Get the Bluetooth headphone MAC address as it is connected in A2DP - sockets

Question

Goal: open a bluetooth socket to a currently connected A2DP device, when I know it is connected.
In order to connect the socket, I need the MAC address of this device.
As i currently understand, there is 2 kinds of listener to get the bluetooth state:
1- BluetoothAdapter.getProfileProxy() as described here How to get bluetooth connected devices using BluetoothHeadset API
triggers when bluetooth card is ON / OFF.
allow to get a specific bluetoothProfile (A2DP for example), then the list of the connected devices to this profile, then the mac address of this connected devices.
the device list is ever empty when "onServiceConnected" is called (devices need more time to connected after the bluetooth card startup). So I need to call it after the device connection.
2- A broadcast receiver on BluetoothDevice.ACTION_ACL_CONNECTED as described here How to programmatically tell if a Bluetooth device is connected? (Android 2.2)
triggers when bluetooth device is connected / disconnected.
do not allow to get any information of this device
So I need to use both of them to trigger when A2DP device is connected... and so get the MAC address of this device (then open the btSocket):
Start the btAdapter.getProfileProxy inside the BroadcastReceiver "BluetoothDevice.ACTION_ACL_CONNECTED", but with a 3 seconds delay to allow it to connect.
It is the only (complicated) way to do that?
onCreate{
context.registerReceiver(mReceiver, new IntentFilter(BluetoothDevice.ACTION_ACL_CONNECTED));
context.registerReceiver(mReceiver, new IntentFilter(BluetoothDevice.ACTION_ACL_DISCONNECTED);
}
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent)
{
Log.d(TAG, "Action received\n");
String action = intent.getAction();
if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action))
{
Log.d(TAG, "ACTION_ACL_CONNECTED received\n");
timerHandler.postDelayed(timerRunnableBtConnection, 3000);
}
else if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action))
{
Log.d(TAG, "ACTION_ACL_DISCONNECTED received\n");
btAdapter.closeProfileProxy(BluetoothProfile.A2DP, btA2dp);
}
}
private Runnable timerRunnableBtConnection = new Runnable() {
#Override
public void run() {
btAdapter.getProfileProxy(intelloApplication.getAppContext(), mProfileListener, BluetoothProfile.A2DP);
}
};
};
// Define Service Listener of BluetoothProfile
// then create the btSocket on it
private BluetoothProfile.ServiceListener mProfileListener = new BluetoothProfile.ServiceListener() {
public void onServiceConnected(int profile, BluetoothProfile proxy) {
if (profile == BluetoothProfile.A2DP) {
Log.d(TAG, "Bluetooth connected\n");
btA2dp = (BluetoothA2dp) proxy;
List<BluetoothDevice> devices = btA2dp.getConnectedDevices();
Log.d(TAG, "List of " + devices.size() + " device\n");
for ( final BluetoothDevice dev : devices ) {
String address = dev.getAddress();
Log.d(TAG, "Name: " + dev.getName() + " and address: " + address + "\n");
btDevice = btAdapter.getRemoteDevice(address);
try {
btSocket = createBluetoothSocket(btDevice);
} catch (IOException e) {
Log.d(TAG, e.getMessage());
}
Log.d(TAG, "...Connecting...");
try {
btSocket.connect();
useBluetooth = true;
Log.d(TAG, "....Connection ok...");
} catch (IOException e) {
try {
btSocket.close();
useBluetooth = false;
Log.d(TAG, "....Close connection.");
} catch (IOException e2) {
Log.d(TAG, "Unable to close socket during connection failure");
Log.d(TAG, e2.getMessage());
}
}
// Create a data stream so we can talk to server.
Log.d(TAG, "...Create Socket...");
mConnectedThread = new ConnectedThread(btSocket);
mConnectedThread.start();
}
}
}
}
public void onServiceDisconnected(int profile) {
if (profile == BluetoothProfile.A2DP) {
Log.d(TAG, "Bluetooth disconnected\n");
}
}
};