@override
  Widget build(BuildContext context) {
// TODO: implement build
return MaterialApp(
  home: DefaultTabController(length: 3,
      child: Scaffold(
        appBar: AppBar(
          title: Text("App Bar"),
          bottom: TabBar(
            tabs:
            [
              Tab(icon: Icon(Icons.account_circle)),
              Tab(icon: Icon(Icons.ac_unit)),
              Tab(icon: Icon(Icons.print))
            ])),
      drawer: Drawer( child: Column(
        children: <Widget>
        [
          ListTile(
            leading: Icon(Icons.ac_unit),
            title: Text("AC UNIT"),
            onTap: ()
            {
              Navigator.pop(context);
            },
          ),
          ListTile(
            leading: Icon(Icons.message),
            title: Text("Message"),
          ),
          ListTile(
            leading: Icon(Icons.print),
            title: Text("PRINT"),
          )
        ],
      ),),

      body: TabBarView(children:<Widget>
      [
        Icon(Icons.directions_bike),
        new SecondWidget(title: "Second widget"),
        new ThirdWidget()
      ]))));

class ThirdWidget extends StatefulWidget
{
  @override
  _ThirdWidgetState createState() => _ThirdWidgetState();}

class _ThirdWidgetState extends State<ThirdWidget>
{
  @override
  Widget build(BuildContext context) {
    return CustomScrollView(
      slivers: <Widget>
      [
        SliverAppBar(
          pinned: false,
          expandedHeight: 150,
          flexibleSpace: FlexibleSpaceBar(title: Text("Epic Sliver"))
    )],);}}