private static boolean toggleActionBarHelper(@NonNull final AbstractNavigationBarActivity activity) {
        final ActionBar actionBar = activity.getSupportActionBar();
        if (actionBar == null) {
            return false;
        }
        if (actionBar.isShowing()) {
            actionBar.hide();
            return false;
        } else {
            actionBar.show();
            return true;
        }
    }
use this instead of AbstractBottomNavigationActivity.setContentView for being able to use a action bar toogle
main/src/main/java/cgeo/geocaching/utils/HideActionBarUtils.java