参考：
Android实现主动连接蓝牙耳机
具体实现：
private static final String TAG = "BluetoothA2DPTest";
private BroadcastReceiver mBroadcastReceiver;
private BluetoothA2dp mBluetoothA2dp;
private BluetoothAdapter mBluetoothAdapter;
private String DEVICE_NAME = "KUWO_K1";
private BluetoothDevice mBluetoothDevice;
private MediaPlayer mMediaPlayer; private void initParameters(){
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter == null){
Log.e(TAG,"have no bluetooth adapter.");
return;
} if(!mBluetoothAdapter.isEnabled()){
mBluetoothAdapter.enable();
}else{
//开始搜索附近蓝牙
startDiscovery();
//绑定BluetoothA2DP，获得service
getBluetoothA2DP();
} //监听广播
mBroadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
BluetoothDevice device;
switch (intent.getAction()) {
case BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED:
//<editor-fold>
switch (intent.getIntExtra(BluetoothA2dp.EXTRA_STATE, -1)) {
case BluetoothA2dp.STATE_CONNECTING:
device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Log.i(TAG, "device: " + device.getName() +" connecting");
break;
case BluetoothA2dp.STATE_CONNECTED:
device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Log.i(TAG, "device: " + device.getName() +" connected");
//连接成功，开始播放
startPlay();
break;
case BluetoothA2dp.STATE_DISCONNECTING:
device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Log.i(TAG, "device: " + device.getName() +" disconnecting");
break;
case BluetoothA2dp.STATE_DISCONNECTED:
device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Log.i(TAG, "device: " + device.getName() +" disconnected");
// setResultPASS();
break;
default:
break;
}
//</editor-fold>
break;
case BluetoothA2dp.ACTION_PLAYING_STATE_CHANGED:
//<editor-fold>
int state = intent.getIntExtra(BluetoothA2dp.EXTRA_STATE, -1);
switch (state) {
case BluetoothA2dp.STATE_PLAYING:
Log.i(TAG, "state: playing.");
break;
case BluetoothA2dp.STATE_NOT_PLAYING:
Log.i(TAG, "state: not playing");
break;
default:
Log.i(TAG, "state: unkown");
break;
}
//</editor-fold>
break;
case BluetoothDevice.ACTION_FOUND:
//<editor-fold>
device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
int deviceClassType = device.getBluetoothClass().getDeviceClass();
//找到指定的蓝牙设备
if ((deviceClassType == BluetoothClass.Device.AUDIO_VIDEO_WEARABLE_HEADSET
|| deviceClassType == BluetoothClass.Device.AUDIO_VIDEO_HEADPHONES)
&& device.getName().equals(DEVICE_NAME)) {
Log.i(TAG, "Found device:" + device.getName());
mBluetoothDevice = device;
//start bond，开始配对
createBond();
}
//</editor-fold>
break;
case BluetoothDevice.ACTION_BOND_STATE_CHANGED:
//<editor-fold>
int bondState = intent.getIntExtra(BluetoothDevice.EXTRA_BOND_STATE,BluetoothDevice.BOND_NONE);
device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
switch (bondState){
case BluetoothDevice.BOND_BONDED: //配对成功
Log.i(TAG,"Device:"+device.getName()+" bonded.");
mBluetoothAdapter.cancelDiscovery(); //取消搜索
connect(); //连接蓝牙设备
break;
case BluetoothDevice.BOND_BONDING:
Log.i(TAG,"Device:"+device.getName()+" bonding.");
break;
case BluetoothDevice.BOND_NONE:
Log.i(TAG,"Device:"+device.getName()+" not bonded.");
//不知道是蓝牙耳机的关系还是什么原因，经常配对不成功
//配对不成功的话，重新尝试配对
createBond();
break;
default:
break; } //</editor-fold>
break;
case BluetoothAdapter.ACTION_STATE_CHANGED:
//<editor-fold>
state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, -1);
switch (state) {
case BluetoothAdapter.STATE_TURNING_ON:
Log.i(TAG, "BluetoothAdapter is turning on.");
break;
case BluetoothAdapter.STATE_ON:
Log.i(TAG, "BluetoothAdapter is on.");
//蓝牙已打开，开始搜索并连接service
startDiscovery();
getBluetoothA2DP();
break;
case BluetoothAdapter.STATE_TURNING_OFF:
Log.i(TAG, "BluetoothAdapter is turning off.");
break;
case BluetoothAdapter.STATE_OFF:
Log.i(TAG, "BluetoothAdapter is off.");
break;
}
//</editor-fold>
break;
default:
break;
}
}
};
