1 CupertinoTabScaffold
标签式iOS应用程序的结构。将选项卡栏放在内容选项卡之上
2 构造函数
CupertinoTabScaffold({
    Key key,
    @required this.tabBar,
    @required this.tabBuilder,
    this.controller,
    this.backgroundColor,
    this.resizeToAvoidBottomInset = true,
})3 常用属性
3.1 tabBar:底部选项卡
 tabBar: CupertinoTabBar(),3.2 tabBuilder:选项卡内容
tabBuilder: (context, index) {},3.3 backgroundColor:背景色
backgroundColor: Color(0xFFfafcff),正文完