Flutter Firebase 前台推送通知未显示，但后台正在运行

Question

自从我尝试解决这个问题以来已经好几天了。我已经实现了用于推送通知的 firebase 消息传递，因此，当应用程序位于后台时，我能够收到通知，但当应用程序位于前台时，我无法收到通知。我尝试了所有可能的解决方案或在 stackoverflow/github 上尝试，但到目前为止没有任何效果。以下是我尝试过的来源：

堆栈溢出解决方案 1

堆栈溢出解决方案2

当前代码 =>

NotificationService.dart:

class NotificationService {
  static final FlutterLocalNotificationsPlugin
      _flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();

  static Future initialize() async {
    final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
        FlutterLocalNotificationsPlugin();

    AndroidInitializationSettings androidInitializationSettings =
        AndroidInitializationSettings('@mipmap/ic_launcher');

    InitializationSettings initializationSettings =
        InitializationSettings(android: androidInitializationSettings);

    await flutterLocalNotificationsPlugin.initialize(
      initializationSettings,
      // onSelectNotification: doSomething(),
    );
  }

  static Future showNotification(RemoteMessage message) async {
    AndroidNotificationDetails androidDetails = AndroidNotificationDetails(
      "default_notification_channel_id",
      "channel",
      enableLights: true,
      enableVibration: true,
      priority: Priority.high,
      importance: Importance.max,
      largeIcon: DrawableResourceAndroidBitmap("ic_launcher"),
      styleInformation: MediaStyleInformation(
        htmlFormatContent: true,
        htmlFormatTitle: true,
      ),
      playSound: true,
    );

    await _flutterLocalNotificationsPlugin.show(
        message.data.hashCode,
        message.data['title'],
        message.data['body'],
        NotificationDetails(
          android: androidDetails,
        ));
  }
}

main.dart:

Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  await Firebase.initializeApp();
  print('Handling a background message ${message.messageId}');
  print('Notification Message: ${message.data}');
  NotificationService.showNotification(message);
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
  runApp(
    MyApp(),
  );
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {

  @override
  void initState() {
    super.initState();
    NotificationService.initialize();
    FirebaseMessaging.onMessage.listen((RemoteMessage message) {
      NotificationService.showNotification(message);
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(...)

还要补充一点，当应用程序处于后台时（我可以收到通知的情况），我得到前 2 个print语句的输出，即message.messageId和message.data：

I/flutter ( 3363): Handling a background message 0:1637822186109880%5dd28a92f9fd7ecd
I/flutter ( 3363): Notification Message: {body: Price is at Bull! Buy Now!, title: Hello Traders!}

但是当应用程序位于前台时（我没有收到通知的情况），我得到以下输出：D/FLTFireMsgReceiver( 3363): broadcast received for message

如果有人能帮助我，那真的会有帮助，这几天一直在调试，找到解决方案。谢谢你！

AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.trading_app">

  <uses-permission android:name="android.permission.VIBRATE"/>
  <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
  <uses-permission android:name="android.permission.INTERNET"/>

   <application
        android:label="TradingApp"
        android:icon="@mipmap/ic_launcher">

        <meta-data
            android:name="com.google.firebase.messaging.default_notification_icon"
            android:resource="@mipmap/ic_launcher" />

        <meta-data         
            android:name="com.google.firebase.messaging.default_notification_channel_id"                 
            android:value="@string/default_notification_channel_id" />

        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver">
        <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED"></action>
        </intent-filter>
        </receiver>
        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationReceiver" />

        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">

            <meta-data
              android:name="io.flutter.embedding.android.NormalTheme"
              android:resource="@style/NormalTheme"
              />

            <meta-data
              android:name="io.flutter.embedding.android.SplashScreenDrawable"
              android:resource="@drawable/launch_background"
              />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>

        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
            <!-- <meta-data
            android:name="com.google.firebase.messaging.default_notification_channel_id"
            android:value="high_importance_channel" /> -->
    </application>
</manifest>

Answer 1

我不知道它是否适合您，但这是我的代码，用于在应用程序位于前台时显示通知。我将 messageHandler 放在 initState() 上。LocalNotification是一个自定义类，因此您可以创建相同的类，或者只是将其中的任何内容showNotification放入onMessage

  Future<void> messageHandler() async {
  await FirebaseMessaging.instance.setForegroundNotificationPresentationOptions(
    alert: true,
    badge: true,
    sound: true,
  );

  FirebaseMessaging.onMessage.listen((RemoteMessage event) {
    LocalNotification.showNotification(event);
  });

}

  static Future<void> showNotification(RemoteMessage payload) async {

    var android = AndroidInitializationSettings('logo_rs');
    var initiallizationSettingsIOS = IOSInitializationSettings();
    var initialSetting = new InitializationSettings(android: android, iOS: initiallizationSettingsIOS);
    final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
    flutterLocalNotificationsPlugin.initialize(initialSetting);



    const AndroidNotificationDetails androidDetails = AndroidNotificationDetails(
        'default_notification_channel_id',
        'Notification',
        'All Notification is Here',
        importance: Importance.max,
        priority: Priority.high,
        ticker: 'ticker',
        icon: "logo_rs",
        playSound: true,
        sound: RawResourceAndroidNotificationSound("notification")
    );
    const iOSDetails = IOSNotificationDetails();
    const NotificationDetails platformChannelSpecifics = NotificationDetails(android: androidDetails, iOS: iOSDetails);

    await flutterLocalNotificationsPlugin.show(0, payload.notification!.title, payload.notification!.body, platformChannelSpecifics);
  }

添加尝试将其放在您的 AndroidManifest 中

   <meta-data  android:name="com.google.firebase.messaging.default_notification_channel_id"
                android:value="@string/default_notification_channel_id" />

String.xml（res/values 内的新文件）

<?xml version='1.0' encoding='utf-8'?>
<resources>
    <string name="default_notification_channel_id" translatable="false">fcm_default_channel</string>
</resources>