title: Unable to get non-empty string from PhoneStateListener::onCallStateChanged
body: <p>Source:  </p>
  
  <pre><code>listener = new PhoneStateListener()
      {
          @Override
          public void onCallStateChanged(int state, String incomingNumber) {
              super.onCallStateChanged(state, incomingNumber);
              Toast toast = Toast.makeText(getApplicationContext(), incomingNumber, Toast.LENGTH_LONG);
              toast.show();
          }
  
      };
  
      ((TelephonyManager)getSystemService(TELEPHONY_SERVICE)).listen(listener , PhoneStateListener.LISTEN_CALL_STATE )
  </code></pre>
  
  <p>Hi,<br>
  I am using this code, with <code>android.permission.READ_PHONE_STATE</code> permission, to get toast message including number of started call. My problem is that incomingNumber is empty, it doest not matter if call is outgoing or incomming, toast appear, but empty.<br>
  I have seen some solutions for this, but solution was to get the number with completely different way and I wanna know if my code can be used for my needs.<br>
  Thanks for advices,<br>
  Adam</p>