@Override
 protected void onPostExecute(User user) {
   if (user == null) {
     mListener.onFinish(null);
     return;
   }
   UserData userData = new UserData(user);
   mApp.setUserData(userData);
   mListener.onFinish(userData);
 }
 @Override
 protected void onPostExecute(List<Carta> result) {
   super.onPostExecute(result);
   asyncTaskListener.onFinish(result);
 }