import ''package:flutter/material.dart'';

class AppBarDemoPage extends StatelessWidget {
  const AppBarDemoPage({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length:2 ,
      child: Scaffold(
          appBar: AppBar(
            title:Text("AppBarDemoPage"), 
            // backgroundColor: Colors.red, 
            centerTitle:true,
           
            bottom: TabBar(
              tabs: <Widget>[
                Tab(text: "热门"),
                Tab(text: "推荐")
              ],
            ),


          ),
          body: TabBarView(
            children: <Widget>[
              ListView(
                children: <Widget>[
                  ListTile(
                    title:Text("第一个tab")
                  ),
                  ListTile(
                    title:Text("第一个tab")
                  ),
                  ListTile(
                    title:Text("第一个tab")
                  )
                ],
              ),
               ListView(
                children: <Widget>[
                  ListTile(
                    title:Text("第二个tab")
                  ),
                  ListTile(
                    title:Text("第二个tab")
                  ),
                  ListTile(
                    title:Text("第二个tab")
                  )
                ],
              )
            ],
          ),
        ),
    );
  }
}

import ''package:flutter/material.dart'';

class CategoryPage extends StatefulWidget {
  CategoryPage({Key key}) : super(key: key);

  _CategoryPageState createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length: 4,
      child: Scaffold(
        appBar: AppBar(

          backgroundColor: Colors.black26,
          title: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Expanded(
                  child:TabBar(
                    indicatorColor:Colors.blue,
                    labelColor:Colors.blue,
                    unselectedLabelColor: Colors.white,
                    indicatorSize:TabBarIndicatorSize.label ,
                    
                    tabs: <Widget>[
                      Tab(text: "热销"),
                      Tab(text: "推荐"),
                      Tab(text: "热门"),
                      Tab(text: "视频")
                    ],
               ) ,
              )
            ],
          ),
          
        ),
        body:TabBarView(
          children: <Widget>[

            ListView(
                children: <Widget>[
                  ListTile(
                    title:Text("第一个tab")
                  ),
                  ListTile(
                    title:Text("第一个tab")
                  ),
                  ListTile(
                    title:Text("第一个tab")
                  )
                ],
              ),
            ListView(
                children: <Widget>[
                  ListTile(
                    title:Text("第二个tab")
                  ),
                  ListTile(
                    title:Text("第二个tab")
                  ),
                  ListTile(
                    title:Text("第二个tab")
                  )
                ],
              ),
              ListView(
                children: <Widget>[
                  ListTile(
                    title:Text("第3个tab")
                  ),
                  ListTile(
                    title:Text("第3个tab")
                  ),
                  ListTile(
                    title:Text("第一个tab")
                  )
                ],
              ),
            ListView(
                children: <Widget>[
                  ListTile(
                    title:Text("第4个tab")
                  ),
                  ListTile(
                    title:Text("第二个tab")
                  ),
                  ListTile(
                    title:Text("第二个tab")
                  )
                ],
              )
          ],
        )
      ),
    );
  }
}

import ''package:flutter/material.dart'';

class TabBarControllerPage extends StatefulWidget {
  TabBarControllerPage({Key key}) : super(key: key);

  _TabBarControllerPageState createState() => _TabBarControllerPageState();
}

class _TabBarControllerPageState extends State<TabBarControllerPage> with SingleTickerProviderStateMixin {

  TabController _tabController;

  @override
  void dispose() {   //生命周期函数
    // TODO: implement dispose
    super.dispose();
    _tabController.dispose();
  }

  @override
  void initState() {   //生命周期函数
    // TODO: implement initState
    super.initState();
    _tabController=new TabController(
      vsync: this,
      length: 2
    );
    //可以监听一些方法
    // _tabController.addListener((){

    //   print(_tabController.index);     
    // });
  }  


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("TabBarControllerPage"),
        bottom: TabBar(
          controller: this._tabController,  //注意
          tabs: <Widget>[
            Tab(text:"热销"),
            Tab(text:"推荐"),
          ],
        ),
      ),
      body: TabBarView(
        controller: this._tabController,  //注意
        children: <Widget>[
          Center(child: Text("热销")),
          Center(child: Text("推荐"))
          
        ],
      ),
    );
  }
}