Programmatically connect to paired Bluetooth speaker and play audio

Question

In our app, I\'d like to connect to a previously paired A2DP Bluetooth Speaker and direct audio playback to it, using Android v4.2 or later.

I can successfully creat

Answer 1

Ted,

I have the same issue like you when I tried with BluetoothHeadset. I guess my work around may work with A2DP. Since my headset only support Handsfree profile. I am only test with BluetoothHeadset.

No need to establish RFComm channel.

For me. After you connected to BluetoothHeadsetService, 1. check whether audio is already connected

mBluetoothSpeaker.isAudioConnected(btSpeaker);

2. if not, establish audio connection

mBluetoothSpeaker.startVoiceRecognition(btSpeaker);

3. register BroadcastReceiver for BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED and BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED

registerReceiver(mReceiver, new IntentFilter(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED));
registerReceiver(mReceiver, new IntentFilter(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED));

4. BroadcastReceiver

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 SCO
                    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);
            }
        }   
    }
};