/** Called when a menu item is selected. */
 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
   super.onOptionsItemSelected(item);
   switch (item.getItemId()) {
     case MEN_NEXT_PAGE:
       {
         nextPage();
         break;
       }
     case MEN_PREV_PAGE:
       {
         prevPage();
         break;
       }
     case MEN_GOTO_PAGE:
       {
         gotoPage();
         break;
       }
     case MEN_ZOOM_IN:
       {
         zoomIn();
         break;
       }
     case MEN_ZOOM_OUT:
       {
         zoomOut();
         break;
       }
     case MEN_BACK:
       {
         finish();
         break;
       }
     case MEN_CLEANUP:
       {
         HardReference.cleanup();
         break;
       }
   }
   return true;
 }