// @Override
 public void onCourseDeletionComplete(Payload response) {
   if (response.isResult()) {
     updateLastScan(0);
   }
   if (progressDialog != null) {
     progressDialog.dismiss();
   }
   Toast.makeText(
           OppiaMobileActivity.this,
           getString(
               response.isResult()
                   ? R.string.course_deleting_success
                   : R.string.course_deleting_error),
           Toast.LENGTH_LONG)
       .show();
   displayCourses(userId);
 }
 public void updateActivityComplete(Payload response) {
   Course course = (Course) response.getData().get(0);
   if (progressDialog != null) {
     progressDialog.dismiss();
   }
   Toast.makeText(
           OppiaMobileActivity.this,
           getString(
               response.isResult()
                   ? R.string.course_updating_success
                   : R.string.course_updating_error,
               (course != null) ? course.getShortname() : ""),
           Toast.LENGTH_LONG)
       .show();
   displayCourses(userId);
 }