How to check whether bluetooth has connected with other device programatically using Async Task?

Issue

I need to check whether any device is connected and communicating to my device via bluetooth in doInBackground method in Async Task. If connected/communicating - display toast message as "Connected". if not display as "No device connected".

I've searched everywhere, but no answers satisfied my requirements.

Solution

I do not know your problem in detail, but my Solution would be the BroadhastReceiver for Bluetooth Adapter.

public class AnyActivity extends AppCompatActivity {

private BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
private static boolean isConnected = false;
private static boolean isConnecting = false;
private static boolean isDisdconected = false;

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_any);

        IntentFilter BT_ConState_filter  = new 
        IntentFilter(BluetoothAdapter.ACTION_CONNECTION_STATE_CHANGED);

        this.registerReceiver(BR_BT_ConState, BT_ConState_filter);
}

BroadcastReceiver BR_BT_ConState =new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action_BR_BT_ConState =intent.getAction();
            int iBR_BT_ConState_state = intent.getIntExtra(BluetoothAdapter.EXTRA_CONNECTION_STATE, mBluetoothAdapter.ERROR);

            if (action_BR_BT_ConState.equals(mBluetoothAdapter.ACTION_CONNECTION_STATE_CHANGED))
            {
                switch (iBR_BT_ConState_state) {
                    case BluetoothAdapter.STATE_CONNECTING:
                        Toast.makeText(this, "Connecting" ,Toast.LENGTH_SHORT).show();
                        isConnected = false;
                        isConnecting = true;
                        isDisdconected = false;
                        break;

                    case BluetoothAdapter.STATE_CONNECTED:
                        Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
                        isConnected = true;
                        isConnecting = false;
                        isDisdconected = false;
                        break;

                    case BluetoothAdapter.STATE_DISCONNECTED:
                        Toast.makeText(this, "Disconected", Toast.LENGTH_SHORT).show();
                        isConnected = false;
                        isConnecting = false;
                        isDisdconected = true;
                        break;
                }
            }
        }
    };

public static boolean isConnected(){
return isConnected;
}

public static boolean isDisConnected(){
return isDisConnected;
}

public static boolean isConnecting(){
return isDisConnected;
}

@Override
    protected void onDestroy(){
        super.onDestroy();
        context.unregisterReceiver(BR_BT_ConState);
    }
}

If you tell me what you want to do exactly, for example: Run Some Code depending on state, Execute some TextView Changes, Or something like a callback Method,

or what else, I can try to help you even more.

What I did now is creating some static functions you should be able to call in your AsynkTask, just call AnyActivity.isConnected() and you get the current state of the BluetoothAdapter returned.

Answered By - Alpha-Centauri