不根据身份验证状态 Flutter 更改屏幕

Question

根据用户是否成功通过身份验证，我正在尝试转到主屏幕或停留在身份验证屏幕上。使用 Firebase 身份验证的 authStateChanges 和流构建器。

我没有收到错误代码，控制台显示

D/FirebaseAuth(21665): Notifying id token listeners about user ( pG6pORODSGMi21fuaoql29hqXZp2 ).
D/FirebaseAuth(21665): Notifying auth state listeners about user ( pG6pORODSGMi21fuaoql29hqXZp2 ).

所以身份验证成功，当我热启动应用程序时，它会进入主屏幕并显示应有的信息。 这是代码

FutureBuilder(
        future: _initialization,
        builder: (context, appsnapShot) {
          return MaterialApp(
            title: 'Flutter Demo',
            theme: ThemeData(
              primarySwatch: Colors.blue,
            ),
            routes: {
              SignupScreen.routeName: (ctx) => SignupScreen(),
              AuthScreen.routeName: (ctx) => AuthScreen(),
              HomeScreen.routeName: (ctx) => HomeScreen(),
              UserPhoneAdds.routeName: (ctx) => UserPhoneAdds(),
              PhoneAddForm.routeName: (ctx) => PhoneAddForm(),
              EditPhoneScreen.routeName: (ctx) => EditPhoneScreen(),
            },
            home: appsnapShot.connectionState != ConnectionState.done
                ? SplashScreen()
                : StreamBuilder(
                    stream: FirebaseAuth.instance.authStateChanges(),
                    builder: (context, snapshot) {
                      if (snapshot.connectionState == ConnectionState.waiting) {
                        return SplashScreen();
                      }
                      if (snapshot.hasData) {
                        return HomeScreen();
                      } else {
                        return AuthScreen();
                      }
                    },
                  ),
          );
        });

仅供参考-这不在课程范围内，并且在来自此的应用程序中正常工作 感谢您的帮助。

Answer 1

authStateChanges 不返回快照，而是返回 User，正如您在官方 documentation 中看到的那样：

FirebaseAuth.instance
  .authStateChanges()
  .listen((User user) {
    if (user == null) {
      print('User is currently signed out!');
    } else {
      print('User is signed in!');
    }
  });

所以你只需检查User 是否为null。