Flutter 退出 go 重新打开应用后不会登录

Question

我有以下注销代码，只要用户在重新打开应用程序后不尝试注销，它就可以正常工作。 这意味着如果用户登录并使用该应用程序，然后单击注销，该应用程序将返回到登录页面。 但是，如果用户在登录后关闭应用程序，然后重新打开应用程序并单击注销，应用程序将显示主页而不是登录页面。 该应用程序在这种情况下被冻结，应该关闭并重新打开它以再次看到登录页面。

signOut(BuildContext context) async {
  SharedPref.saveLoginSharedPreference(false);
  var databasesPath = await getDatabasesPath();
  String path = join(databasesPath, 'patient.db');
  deleteDatabase(path);
  LocationService().dispose();
  Navigator.pushAndRemoveUntil(context,
      MaterialPageRoute(builder: (context) => const LoginScreen()), (route) => false);
  Phoenix.rebirth(context);
}

总机dart：

Future<void> backgroundHandler(RemoteMessage message) async {


await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
}

late AndroidNotificationChannel channel;

late FlutterLocalNotificationsPlugin  flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();


void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  var messaging = FirebaseMessaging.instance;
  String routeFromMessage = '';
  messaging.getInitialMessage().then((message) {
    if (message != null) {
      routeFromMessage = "/" + message.data["route"];
    }
  });
  await messaging.requestPermission(
    alert: true,
    announcement: false,
    badge: true,
    carPlay: false,
    criticalAlert: false,
    provisional: false,
    sound: true,
  );

  LocationService().getListener()?.resume();
  FirebaseMessaging.onBackgroundMessage(backgroundHandler);

  if (!kIsWeb) {
    channel = const AndroidNotificationChannel(
        'high_importance_channel', 'High Importance Notifications',
        importance: Importance.high);

    await flutterLocalNotificationsPlugin
        .resolvePlatformSpecificImplementation<
            AndroidFlutterLocalNotificationsPlugin>()
        ?.createNotificationChannel(channel);

    await messaging.setForegroundNotificationPresentationOptions(
      alert: true,
      badge: true,
      sound: true,
    );
  }

  if (defaultTargetPlatform == TargetPlatform.android) {
    messaging.getToken().then((newToken) {
      SharedPref.saveFCMToken(newToken);
    });
  } else if (defaultTargetPlatform == TargetPlatform.iOS) {
    messaging.requestPermission(alert: true, sound: true);
    await messaging.setForegroundNotificationPresentationOptions(
      alert: true,
      badge: true,
      sound: true,
    );
    messaging.getToken().then((newToken) {
      SharedPref.saveFCMToken(newToken);
    });
  }

  bool? isLoggedIn = await SharedPref.getUserLoginSharedPrefernces();
  isLoggedIn ??= false;
  String route = '';
  if (isLoggedIn && routeFromMessage != '') {
    route = routeFromMessage;
  } else {
    route = isLoggedIn ? '/' : '/loginScreen';
  }

  runApp(Phoenix(
      child: MyApp(
        homepage: route,
        isLoggedIn: isLoggedIn,
      )));
}

class MyApp extends StatelessWidget {
  const MyApp({
    Key? key,
    required this.homepage,
    required this.isLoggedIn,
  }) : super(key: key);
  final bool? isLoggedIn;
  final String homepage;

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'My Main',
      debugShowCheckedModeBanner: false,
      //theme for all screens
      theme: ThemeData(
        primarySwatch: Colors.blue,
        primaryColor: Colors.blue[100],
      ),
      initialRoute: homepage,
      //all possible routes within the app
      home: PushMessaging(
          isLoggedIn: isLoggedIn,
          homepage: homepage,
          title: "Portal"),
      routes: {
        '/questionnairePushNotificationRoot': (context) =>
        const QuestionnaireRoot(),
        '/singleChoiceNew': (context) => const SelectionWindow(),
        '/exercisePrescriptionPage': (context) =>
        const ExercisePrescriptionHome(),
        '/multipleChoice': (context) => const MultipleChoice(),
        '/scale': (context) => const Scale(),
        '/textfield': (context) => const FreeTextfield(),
        '/endScreen': (context) => const EndScreen(),
        '/loginScreen': (context) => const LoginScreen(),
        '/registerScreen': (context) => const RegisterScreen(),
        '/forgotPassword': (context) => const ForgotPassword(),
        '/training': (context) => const Training(),
        '/riskFactors': (context) => const RiskFactors(),
        '/chat': (context) => const ChatDetailPage(),
      },
    );
  }
}

Answer 1

如果用户未登录，您应该让您的应用程序自动重定向到登录屏幕，而不是手动尝试处理登录屏幕的导航。由于您已经在使用 Firebase，我建议使用firebase_auth进行身份验证，它附带自己的身份验证 state Stream : FirebaseAuth.instance.authStateChanges() 。 Firebase 还会在应用程序启动之间自动保留身份验证 state。 如果您想改用自己的身份验证系统，只需使用StreamController创建您自己的 stream 即可。

注意：看起来您正在使用带有命名路由的 Navigator 1.0。 但是，如果有读者使用Navigator 2.0，这个方法就不行了。

将整个应用程序包装在StreamBuilder中并收听FirebaseAuth.instance.authStateChanges() ：

// In the build method of MyApp:
Widget build(BuildContext context) {
  return MaterialApp(
    title: 'My Main',
    home: StreamBuilder<User?>(
      // Here's where you listen to changes in authentication state.
      stream: FirebaseAuth.instance.authStateChanges(),
      builder: (context, snapshot) {
        // If there's no user data in the stream, show the login screen.
        if (!snapshot.hasData) return const LoginScreen();
        
        // Otherwise show the rest of your app.
        return PushMessaging(
          isLoggedIn: isLoggedIn,
          homepage: homepage,
          title: "Portal",
        );
      },
    ),
  );
}

这将在用户登录时自动显示您的应用程序，并在用户注销时自动切换到您的登录屏幕。 然后为您退出 function：

signOut(...) {
  // Do whatever else you want to do...
  // Then tell firebase you're signing out.
  FirebaseAuth.instance.signOut();
}

Answer 2

我按如下方式更改了注销，现在可以使用了：

signOut(BuildContext context) async {
  SharedPref.saveLoginSharedPreference(false);
  var databasesPath = await getDatabasesPath();
  String path = join(databasesPath, 'patient.db');
  deleteDatabase(path);
  LocationService().dispose();
  Navigator.of(context)
      .push(MaterialPageRoute(builder: (context) => const LoginScreen()));
}