When Flutter achieve TabBarView switching of each page only once initState

When the switch assembly TabBarView page, each subpage will initState once again, lead to switching every time the page will be redrawn as shown below

If you need to enter the page only once in the first   initState  first, followed by re-entering the page no longer   initState  , you need to add the following in the sub-pages

First, in the back of class inheritance plus   with AutomaticKeepAliveClientMixin  

with AutomaticKeepAliveClientMixin

　　

Was then added in the class

@override
bool get wantKeepAlive => true; ///see AutomaticKeepAliveClientMixin

　　

Finally, the added build

super.build(context); /// see AutomaticKeepAliveClientMixin

　　

The complete code is as follows

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();
  }
}

　　

Complete results are as follows, at this time will only execute initState the first time into the page