IntentFilter filter = new IntentFilter();
filter.addAction(BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED);
filter.addAction(BluetoothA2dp.ACTION_PLAYING_STATE_CHANGED);
filter.addAction(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mBroadcastReceiver, filter);
} private void startDiscovery(){
Log.i(TAG,"mBluetoothAdapter startDiscovery.");
if(mBluetoothAdapter!=null && mBluetoothAdapter.isEnabled() && !mBluetoothAdapter.isDiscovering()){
mBluetoothAdapter.startDiscovery();
}
} private void getBluetoothA2DP(){
Log.i(TAG,"getBluetoothA2DP");
if(mBluetoothAdapter == null){
return;
} if(mBluetoothA2dp != null){
return;
} mBluetoothAdapter.getProfileProxy(this, new BluetoothProfile.ServiceListener() {
@Override
public void onServiceConnected(int profile, BluetoothProfile proxy) {
if(profile == BluetoothProfile.A2DP){
//Service连接成功，获得BluetoothA2DP
mBluetoothA2dp = (BluetoothA2dp)proxy;
}
} @Override
public void onServiceDisconnected(int profile) { }
},BluetoothProfile.A2DP);
} private void createBond() {
Log.i(TAG, "createBond");
mBluetoothDevice.createBond();
} //connect和disconnect都是hide方法，普通应用只能通过反射机制来调用该方法
private void connect(){
Log.i(TAG,"connect");
if(mBluetoothA2dp == null){
return;
}
if(mBluetoothDevice == null){
return;
} try {
Method connect = mBluetoothA2dp.getClass().getDeclaredMethod("connect", BluetoothDevice.class);
connect.setAccessible(true);
connect.invoke(mBluetoothA2dp,mBluetoothDevice);
} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
Log.e(TAG,"connect exception:"+e);
e.printStackTrace();
}
} private void startPlay(){
Log.i(TAG, "startPlay");
AudioManager mAudioManager= (AudioManager)getSystemService(AUDIO_SERVICE);
if(mAudioManager!=null){
int maxVolume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC,maxVolume,0);
} Uri uri = Uri.parse("android.resource://"+getPackageName()+"/"+ R.raw.speaker_test);
mMediaPlayer = new MediaPlayer();
mMediaPlayer.reset();
try {
mMediaPlayer.setDataSource(this,uri);
mMediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
//播放完成，可以考虑断开连接
disconnect();
}
});
mMediaPlayer.setOnErrorListener(new MediaPlayer.OnErrorListener() {
@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
Log.e(TAG, "Playback error.");
return false;
}
});
mMediaPlayer.prepare();
mMediaPlayer.start();
} catch(IllegalStateException|IOException e) {
Log.e(TAG, "Exception: prepare or start mediaplayer");
setResultFAIL();
}
} //程序退出前，要release播放器
private void stopPlay(){
Log.i(TAG,"stopPlay");
if(mMediaPlayer!=null){
mMediaPlayer.stop();
mMediaPlayer.release();
mMediaPlayer = null;
}
} private void disconnect(){
Log.i(TAG,"disconnect");
if(mBluetoothA2dp == null){
return;
}
if(mBluetoothDevice == null){
return;
} try {
Method disconnect = mBluetoothA2dp.getClass().getDeclaredMethod("disconnect", BluetoothDevice.class);
disconnect.setAccessible(true);
disconnect.invoke(mBluetoothA2dp,mBluetoothDevice);
} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
Log.e(TAG,"connect exception:"+e);
e.printStackTrace();
}
} //取消配对
private void unPairAllDevices(){
Log.i(TAG,"unPairAllDevices");
for(BluetoothDevice device:mBluetoothAdapter.getBondedDevices()){
try {
Method removeBond = device.getClass().getDeclaredMethod("removeBond");
removeBond.invoke(device);
} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
e.printStackTrace();
}
}
} //注意，在程序退出之前（OnDestroy），需要断开蓝牙相关的Service
//否则，程序会报异常：service leaks
private void disableAdapter(){
Log.i(TAG,"disableAdapter");
if(mBluetoothAdapter == null){
return;
} if(mBluetoothAdapter.isDiscovering()){
mBluetoothAdapter.cancelDiscovery();
} //关闭ProfileProxy，也就是断开service连接
mBluetoothAdapter.closeProfileProxy(BluetoothProfile.A2DP,mBluetoothA2dp);
if(mBluetoothAdapter.isEnabled()){
boolean ret = mBluetoothAdapter.disable();
Log.i(TAG,"disable adapter:"+ret);
}
}