dart – 在flutter中从tab1切换到tab3会产生错误 – 最小颤振App

概述我目前有一个TabBarView.TabBarView有3个选项卡. 第二个选项卡有一个页面,其中还有两个选项卡.现在的问题是我是否直接从tab0切换到tab2.我收到以下错误： flutter: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════ 我目前有一个TabbarVIEw.TabbarVIEw有3个选项卡.
第二个选项卡有一个页面,其中还有两个选项卡.现在的问题是我是否直接从tab0切换到tab2.我收到以下错误：

Flutter: ══╡ EXCEPTION CAUGHT BY WidgetS liBRARY ╞═══════════════════════════════════════════════════════════Flutter: The following assertion was thrown while finalizing the Widget tree:Flutter: 'package:Flutter/src/Widgets/scroll_position.dart': Failed assertion: line 627 pos 12: 'pixels !=Flutter: null': is not true.Flutter:Flutter: Either the assertion indicates an error in the framework itself,or we should provIDe substantiallyFlutter: more information in this error message to help you determine and fix the underlying cause.Flutter: In either case,please report this assertion by filing a BUG on GitHub:Flutter:   https://github.com/Flutter/Flutter/issues/newFlutter:Flutter: When the exception was thrown,this was the stack:Flutter: #2      Scrollposition.dispose (package:Flutter/src/Widgets/scroll_position.dart)Flutter: #3      ScrollpositionWithSingleContext.dispose (package:Flutter/src/Widgets/scroll_position_with_single_context.dart:260:11)Flutter: #4      ScrollableState.dispose (package:Flutter/src/Widgets/scrollable.dart:324:14)Flutter: #5      StatefulElement.unmount (package:Flutter/src/Widgets/framework.dart:3821:12)Flutter: #6      _InactiveElements._unmount (package:Flutter/src/Widgets/framework.dart:1697:13)Flutter: #7      _InactiveElements._unmount.<anonymous closure> (package:Flutter/src/Widgets/framework.dart:1695:7)Flutter: #8      ComponentElement.visitChildren (package:Flutter/src/Widgets/framework.dart:3676:14)Flutter: #9      _InactiveElements._unmount (package:Flutter/src/Widgets/framework.dart:1693:13)

这是应用程序本身

Page : main.dartimport 'package:Flutter/material.dart';import "TabsPage.dart";voID main() => runApp(new MyApp());class MyApp extends StatelessWidget {  // This Widget is the root of your application.  @overrIDe  Widget build(BuildContext context) {    return new MaterialApp(      Title: 'Flutter Demo',theme: new themeData(        primarySwatch: colors.blue,),home: new MyHomePage(Title: 'Flutter Demo Home Page'),);  }}class MyHomePage extends StatefulWidget {  MyHomePage({Key key,this.Title}) : super(key: key);  final String Title;  @overrIDe  _MyHomePageState createState() => new _MyHomePageState();}class _MyHomePageState extends State<MyHomePage>  with SingleTickerProvIDerStateMixin {  TabController _tabController;  var tabbarVIEw;  var bottomNavigationbar;  voID initializeTabs()  {    _tabController = new TabController(vsync: this,length: 3);  }  Widget getBottomNavigationbar() {    bottomNavigationbar = new Material(            child: new Tabbar(controller: _tabController,tabs: <Tab>[              new Tab(text: "PageA" ),new Tab(text: "PageB"),new Tab(text: "PageC"),]));    return bottomNavigationbar;  }  @overrIDe  voID initState() {    super.initState();    initializeTabs();  }  @overrIDe  Widget build(BuildContext context) {    return new Scaffold(      appbar: new Appbar(        Title: new Text("Tabs demo"),automaticallyImplyLeading: false,bottomNavigationbar: getBottomNavigationbar(),//Add the bottom Navigation bar      body:  new TabbarVIEw(controller: _tabController,children: <Widget>[        new Text("PageA"),new Mytest(),new Text("PageC"),]),//The container that will display the pages      );  }}

这是第二页

import 'package:Flutter/material.dart';class MyTest extends StatefulWidget {    Mytest();    @overrIDe    MyTestState createState() => new MyTestState();}    class MyTestState extends State<MyTest> with SingleTickerProvIDerStateMixin,RouteAware {        bool isAlive;        TabController _tabController;        var tabbarVIEw;        MyTestState();        @overrIDe        voID initState() {            super.initState();            _tabController = new TabController(vsync: this,length: 2,initialindex: 1);        }        @overrIDe        voID dispose() {            _tabController.dispose();            super.dispose();        }        @overrIDe        Widget build(BuildContext context) {            var scaffold = Scaffold(                appbar: new Appbar(                    automaticallyImplyLeading: false,bottom: new PreferredSize(                        preferredSize: new Size(200.0,15.0),child: new Container(                            wIDth: 200.0,child: new Tabbar(                                controller: _tabController,tabs: [                                    new Container(                                        child: new Tab(text: 'TabA'),new Container(                                        child: new Tab(text: 'TabB'),],body: new TabbarVIEw(controller: _tabController,children: <Widget>[                    new Text("Hello World in TabA"),new Text("Hello World in TabB"),//The container that will display the pages                );            return scaffold;        }}

如果我从第二页的正文中替换TabbarVIEw,则不会发生此问题

解决方法 我很久以前就报告了这个BUG

https://github.com/flutter/flutter/issues/11267

https://github.com/flutter/flutter/issues/11350

我意识到你不能拥有嵌套的脚手架.如果您嵌套Scaffolds,则行为将变为未定义且不受颤振团队的支持.

重构您的应用程序,以便Scaffold不再嵌套

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