Bluetooth SCO fails after incoming call

Question

I am trying to send all the audio of an application via SCO.

I am able to successfully send the audio,

But when an incoming call comes I need to disconnect form SCO so that the application audio will not interfere with the call,

The problem is that, when I try to reroute the audio to SCO after the call, it does not work.

Here is the code I use to send the audio to SCO:

public class BluetoothManager {
// For Bluetooth connectvity
private static String TAG = "BluetoothManager";
private static BluetoothAdapter mBluetoothAdapter =    BluetoothAdapter.getDefaultAdapter();
private static AudioManager aM;

/**
 * Set the audio manager of the device.
 * @param c: The context this method is called from
 */
public static void setAudioManager(Context c) {
    aM = (android.media.AudioManager)c.getSystemService(Context.AUDIO_SERVICE);
}

/**
 * Check if a Bluetooth headset is connected. If so, route audio to Bluetooth SCO.
 */
private static void initializeAudioMode(Context context) {
    BluetoothProfile.ServiceListener mProfileListener = new BluetoothProfile.ServiceListener() {
        public void onServiceConnected(int profile, BluetoothProfile proxy) {
            if (profile == BluetoothProfile.HEADSET) {
                BluetoothHeadset bh = (BluetoothHeadset) proxy;
                List<BluetoothDevice> devices = bh.getConnectedDevices();
                if (devices.size() > 0) {
                    enableBluetoothSCO();
                }
            }
            mBluetoothAdapter.closeProfileProxy(profile, proxy);
        }
        public void onServiceDisconnected(int profile) {}
    };
    mBluetoothAdapter.getProfileProxy(context, mProfileListener, BluetoothProfile.HEADSET);
}

/**
 * Bluetooth Connectvity
 *   The following methods are associated with enabling/disabling Bluetooth.
 *   In the future we may want to disable other sources of audio.
 */
private static void enableBluetoothSCO() {
    aM.setMode(AudioManager.MODE_IN_CALL);
    aM.startBluetoothSco();
    aM.setBluetoothScoOn(true);
}

/** Right now, this simply enables Bluetooth */
@SuppressLint("NewApi")
public static boolean enableBluetooth(Context c) {
    // If there is an adapter, enable it if not already enabled
    if (mBluetoothAdapter != null) {

        if (!mBluetoothAdapter.isEnabled()) {
            mBluetoothAdapter.enable(); 
        }

        setAudioManager(c);
        initializeAudioMode(c);
        Log.e(TAG, "SCO: " + aM.isBluetoothScoOn());
        Log.e(TAG, "A2DP: " + aM.isSpeakerphoneOn());
        return true;
    } else {
        Log.v(TAG, "There is no bluetooth adapter");
        return false;
    }
}

/** Right now, this simply disables Bluetooth */
public static void disableBluetooth() {
    // If there is an adapter, disabled it if not already disabled
    if (mBluetoothAdapter != null) {
        if (mBluetoothAdapter.isEnabled()) {
            mBluetoothAdapter.disable(); 
        }
    } else {
        Log.v(TAG, "There is no bluetooth adapter");
    }
}

public static void restartBluetooth(){
    aM.setMode(AudioManager.MODE_IN_CALL);

}
public static void stopBluetooth(){
    aM.setMode(AudioManager.MODE_NORMAL);

}

}

When I call stopBluetooth() correctly the audio of the application is not sent to the headset anymore,

But when I call restartBluetooth() the audio plays NOT form the headset as intended, but from the phone speakers.

Answer 1

Is it possible that the SCO link was brought down after the call ended? If this is the case then the SCO link would also have to be brought up along with routing the audio.

Have you tried calling enableBluetoothSCO() within restartBluetooth()

Answer 2

You probably need to call:

aM.startBluetoothSco(); aM.setBluetoothScoOn(true);

after you set the mode.