蓝牙耳机无法听到蓝牙SCO音频

我是android新手 . 我正在尝试将手机的麦克风音频路由到蓝牙耳机（Microlab T2） . 我的代码如下

public class MainActivity extends AppCompatActivity {


BluetoothAdapter bluetoothAdapter;
BluetoothDevice blueToothDevice;
BluetoothHeadset bluetoothHeadset;
AudioManager audioManager;
BluetoothManager bluetoothManager;
BluetoothSocket bluetoothSocket;

int b;
final Context con = this;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final StringBuilder stringBuilder = new StringBuilder();

    final TextView txt2 = (TextView) findViewById(R.id.textView2);

    try {




        final TextView txt = (TextView) findViewById(R.id.textView);



        bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
        audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);


        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

        bluetoothAdapter.cancelDiscovery();

        Set<BluetoothDevice> getDevices = bluetoothAdapter.getBondedDevices();

        String remoteDevice = null;

        for (BluetoothDevice getDevice : getDevices) {

            stringBuilder.append(getDevice);
            remoteDevice = getDevice.toString();

        }

         // txt.setText(stringBuilder);

        blueToothDevice = bluetoothAdapter.getRemoteDevice(remoteDevice);

        bluetoothAdapter.getProfileProxy(this, listener, BluetoothProfile.HEADSET);


    } catch (Exception e) {
        TextView txt = (TextView) findViewById(R.id.textView);
        txt.setText(e.toString());
    }

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}


public final BluetoothProfile.ServiceListener listener = new BluetoothProfile.ServiceListener() {
    @Override

    public void onServiceConnected(int i, BluetoothProfile bluetoothProfile) {

        final BluetoothProfile bluetoothProfileNew ;

            final TextView txt = (TextView) findViewById(R.id.textView);


            bluetoothHeadset = (BluetoothHeadset) bluetoothProfile;

        Record record = new Record(bluetoothProfile);

        record.start();

    }

    @Override
    public void onServiceDisconnected(int i) {
        final TextView txt = (TextView) findViewById(R.id.textView);

        txt.setText(String.valueOf(i));
    }
};

  class Record extends Thread {

    BluetoothProfile recordProfile;


    final int bufferSize = 200000;
    final short[] buffer = new short[bufferSize];
    short[] readBuffer = new short[bufferSize];


    public Record(BluetoothProfile profile) {

        recordProfile = profile;
        android.os.Process.setThreadPriority
                (android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);



    }

    public void run() {





        final TextView txt2 = (TextView) findViewById(R.id.textView2);


        b = AudioRecord.getMinBufferSize(44100, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);

        audioManager.startBluetoothSco();

        audioManager.setSpeakerphoneOn(false);
        audioManager.setBluetoothScoOn(true);

        audioManager.setMicrophoneMute(false);
        audioManager.setMode(AudioManager.MODE_IN_CALL);








       audioManager.setStreamVolume(AudioManager.STREAM_VOICE_CALL, 50 , 2);

        final AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,
                44100, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, 44100);

        final AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_VOICE_CALL,44100, AudioFormat.CHANNEL_OUT_MONO,
                AudioFormat.ENCODING_PCM_16BIT, b*10, AudioTrack.MODE_STREAM);


        int buffersize = b;


        audioRecord.startRecording();


     //audioTrack.setPlaybackRate(44100)   ;
        audioTrack.play();


        // txt2.setText(String.valueOf(audioManager.isBluetoothScoOn()));



       final BluetoothProfile b = recordProfile;

        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                /// TextView txt2 = (TextView) findViewById(R.id.textView2);

                try {
                 //   final String m = String.valueOf(audioTrack.getRoutedDevice());

                   // txt2.setText(String.valueOf(bluetoothHeadset.isAudioConnected(blueToothDevice)));
                   txt2.setText(String.valueOf(audioRecord.getRecordingState()));

                } catch (Exception e) {
                    txt2.setText(e.toString());
                }


            }
        });


        byte[] buffer2 = new byte[buffersize];

        while (true) {
            audioRecord.read(buffer2, 0, buffersize);
            audioTrack.write(buffer2, 0, buffer2.length);
        }


    }


}


}

运行此代码后，我听不到耳机的任何音频 . 但当我调试（通过BluetoothHeadset，AudioManager，AudioRecord，AudioTrack类的方法）代码时，我发现了

• 成功启动SCO连接

• 正在播放SCO音频

• MIC音频正在录音

• 正在播放音频

但最后我听不到耳机的任何声音 . 我尝试了各种可能的原因，但没有运气 . 现在我完全无能为力 .

期待您的建议 .