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我有一个场景,其中我根据将用户重定向到 HomePage 或 LandingPage 的值检查 SharePreferences 的值。我不确定我哪里错了?但我在下面收到此错误:我想它没有正确获取上下文,不知道如何获取它?
Unhandled Exception: Navigator operation requested with a context that does not include a Navigator. E/flutter (11533): The context used to push or pop routes from the Navigator must be that of a widget that is a descendant of a Navigator widget.
这是我的代码:
import 'package:credit/src/pages/landing.dart';
import 'package:flutter/material.dart';
import 'package:credit/src/pages/credit/home.dart';
import 'package:shared_preferences/shared_preferences.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
MyApp({Key key}) : super(key: key);
_LoadingPageState createState() => _LoadingPageState();
}
class _LoadingPageState extends State<MyApp> {
@override
void initState() {
super.initState();
getUserStatus().then((userStatus) {
if (userStatus == null) {
Navigator.of(context)
.push(MaterialPageRoute<Null>(builder: (BuildContext context) {
return LandingPage();
}));
} else {
Navigator.of(context)
.push(MaterialPageRoute<Null>(builder: (BuildContext context) {
return HomePage();
}));
}
});
}
@override
Widget build(BuildContext context) {
return Container(
child: Center(
child: CircularProgressIndicator(),
));
}
}
Future<String> getUserStatus() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
String userStatus = prefs.getString('userstatus');
print("==On Load Check ==");
print(userStatus);
return userStatus;
}
最佳答案
当您调用 Navigator.of(context)
时,框架会在附加到提供的 context
的小部件树中上升,并尝试找到最近的 Navigator
.
您显示的小部件树没有,因此您需要在小部件树中包含Navigator
。
最简单的选择是将 MaterialApp
与作为 home
传递的小部件一起使用。 MaterialApp
正在其内部创建导航器。 (CupertinoApp
也这样做)
原始示例的更新代码:
import 'package:credit/src/pages/landing.dart';
import 'package:flutter/material.dart';
import 'package:credit/src/pages/credit/home.dart';
import 'package:shared_preferences/shared_preferences.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
MyApp({Key key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
home: LoadingPage(),
);
}
}
class LoadingPage extends StatefulWidget {
LoadingPage({Key key}) : super(key: key);
_LoadingPageState createState() => _LoadingPageState();
}
class _LoadingPageState extends State<LoadingPage> { // note type update
@override
void initState() {
super.initState();
getUserStatus().then((userStatus) {
if (userStatus == null) {
Navigator.of(context)
.push(MaterialPageRoute<Null>(builder: (BuildContext context) {
return LandingPage();
}));
} else {
Navigator.of(context)
.push(MaterialPageRoute<Null>(builder: (BuildContext context) {
return HomePage();
}));
}
});
}
@override
Widget build(BuildContext context) {
return Container(
child: Center(
child: CircularProgressIndicator(),
));
}
}
Future<String> getUserStatus() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
String userStatus = prefs.getString('userstatus');
print("==On Load Check ==");
print(userStatus);
return userStatus;
}
关于 flutter : Navigator operation requested with a context that does not include a Navigator,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57241008/
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