Question

我的应用有两个标签，切换标签不会保持其状态。我在网上搜索，发现将AutomaticKeepAliveClientMixin与wantKeepAlive和true一起使用super.build(context)。我完全按照网络和stackoverflow上其他用户的指示进行了操作，但是问题仍然存在。这是我的代码：

void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> with AutomaticKeepAliveClientMixin{
@override
bool get wantKeepAlive => true;

@override
Widget build(BuildContext context) {
super.build(context);
return MaterialApp(
  title: 'Flutter GridView',
  debugShowCheckedModeBanner: false,
  theme: ThemeData(
    primaryColor: Colors.blue,
    accentColor: Colors.white,
  ),
  home: DefaultTabController(
    length: 2,
          child: Scaffold(
      drawer: Drawer(),
      backgroundColor: Colors.blueAccent,
      appBar: AppBar(
        backgroundColor: Colors.blueAccent,
        title: Text('AIO'),
        bottom: TabBar(
          tabs: <Widget>[
            Tab(icon: Icon(Icons.search)),
            Tab(icon: Icon(Icons.favorite)),
          ],
        ),
      ),
      body: TabBarView(
        children: <Widget>[
          gridView,
          SecondPage(),
        ],
      ),
    ),
  ),
);
}}

Answer 1

使用PageStorage，PageStorageBucket和PageStorageKey。

创建PageStorageBucket的实例字段，用PageStorage包装TabBarView，然后将PageStorageKey添加到GridView。

class _MyAppState extends State<MyApp> {
  final PageStorageBucket bucket = PageStorageBucket();
  //...

  body: PageStorage(
    bucket: bucket,
    child: TabBarView(
      children: <Widget>[
        gridView, // add to GridView(key: PageStorageKey('MyGridViewKey'), //...
        SecondPage(),
      ],
    ),
  ),
  //...

即使在使用AutomaticKeepAliveClientMixin和super.build（context）后切换标签时，Flutter TabBar也不会保持状态

1 个答案: