![](/img/trans.png)
[英]How to check user is logged in or not with firebase for web App in flutter?
[英]How to check whether there is a user logged in the app or not
在 2019 年,我設法檢查了用戶是否登錄了該應用程序。 不幸的是,從那以后發生了很多變化。 我嘗試搜索有關 FlutterFire 的教程和指南。 但是,我找不到任何東西。 我對stream
、 future
和provider
感到很困惑。 我也不知道他們之間的區別。
我的舊代碼(不再起作用):
Future main() async {
runApp(
ChangeNotifierProvider<AuthService>(
child: MyApp(),
create: (BuildContext context) {
return AuthService();
},
),
);
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp, DeviceOrientation.portraitUp]);
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'TestApp',
theme: ThemeData(primarySwatch: Colors.blue),
home: FutureBuilder<FirebaseUser>(
future: Provider.of<AuthService>(context).getUser(),
builder: (context, AsyncSnapshot<FirebaseUser> snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
// log error to console
if (snapshot.error != null) {
print("error");
return Text(snapshot.error.toString());
}
// redirect to the proper page
return snapshot.hasData ? HomePage() : LoginPage();
} else {
// show loading indicator
return LoadingCircle();
}
},
),
);
}
}
class AuthService with ChangeNotifier {
final FirebaseAuth _auth = FirebaseAuth.instance;
Future<FirebaseUser> getUser() {
return _auth.currentUser();
}
Future logout() async {
var result = FirebaseAuth.instance.signOut();
notifyListeners();
return result;
}
Future<FirebaseUser> loginUser({String email, String password}) async {
try {
var result = await FirebaseAuth.instance
.signInWithEmailAndPassword(email: email, password: password);
notifyListeners();
return result.user;
} catch (e) {
throw new AuthException(e.code, e.message);
}
}
}
如何檢查用戶是否登錄? 預先感謝您的幫助。
創建一個全局 firebase 用戶實例,並在您的第一個屏幕上(如在初始屏幕上)檢查當前用戶是否為 null,然后根據結果導航到您選擇的屏幕。 這是我的代碼,您可以稍微更改一下並嘗試。
Future<void> tryAutoLogin() async {
firebaseUser = firebaseAuth.currentUser;
if (firebaseUser == null) return;
Response<AppUser> userDataResponse =
await DatabaseInterface.getUserData(firebaseUser?.uid);
if (userDataResponse.success) {
appUser = userDataResponse.data;
await appUser?.cacheAppUserData();
} else
return;
}
這適用於FlutterFire !
Firebase Auth 使您能夠通過 Stream 實時訂閱此
Stream
。 一旦調用,stream
提供用戶當前身份驗證 state 的即時事件,然后在身份驗證 state 更改時提供后續事件。 要訂閱這些更改,請在 FirebaseAuth 實例上調用authStateChanges()
方法:
import 'package:firebase_auth/firebase_auth.dart' as auth;
import 'package:flutter/material.dart';
import 'menu.dart';
import 'login.dart';
import 'dart:async';
import 'package:flutter/services.dart';
import 'package:firebase_core/firebase_core.dart';
Future main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(
MyApp()
);
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp, DeviceOrientation.portraitUp]);
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'TestApp',
theme: ThemeData(primarySwatch: Colors.blue),
home:
StreamBuilder<auth.User>(
stream: auth.FirebaseAuth.instance.authStateChanges(),
builder: (BuildContext context, AsyncSnapshot<auth.User> snapshot) {
if(snapshot.hasData) {
print("data exists");
return HomePage();
}
else {
return LoginPage();
}
},
)
);
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.