直接放源码
import 'package:flutter/gestures.dart'; import 'package:flutter/material.dart'; class FixTabBarView extends StatefulWidget { const FixTabBarView({ Key key, @required this.children, @required this.tabController, @required this.pageController, this.physics, this.dragStartBehavior = DragStartBehavior.start, }) : assert(children != null), assert(dragStartBehavior != null), super(key: key); final TabController tabController; final PageController pageController; final List<Widget> children; final ScrollPhysics physics; final DragStartBehavior dragStartBehavior; @override _FixTabBarViewState createState() => _FixTabBarViewState(); } class _FixTabBarViewState extends State<FixTabBarView> { @override void dispose() { super.dispose(); widget.tabController.dispose(); widget.pageController.dispose(); } @override Widget build(BuildContext context) { return PageView( dragStartBehavior: widget.dragStartBehavior, physics: widget.physics, controller: widget.pageController, children: widget.children, onPageChanged: (index) { widget.tabController.animateTo(index); }, ); } } |
解决方法很简单，用PageView替代TabBarView。TabBarView的问题肯定都遇到过，各种各样的bug就不一一列举了。使用方法只需要把类名从TabBarView改成FixTabBarView，然后传递tabController和pageController到FixTabBarView，再加一个步骤，就是添加TabBar的onTap参数，调用pageController.jumpToPage(index);即可。还要注意你的FixTabBarView的children的State需要with AutomaticKeepAliveClientMixin，demo如下：
import 'package:campsite_flutter/widget/fix_tabbar_view.dart'; import 'package:flutter/material.dart'; void main() { runApp( MaterialApp( home: Scaffold( appBar: AppBar( title: Text("FixTabBarView"), ), body: Test(), ), ), ); } class Test extends StatefulWidget { @override _TestState createState() => _TestState(); } class _TestState extends State<Test> with SingleTickerProviderStateMixin { PageController _pageController; TabController _tabController; List<String> _tabList = ["A", "B", "C"]; @override void initState() { super.initState(); _tabController = TabController(length: _tabList.length, vsync: this); _pageController = PageController(); } @override void dispose() { super.dispose(); _tabController.dispose(); } @override Widget build(BuildContext context) { return Column( children: <Widget>[ TabBar( labelColor: Colors.blue, controller: _tabController, tabs: _tabList.map((text) { return Tab( text: text, ); }).toList(), onTap: (index) { _pageController.jumpToPage(index); }, ), Expanded( child: FixTabBarView( pageController: _pageController, tabController: _tabController, children: _tabList.map((text) { return Page(tab: text); }).toList(), ), ), ], ); } } class Page extends StatefulWidget { final String tab; Page({Key key, this.tab}) : super(key: key); @override _PageState createState() => _PageState(tab: tab); } class _PageState extends State<Page> with AutomaticKeepAliveClientMixin { String tab; _PageState({@required this.tab}); int _count = 0; void add() { setState(() { ++_count; }); } @override void didUpdateWidget(Page oldWidget) { super.didUpdateWidget(oldWidget); } @override void initState() { super.initState(); print("initState $tab $hashCode count=$_count"); } @override Widget build(BuildContext context) { super.build(context); print("build $tab $hashCode count=$_count"); return Scaffold( body: Center( child: Text("$tab $_count"), ), floatingActionButton: FloatingActionButton( onPressed: add, child: Icon(Icons.add), ), ); } @override bool get wantKeepAlive => true; } |
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