Flutter:从小部件重定向到另一个页面

Question

我正在尝试实现一个注销页面。因此，当用户点击导航中的注销按钮时，会调用以下代码：

Class Logout extends StatelessWidget {
@override
Widget build(BuildContext context) {
final provider = Provider.of<SignInProvider>(context, listen: true);
Future.delayed(Duration(seconds: 5), () async {
provider.isLoggedIn = false;
provider.notifyListeners();
Navigator.pushReplacement(
context, new MaterialPageRoute(builder: (context) => LoginGate()));
});
return Center(child: CircularProgressIndicator());
}
}

我得到以下错误：

The following assertion was thrown building MainScreen(dirty, dependencies: [_InheritedProviderScope<SelectedIndex?>, _InheritedProviderScope<SignInProvider?>], state: _MainScreenState#6a8ce):
setState() or markNeedsBuild() called during build.

我试着增加延迟，希望这能解决问题，但无济于事。如果您能帮我处理这个问题，我将不胜感激。

使用NavigationRail 显示注销按钮

const NavigationRailDestination(
icon: Icon(Icons.logout),
label: Text('Logout'),
),

Logout小部件使用以下方法调用：

child: Row(
children: [
NavigationRailExample(),
const VerticalDivider(thickness: 1, width: 1),
Expanded(
child: screenSwitch[providerSelectedIndex.selectedIndex],
)
],
),
List<Widget> screenSwitch = [
HomeScreen(),
Screen1(),
Screen2(),
Screen3(),
Screen4(),
Screen5(),
Screen6(),
Logout(),
];

Answer 1

您在构建方法中调用异步函数是错误的。试试这个：

class Logout extends StatelessWidget {
@override
Widget build(BuildContext context) {
return FutureBuilder(
future: doLogOut(context),
builder: (context, snapshot) {
return Center(child: CircularProgressIndicator());
},
);
}
Future<void> doLogOut(BuildContext context) async {
final provider = Provider.of<SignInProvider>(context, listen: true);
await Future.delayed(Duration(seconds: 5), () async {
provider.isLoggedIn = false;
provider.notifyListeners();
Navigator.pushReplacement(
context, new MaterialPageRoute(builder: (context) => LoginGate()));
});
}
}