Android RSSI value of Bluetooth returns -32768 always?

Question

I am trying to get the current RSSI value of a connected bluetooth device at the click of a button. However it returns only -32768 always! Don't know what is wrong! However I was able to get the correct RSSI, the first time it got connected.

private Button.OnClickListener buttonRSSIOnClickListener = new Button.OnClickListener(){
  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   Intent intent = new Intent(BluetoothDevice.ACTION_FOUND);
   short rssi = intent.getShortExtra(BluetoothDevice.EXTRA_RSSI,Short.MIN_VALUE);
   Toast.makeText(getApplicationContext(),"  RSSI: " + rssi + "dBm", Toast.LENGTH_SHORT).show();

  }};

Can anyone help me please?

Answer 1

This isn't how you use an Intent. You are getting -32768 because the RSSI isn't in that Intent that you just created, and the default result you have specified is Short.MIN_VALUE (-32768).

You need to subclass BroadcastReceiver, and create an IntentFilter (or use the manifest) to so that you receive the BluetoothDevice.ACTION_FOUND intent.

You won't be able to do this "at the click of a button." You'll only get it when Android generates the ACTION_FOUND.

Here is something close. Haven't run it myself.

In onCreate():

registerReceiver(receiver, new IntentFilter(BluetoothDevice.ACTION_FOUND));

Elsewhere:

private final BroadcastReceiver receiver = new BroadcastReceiver(){
    @Override
    public void onReceive(Context context, Intent intent) {

        String action = intent.getAction();
        if(BluetoothDevice.ACTION_FOUND.equals(action)) {
            short rssi = intent.getShortExtra(BluetoothDevice.EXTRA_RSSI,Short.MIN_VALUE);
            Toast.makeText(getApplicationContext(),"  RSSI: " + rssi + "dBm", Toast.LENGTH_SHORT).show();
        }
    }
};

EDIT: Actually you might be able to do it on-demand if you call startDiscovery() on your BluetoothAdapter from within onClick(). That should trigger ACTION_FOUND for each device it discovers.