluetoothHeadset.STATE_AUDIO_DISCONNECTED) {
if (mMediaPlayer != null) {
mMediaPlayer.stop();
mMediaPlayer = null;
}
mBluetoothHeadset.stopVoiceRecognition(mConnectedHeadset);
}
}
}
};
答案 2 :(得分：0)
有同样的问题，但发现老帖子：
Programmatically connect to paired Bluetooth device
简而言之，为了连接到配对的a2dp设备，你只需要调用BluetoothA2dp.connect（myPairedA2dpDevice），但是现在该方法对公共API是隐藏的，这没有用。所以你通过Java反射访问它。这是一种黑客行为，但谷歌说它的方式，目前似乎并不是一个干净的解决方案。
答案 3 :(得分：0)
mMediaPlayer.setAudioAttributes(new AudioAttributes.Builder()
.setFlags(AudioAttributes.FLAG_AUDIBILITY_ENFORCED)
.setLegacyStreamType(AudioManager.STREAM_MUSIC)
//.setUsage(AudioAttributes.USAGE_ALARM)
.setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
.build());
通过注释.setUsage（AudioAttributes.USAGE_ALARM）行，它对我有用。