code: private void showToast(@Nullable final String text) {
          if (toast != null) {
              toast.cancel();
          }
  
          toast = Toast.makeText(getActivity(), text, Toast.LENGTH_SHORT);
          toast.show();
      }
docs: Shows a specific toast and cancels a previous one, if existing.
  
  @param text
  The text of the toast, which should be shown, as a {@link String}, or null, if no
  toast should be shown