code: private OnClickListener createFloatingActionButtonListener() {
          return new OnClickListener() {
  
              @Override
              public void onClick(final View v) {
                  Toast toast =
                          Toast.makeText(MainActivity.this, R.string.floating_action_button_toast,
                                  Toast.LENGTH_SHORT);
                  toast.show();
              }
  
          };
      }
docs: Creates and returns a listener, which allows to show a toast when a floating action button
  has been clicked.
  
  @return The listener, which has been created, as an instance of the type {@link
  OnClickListener}