BroadcastReceiver never called

Question

I am trying to scan for bluetooth devices, but the register is never called:

 public class MainActivity extends Activity {


          ArrayList<String> arr_devices = new ArrayList<String>();
          ArrayList<String> arr_in_range = new ArrayList<String>();
          Button btn_devices;
          BluetoothAdapter bluetoothAdapter;
          IntentFilter filter;


        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);

            bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

            btn_devices = (Button)findViewById(R.id.search);
            btn_devices.setOnClickListener(new View.OnClickListener() {


                @Override
                public void onClick(View v) {

                    BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();
                    if (bluetooth != null)
                    {
                        if (bluetooth.isEnabled())
                        {
                            //this is called
                            bluetoothAdapter.startDiscovery();
                            Log.i("State", bluetoothAdapter.getState() + ""); //12 (STATE_ON)
                            Log.i("Discovery", bluetoothAdapter.isDiscovering() + "");  //FALSE

                            filter = new IntentFilter();
                            filter.addAction(BluetoothDevice.ACTION_FOUND);
                            filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
                            filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);

                           registerReceiver(myreceiver, filter);
                           //this is where the program stops. No more actions are performed
                        }
                        else
                        {
                            Toast.makeText(getApplicationContext(), "Bluetooth is not enabled!", Toast.LENGTH_SHORT).show();
                        }
                    }
                }
            });


        }


        @Override
        protected void onDestroy() {

            super.onDestroy();
            unregisterReceiver(myreceiver);
        }


        final BroadcastReceiver myreceiver = new BroadcastReceiver(){

        @Override
        public void onReceive(Context context, Intent intent) {
        //I placed a Log statement here but it doesn't appear in the logcat
           String action = intent.getAction();

           if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
           }
           else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
           }

           if(BluetoothDevice.ACTION_FOUND.equals(action)) 
           {
               BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
               Log.i("device", device.getName() + "\n" + device.getAddress());
           }

         }};

    }

Bluetooth is enabled. What am I missing?

Answer 1

Try to put your broadcast receiver before

 bluetoothAdapter.startDiscovery();

Cause you startDiscovery and after you listen broadcastListener.

Answer 2

Why do you have two bluetooth adapters set up? The system might be getting confused with both of them, you should only need one. I recommend you remove the line listed below, and change all references from bluetooth to bluetoothAdapter.

BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();

I suspect what is happening is that this is returning null, as you already have a copy of the receiver, or something similar to that.

Also, make sure you have added the permissions to the manifest:

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

All of that failing, you might try rebooting your phone. At least on my phone, bluetooth gets mucked up sometimes.