提供Tab页的窗口视图容器，它有俩个children，一组是用户可以选择指定Tab页的标签，另一组是FrameLayout用来显示该Tab页的内容。个别元素通常控制使用这个容器对象，而不是设置在子元素本身的值。-Tab page window view of the container, it has both children, a group of users can choose to specify Tab page label, another group FrameLayout used to display the contents of the Tab page. Individual elements usually controlled using this container object, instead of setting the value of the sub-element itself.