tabBarController

import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'bicycleCharge.dart';
import 'carCharg.dart';

class TabsPage extends StatefulWidget{
  @override
  _TabsPageState createState() => new _TabsPageState();
}

class _TabsPageState extends State<TabsPage> with SingleTickerProviderStateMixin{
  TabController _tabController;

  //①初始化，一加载便会触发该方法
  void initState(){
    super.initState();
    _tabController = new TabController(
      vsync: this,
      length: 2,
    );
  }


  @override
  Widget build(BuildContext context){
    //初始化
    ScreenUtil.instance = ScreenUtil( 750, height: 1334)..init(context);
    return DefaultTabController(
      length: 2,
      child: Scaffold(
        appBar: appBar(),
        body: Stack(
          children: <Widget>[
            TabBarView(
              controller: this._tabController,//③
              children: <Widget>[ 
                ElectricBicycle(),
                CarCharge(),
              ],
            ),
          ],
        ),
        drawer: Container(
          padding: EdgeInsets.only(left: 80, right: 10),
          color: Colors.white,
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text('个人中心')
            ],
          ),
        ),
      ),
    );
  }

  // appBar
  Widget appBar(){
    return AppBar(
       centerTitle: true,
        leading: IconButton(
          icon: Icon(
            Icons.person, 
            color: Color.fromRGBO(46, 48, 56, 1),
          ),
          onPressed: (){
            debugPrint('ddddd');
            Scaffold.of(context).openDrawer();
          },
        ),
        title: Container(
          child:  Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text(
                'XXXXXX',
                style: TextStyle(
                  color: Colors.black,
                ),
                textAlign: TextAlign.right,
              ),
              IconButton(
                alignment: Alignment.centerLeft,
                icon: Icon(
                  Icons.arrow_drop_down, 
                  color: Color.fromRGBO(46, 48, 56, 1),
                ),
                onPressed: (){
                  debugPrint('down');
                },
              ),
            ],
          ),
        ),
        actions: <Widget>[
          Container(
             ScreenUtil.getInstance().setWidth(60),
            height: ScreenUtil.getInstance().setHeight(60),
            child: IconButton(
              icon: Image.asset('assets/icons/icon_title_msg.png'),
              onPressed: (){
                debugPrint('down');
              },
            ),
          ),
        ],
        elevation: 0,
        bottom: TabBar(
          controller: this._tabController,//②
          isScrollable: true,
          indicator: const BoxDecoration(),
          unselectedLabelColor: Color.fromRGBO(46, 48, 56, 1),
          indicatorColor: Colors.black54,
          indicatorSize: TabBarIndicatorSize.label,
          // indicatorWeight: 1.0,
          labelColor: Colors.black,
          tabs: <Widget>[
            Tab(
              child: Text(
                'tabA',
                style: TextStyle(
                  fontSize: ScreenUtil.getInstance().setSp(38)
                ),
              ),
            ),
            Tab(
              child: Text(
                'tabB',
                style: TextStyle(
                  fontSize: ScreenUtil.getInstance().setSp(38)
                ),
              ),
            ),
          ],
        ),
        backgroundColor: Colors.white,
      );
  }
}