title: I can not get registration ID from Android GCM
body: <p>Although I try other answer about this problem, it can't be solved.
  Sender ID is correct, permissions are added, API key is true.</p>
  
  <p>I use this post for creating the project:
  <a href="http://developer.android.com/guide/google/gcm/gs.html#server-app">http://developer.android.com/guide/google/gcm/gs.html#server-app</a></p>
  
  <pre><code>    GCMRegistrar.checkDevice(this);
      GCMRegistrar.checkManifest(this);
      String regId = GCMRegistrar.getRegistrationId(this);
      if (regId.equals("")) {
        GCMRegistrar.register(this, SENDER_ID);
        regId = GCMRegistrar.getRegistrationId(this);
      } else {
        Log.v(TAG, "Already registered");
      }
      String did = getDeviceID();
  </code></pre>
  
  <p>it returns empty string. </p>