| actionName | Name of the item. This name will be displayed in the drop-down menu. |
| action | 用户在菜单中选择此项目时要执行的回调。 |
| actionStatusCallback | 确定项目状态要执行的回调。 |
| atIndex | 应插入项目的索引。 |
| userData | An object that will be stored in the userData property of the MenuAction item. This object is accessible through the action callback. |
Add an item that will execute an action in the drop-down menu. The item is added at the end of the specified index in the list.