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.