TabBarView  组件中切换页面时，子页面每次均会重新  initState  一次，导致每次都切换页面均会重绘（原地址）

import 'package:flutter/material.dart';
 
class Pages extends StatefulWidget{
  @override
  _PagesState createState() => _PagesState();
}
 
class _PagesState extends State<Pages> with AutomaticKeepAliveClientMixin{
 
  @override
  bool get wantKeepAlive => true; ///see AutomaticKeepAliveClientMixin
 
  @override
  Widget build(BuildContext context) {
    super.build(context); /// see AutomaticKeepAliveClientMixin
    // TODO: implement build
    return Container();
  }
}