@Override
 public void onSuccess(int statusCode, Header[] headers, String responseString) {
   Response response = Response.getResponse(responseString);
   if (response.getCode() == ResponseCode.SUCCESS) {
     listener.onSuccess();
   } else {
     listener.onFailure(response.getCode());
   }
 }
 @Override
 public void onFailure(
     int statusCode, Header[] headers, String responseString, Throwable throwable) {
   listener.onFailure(ResponseCode.ERROR_NETWORK);
 }