class HomePageState extends State{

  final topTitles = ['审批单', '机票列表', '客服'];

  final topIcons = ['assets/home/approval.png', 'assets/home/air_ticket.png', 'assets/home/service.png'];

  @override

  Widget build(BuildContext context) {

    // TODO: implement build

    return new Scaffold(

      appBar: AppBar(

        title: Text('首页')

      ),

      body: Column(

        children: <Widget>[

          //顶部

          Row(

            children: topTitles.asMap().keys.map((f)=>
　　　　　　　　　　//f拿到的就是下标：

                Expanded(

                  flex: ,

                  child: Column(

                    children: <Widget>[

                      Image(

                        image: new AssetImage(topIcons[f]),

                        height: , width: ),

                      Text(topTitles[f])

                    ],

                  ),

                )).toList(),

          ),

          //列表

        ],

      ),

    );

  }

  @override

  void initState() {

    // TODO: implement initState

    super.initState();

    print("initStateHome");

  }

}