尝试根据我的应用程序中的用户状态(登录或未登录)进行重定向,但它不会像我想要的那样工作,因为我不确定如何在方法中获取 BuildContext。
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:t2/helpers/currentuser.dart';
import 'screens/dashboard.dart';
import 'screens/login.dart';
void main() => runApp(new MyApp());
CurrentUser user = new CurrentUser();
Future checkActiveUser() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
user.usr = prefs.get('usr');
user.pwd = prefs.get('pwd');
if (user.usr.length == 0 && user.pwd.length == 0) {
user.isLoggedIn = false;
Navigator.of(x).pushNamedAndRemoveUntil('/dashboard', (Route<dynamic> route) => false);
} else {
// Send to login screen
user.isLoggedIn = false;
Navigator.of(x).pushNamedAndRemoveUntil('/login', (Route<dynamic> route) => false);
}
return user.isLoggedIn;
/*
// How to read/write to local storage
int counter = (prefs.getInt('counter') ?? 0) + 1;
print('Pressed $counter times.');
prefs.setInt('counter', counter);
*/
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Flutter Demo',
theme: new ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or press Run > Flutter Hot Reload in IntelliJ). Notice that the
// counter didn't reset back to zero; the application is not restarted.
primarySwatch: Colors.blue,
),
home: new MyHomePage(),
routes: <String, WidgetBuilder>{
'/dashboard': (BuildContext context) => new Dashboard(),
'/login': (BuildContext context) => new Login()
});
}
}
class MyHomePage extends StatelessWidget {
var isLoggedIn = checkActiveUser();
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text('Demo Building'),
),
body: new Container(
child: new Center(
child: new Column(
children: <Widget>[new Text('DASHBOARD')],
),
)));
}
}
如果您有不同方法的建议,我会洗耳恭听!我基本上想在应用程序加载时运行此检查并相应地重定向。
问候,鲍勃
更新代码:尝试了 Hadrien 的建议,并且更接近了一步。它现在运行并且我获得了联系人访问权限,但是出现以下错误:
'使用不包含导航器的上下文请求导航器操作。用于从 Navigator 推送或弹出路由的上下文必须是作为 Navigator 小部件后代的小部件的上下文。'
这是更新后的代码:
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:t2/helpers/currentuser.dart';
import 'screens/dashboard.dart';
import 'screens/login.dart';
void main() => runApp(new MyApp());
CurrentUser user = new CurrentUser();
checkActiveUser(BuildContext context) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
try {
user.usr = prefs.get('usr');
user.pwd = prefs.get('pwd');
if (user.usr.length == 0 && user.usr.length == 0) {
user.isLoggedIn = false;
Navigator
.of(context)
.pushNamedAndRemoveUntil('/dashboard', (Route<dynamic> route) => false);
} else {
throw new Exception('No user data found');
}
} catch (e) {
// Send to login screen
user.isLoggedIn = false;
Navigator
.of(context)
.pushNamedAndRemoveUntil('/login', (Route<dynamic> route) => false);
}
/*
// How to read/write to local storage
int counter = (prefs.getInt('counter') ?? 0) + 1;
print('Pressed $counter times.');
prefs.setInt('counter', counter);
*/
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => new _MyAppState();
}
class _MyAppState extends State<MyApp> {
void initState() {
super.initState();
checkActiveUser(context);
}
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Welcome to Flutter',
home: new Scaffold(
appBar: new AppBar(
title: new Text('CADSYS'),
),
body: new Center(
child: new Text('Loading...'),
),
),
routes: <String, WidgetBuilder> {
'/dashboard': (BuildContext context) => new Dashboard(),
'/login': (BuildContext context) => new Login()
},
);
}
}
最佳答案
我可能会做一些不同的事情...而不是在函数中推送路由,在 StatefulWidget
中设置登录状态,然后设置 body
基于
正文:user.isLoggedIn ?新仪表板():新登录(),
然后在代码的其他地方,您需要检查事件用户并执行 setState((){ user.isLoggedIn = true; });
(或 false)。
当登录状态发生变化时,您的 View 将自动更新为新的 Widget。
关于dart - flutter:根据不同的状态路由到不同的页面,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49359706/