public boolean onBackPressed() {
   if (mLayout != null && (mLayout.isPanelExpanded() || mLayout.isPanelDragging())) {
     mLayout.setAnchorPoint(1.0f);
     mLayout.collapsePanel();
     return true;
   } else {
     if (mUnfoldableView != null
         && (mUnfoldableView.isUnfolded() || mUnfoldableView.isUnfolding())) {
       mUnfoldableView.foldBack();
       return true;
     }
   }
   return false;
 }