0

在 2019 年，我设法检查了用户是否登录了该应用程序。不幸的是，从那以后发生了很多变化。我尝试搜索有关 FlutterFire 的教程和指南。但是，我找不到任何东西。我对stream,future和感到很困惑provider。我也不知道他们之间的区别。

我的旧代码（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);
    }
  }
}

如何检查用户是否登录？预先感谢您的帮助。

4

2 回答 2

0

创建一个全局 firebase 用户实例，并在您的第一个屏幕（如启动画面）上检查当前用户是否为空，然后根据结果导航到您选择的屏幕。这是我的代码，您可以稍微更改一下并尝试。

  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;
}
于 2020-11-26T07:15:43.740 回答
0

这适用于FlutterFire！

Firebase Auth 使您能够通过Stream. 一旦被调用，它会stream提供用户当前身份验证状态的即时事件，然后在身份验证状态更改时提供后续事件。要订阅这些更改，请authStateChanges()在您的 FirebaseAuth 实例上调用该方法：

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();
            }
          },
        )
    );
  }
}
于 2020-11-26T07:32:26.520 回答