code: private MenuItem addInternal(int group, int id, int categoryOrder, CharSequence title) {
          final int ordering = getOrdering(categoryOrder);
  
          final MenuItemImpl item = new MenuItemImpl(this, group, id, categoryOrder,
                  ordering, title, mDefaultShowAsAction);
  
          if (mCurrentMenuInfo != null) {
              // Pass along the current menu info
              item.setMenuInfo(mCurrentMenuInfo);
          }
  
          mItems.add(findInsertIndex(mItems, ordering), item);
          onItemsChanged(true);
  
          return item;
      }
docs: Adds an item to the menu.  The other add methods funnel to this.