访问 BuildContext 以从推送通知服务进行导航 (Flutter)

Question

我正在努力了解如何在颤动中选择通知时从推送通知类进行导航。我需要访问 BuildContext 或以某种方式找到一种方法来告诉我的应用程序在没有它的情况下进行导航。

我的代码如下所示：

main.dart

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  await PushNotificationService().setupInteractedMessage();
  runApp(const MyApp());
}

Future awaitDeepLink() async {
  StreamSubscription _sub;
  try {
    await getInitialLink();
    _sub = uriLinkStream.listen((Uri uri) {
      runApp(MyApp(uri: uri));
    }, onError: (err) {

    });
  } on PlatformException {
    print("PlatformException");
  } on Exception {
    print('Exception thrown');
  }
}

class MyApp extends StatelessWidget {
  final Uri uri;

  static final FirebaseAnalytics analytics = FirebaseAnalytics.instance;

  const MyApp({Key key, this.uri}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return OverlaySupport(
      child: GestureDetector(
        behavior: HitTestBehavior.opaque,
        onTap: () {
          FocusScopeNode currentFocus = FocusScope.of(context);

          if (!currentFocus.hasPrimaryFocus &&
              currentFocus.focusedChild != null) {
            FocusManager.instance.primaryFocus.unfocus();
          }
        },
        child: MaterialApp(
          debugShowCheckedModeBanner: false,
          theme: buildThemeData(),
          home: CheckAuth(uri: uri),
        ),
      ),
    );
  }
}

PushNotificationService.dart

class PushNotificationService {
  Future<void> setupInteractedMessage() async {
    RemoteMessage initialMessage =
        await FirebaseMessaging.instance.getInitialMessage();
    String token = await FirebaseMessaging.instance.getToken();

    var storage = const FlutterSecureStorage();
    storage.write(key: "fcm_token", value: token);

    if (initialMessage != null) {
      print(initialMessage.data['type']);
    }

    FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
      print("message opened app:" + message.toString());
    });

    await enableIOSNotifications();
    await registerNotificationListeners();
  }

  registerNotificationListeners() async {
    AndroidNotificationChannel channel = androidNotificationChannel();

    final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
        FlutterLocalNotificationsPlugin();

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

    var androidSettings =
        const AndroidInitializationSettings('@mipmap/ic_launcher');

    var iOSSettings = const IOSInitializationSettings(
      requestSoundPermission: false,
      requestBadgePermission: false,
      requestAlertPermission: false,
    );

    var initSettings = InitializationSettings(
      android: androidSettings,
      iOS: iOSSettings,
    );

    flutterLocalNotificationsPlugin.initialize(
      initSettings,
      onSelectNotification: onSelectNotification,
    );

    FirebaseMessaging.onMessage.listen((RemoteMessage message) {
      RemoteNotification notification = message.notification;
      AndroidNotification android = message.notification.android;

      if (notification != null && android != null) {
        flutterLocalNotificationsPlugin.show(
          notification.hashCode,
          notification.title,
          notification.body,
          NotificationDetails(
            android: AndroidNotificationDetails(
              channel.id,
              channel.name,
              icon: android.smallIcon,
              playSound: true,
            ),
          ),
          payload: json.encode(message.data),
        );
      }
    });

    FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) async {
      print("onMessageOpenedApp: $message");

      if (message.data != null) {
        print(message.data);
      }
    });

    FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
  }

  Future onSelectNotification(String payload) async {
    Map data = json.decode(payload);

    if (data['type'] == 'message') {
      // NEED TO ACCESS CONTEXT HERE
      // Navigator.push(
      //   navigatorKey.currentState.context,
      //   CupertinoPageRoute(
      //     builder: (navigatorKey.currentState.context) => MessagesScreen(
      //       conversationId: data['conversation_id'],
      //       userId: data['user_id'],
      //       name: data['name'],
      //       avatar: data['avatar'],
      //       projectName: data['project_name'],
      //       projectId: data['project_id'],
      //       plus: data['plus'],
      //     ),
      //   ),
      // );
    }
  }

  Future<void> _firebaseMessagingBackgroundHandler(
      RemoteMessage message) async {
    print("onBackgroundMessage: $message");
  }

  enableIOSNotifications() async {
    await FirebaseMessaging.instance
        .setForegroundNotificationPresentationOptions(
      alert: true,
      badge: true,
      sound: true,
    );
  }

  androidNotificationChannel() => const AndroidNotificationChannel(
        'high_importance_channel', // id
        'High Importance Notifications', // title
        importance: Importance.max,
      );
}

正如您在 onSelectNotification() 函数中看到的，我正在尝试导航，但不知道如何进行。

我对 dart/flutter 很陌生，所以任何指导将不胜感激。

Answer 1

您可以为导航设置全局键：

   final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();

将其传递给 MaterialApp：

 new MaterialApp(
          title: 'MyApp',
          onGenerateRoute: generateRoute,
          navigatorKey: navigatorKey,
        );

推送路线：

    navigatorKey.currentState.pushNamed('/someRoute');

Answer 2

我需要访问 BuildContext

是的，您需要 context 进行导航。在 flutter 中，最佳实践是在小部件中包含导航代码。并且您的上下文

来自 Andrea Bizzotto 的 推文主题

规则：导航代码属于小部件

如果您尝试将导航代码放入业务逻辑中，您将遇到困难，因为您需要一个 BuildContext 来执行此操作。

解决方案：

• 发出一个新的小部件状态，
• 监听小部件中的状态并在那里执行导航

Answer 3

创建一个流

StreamController<Map<String, dynamic>> streamController = StreamController<Map<String, dynamic>>();

，然后在此处使用它

Future onSelectNotification(String payload) async {
    Map data = json.decode(payload);
      _streamController.add(data)
  }
}

，然后您可以在主页上的 MaterialApp 小部件下收听该流

  @override
  void initState() {
    streamController.stream.listen((event) {
      if (data['type'] == 'message') {
        Navigator.of(context).push(
          CupertinoPageRoute(
            builder: (context) => MessagesScreen(
              conversationId: data['conversation_id'],
              userId: data['user_id'],
              name: data['name'],
              avatar: data['avatar'],
              projectName: data['project_name'],
              projectId: data['project_id'],
              plus: data['plus'],
            ),
          ),
        );
      }
    });
    super.initState();
  }

Answer 4

自动路线解决方案

对于使用 auto_route 包进行导航的任何人，以下是在没有上下文的情况下进行导航的步骤。

1 - 将您的 AppRouter 添加到 get_it

要在应用程序中的任何位置访问您的 AppRouter，您可以使用服务定位器注册它，例如 get_it :

getIt.registerSingleton<AppRouter>(AppRouter());

2 - 在 GetIt 中访问 AppRouter

getIt.get<AppRouter>().push(HomeViewRoute())