code: public void setTopbarVisible(boolean visible) {
      topbar.setVisibility(visible ? View.VISIBLE : View.GONE);
      requestLayout();
    }
docs: Sets the visibility {@link #topbar}, which contains
  the previous month button {@link #buttonPast}, next month button {@link #buttonFuture},
  and the month title {@link #title}.
  
  @param visible Boolean indicating if the topbar is visible