code: public View getActivityContentView() {
          try {
              return ((Activity) mainActionView.getContext()).getWindow().getDecorView().findViewById(android.R.id.content);
          }
          catch(ClassCastException e) {
              throw new ClassCastException("Please provide an Activity context for this FloatingActionMenu.");
          }
      }
docs: Finds and returns the main content view from the Activity context.
  @return the main content view