code: public static void showLoading(@NonNull View loadingView, @NonNull View contentView,
        @NonNull View errorView) {
  
      contentView.setVisibility(View.GONE);
      errorView.setVisibility(View.GONE);
      loadingView.setVisibility(View.VISIBLE);
    }
docs: Show the loading view. No animations, because sometimes loading things is pretty fast (i.e.
  retrieve data from memory cache).