我在由 PageController 管理的 PageView 中有一系列有状态的小部件。我正在使用 pageController.jumpToPage(index)
来切换页面。切换页面时,小部件中的所有状态似乎都丢失了,就好像它是从头开始重新创建的。我曾尝试在 PageController 中使用 keepPage: true
但这似乎没有任何效果。这是 PageView 的预期行为还是我做错了什么?任何建议表示赞赏,谢谢!
最佳答案
与 AutomaticKeepAliveClientMixin 一起使用到您的子页面。
然后@override bool get wantKeepAlive => true; 这是一个示例
import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
@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> {
@override
Widget build(BuildContext context) {
return DefaultTabController(
length: 4,
child: new Scaffold(
appBar: new AppBar(
bottom: new TabBar(
tabs: [
new Tab(icon: new Icon(Icons.directions_car)),
new Tab(icon: new Icon(Icons.directions_transit)),
new Tab(icon: new Icon(Icons.directions_bike)),
new Tab(
icon: new Icon(Icons.airplanemode_active),
)
],
),
),
body: new TabBarView(children: [
new OnePage(color: Colors.black,),
new OnePage(color: Colors.green,),
new OnePage(color: Colors.red,),
new OnePage(color: Colors.blue,),
]),
),
);
}
}
class OnePage extends StatefulWidget {
final Color color;
const OnePage({Key key, this.color}) : super(key: key);
@override
_OnePageState createState() => new _OnePageState();
}
class _OnePageState extends State<OnePage> with AutomaticKeepAliveClientMixin<OnePage> {
@override
Widget build(BuildContext context) {
super.build(context);
return new SizedBox.expand(
child: new ListView.builder(
itemCount: 100,
itemBuilder: (context, index) {
return new Padding(
padding: const EdgeInsets.all(10.0),
child: new Text(
'$index',
style: new TextStyle(color: widget.color),
),
);
},
),
);
}
@override
bool get wantKeepAlive => true;
}
https://stackoverflow.com/questions/45944777/