Set Active A2DP Device in Android

Question

I've been working on a code to send short audio messages to inexpensive bluetooth earpieces.

I want to be able to select the current audio output device with A2DP, and there does not seem to be any reliable way to do this.

I know how to get the A2DP profile, and use reflection to connect and disconnect devices.

BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
public BluetoothA2dp mA2DP;

mBluetoothAdapter.getProfileProxy(this, mProfileListener, BluetoothProfile.A2DP);

private BluetoothProfile.ServiceListener mProfileListener = new BluetoothProfile.ServiceListener() {
        public void onServiceConnected(int profile, BluetoothProfile proxy) {
            if (profile == BluetoothProfile.A2DP) {
                mA2DP = (BluetoothA2dp) proxy;
            }
        }

        @Override
        public void onServiceDisconnected(int profile) {
            if (profile==BluetoothProfile.A2DP) {
                mA2DP = null;
            }
        }
    };

And with the A2DP profile, you can use reflection to access the connect and disconnect methods:

public void disconnectA2DP(BluetoothDevice bd) {
    if (mA2DP==null) return;
    try {
        Method m = BluetoothA2dp.class.getDeclaredMethod("disconnect", BluetoothDevice.class); 
        m.invoke(mA2DP,bd);
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    }
}

(Connect is the same apart from use "connect" for the method name)

All this works fine. You can then use GetConnectedDevices to find out which devices are currently connected.

Older phones only seem to support one device, so this mechanism works fine for switching outputs. However, later phones (specifically Samsung) seem to support TWO devices at the same time. There does not appear to be any way of selecting which device the audio is going to. I can disconnect the one I DON'T want, but some devices have an annoying habit of reconnecting without being asked, and making themselves the active output.

In the source code for BluetoothA2dp you can clearly see "setActiveDevice", but it does not seem to be accessible to applications, even through reflection.

Any help appreciated.

Edit: Partial kludgy solution: Empirically, the last BluetoothDevice in the devices list is the active one. If it's not the one I want, I disconnect the FIRST one in the list, and connect the one I DO want. This seems to work but does not strike me as the best possible solution.