Flutter推送通知：如何禁用FCM自动通知或捕获后台数据消息？

需求1：阻止FCM自动创建通知，统一用flutter_local_notifications展示 #

Android 端配置 #

1. 自定义FirebaseMessagingService拦截通知，避免系统自动展示：
   在android/app/src/main/kotlin/[你的包名]/下创建CustomMessagingService.kt：

   import com.google.firebase.messaging.FirebaseMessagingService
   import com.google.firebase.messaging.RemoteMessage
   import io.flutter.plugins.firebase.messaging.FlutterFirebaseMessagingService
   
   class CustomMessagingService : FirebaseMessagingService() {
       override fun onMessageReceived(remoteMessage: RemoteMessage) {
           // 将消息转发给Flutter端处理
           FlutterFirebaseMessagingService.handleMessage(this, remoteMessage)
           // 不调用父类方法，阻止系统自动生成通知
       }
   }
   

2. 修改AndroidManifest.xml，替换默认服务：
   在application标签内添加：

   <service
       android:name=".CustomMessagingService"
       android:exported="false">
       <intent-filter>
           <action android:name="com.google.firebase.MESSAGING_EVENT" />
       </intent-filter>
   </service>
   

   移除原有默认的FirebaseMessagingService注册项。

iOS 端配置 #

修改AppDelegate.swift，设置通知代理拦截系统展示：

import UIKit
import Flutter
import Firebase
import UserNotifications

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate, UNUserNotificationCenterDelegate {
    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        FirebaseApp.configure()
        
        UNUserNotificationCenter.current().delegate = self
        let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
        UNUserNotificationCenter.current().requestAuthorization(
            options: authOptions,
            completionHandler: { _, _ in }
        )
        application.registerForRemoteNotifications()
        
        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
    
    // 拦截通知展示
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler([]) // 告诉系统不自动展示
        if let message = notification.request.content.userInfo as? [String: Any] {
            FirebaseMessaging.instance.app.send(message) // 转发给Flutter
        }
    }
    
    // 处理通知点击
    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
        if let message = response.notification.request.content.userInfo as? [String: Any] {
            FirebaseMessaging.instance.app.send(message)
        }
        completionHandler()
    }
}

Flutter 端统一处理 #

监听所有消息回调，用flutter_local_notifications展示：

import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';

final FlutterLocalNotificationsPlugin _notificationsPlugin = FlutterLocalNotificationsPlugin();
final FirebaseMessaging _firebaseMessaging = FirebaseMessaging.instance;

void setupNotifications() async {
  // 初始化本地通知插件
  const AndroidInitializationSettings androidSettings = AndroidInitializationSettings('@mipmap/ic_launcher');
  const DarwinInitializationSettings iosSettings = DarwinInitializationSettings();
  const InitializationSettings settings = InitializationSettings(android: androidSettings, iOS: iosSettings);
  await _notificationsPlugin.initialize(settings);

  // 前台消息监听
  FirebaseMessaging.onMessage.listen(showCustomNotification);
  // 后台/终止状态消息监听
  FirebaseMessaging.onBackgroundMessage(_handleBackgroundMessage);
}

void showCustomNotification(RemoteMessage message) async {
  String title = message.notification?.title ?? '新通知';
  String body = message.notification?.body ?? '您有一条新消息';
  String? customData = message.data['custom_key'];

  const AndroidNotificationDetails androidDetails = AndroidNotificationDetails(
    'custom_notification_channel',
    '自定义通知',
    importance: Importance.high,
    priority: Priority.high,
  );
  const DarwinNotificationDetails iosDetails = DarwinNotificationDetails();
  const NotificationDetails details = NotificationDetails(android: androidDetails, iOS: iosDetails);

  await _notificationsPlugin.show(
    DateTime.now().millisecondsSinceEpoch,
    title,
    body,
    details,
    payload: customData,
  );
}

// 后台消息处理（必须为顶级函数）
Future<void> _handleBackgroundMessage(RemoteMessage message) async {
  // 重新初始化本地通知插件
  const AndroidInitializationSettings androidSettings = AndroidInitializationSettings('@mipmap/ic_launcher');
  const DarwinInitializationSettings iosSettings = DarwinInitializationSettings();
  const InitializationSettings settings = InitializationSettings(android: androidSettings, iOS: iosSettings);
  final FlutterLocalNotificationsPlugin notificationsPlugin = FlutterLocalNotificationsPlugin();
  await notificationsPlugin.initialize(settings);

  String title = message.notification?.title ?? '新通知';
  String body = message.notification?.body ?? '您有一条新消息';

  const AndroidNotificationDetails androidDetails = AndroidNotificationDetails(
    'custom_notification_channel',
    '自定义通知',
    importance: Importance.high,
    priority: Priority.high,
  );
  const DarwinNotificationDetails iosDetails = DarwinNotificationDetails();
  const NotificationDetails details = NotificationDetails(android: androidDetails, iOS: iosDetails);

  await notificationsPlugin.show(
    DateTime.now().millisecondsSinceEpoch,
    title,
    body,
    details,
  );
}

需求2：后台/终止状态捕获仅数据消息并展示 #

前提配置 #

1. Android：完成需求1中的自定义FirebaseMessagingService配置。
2. iOS：在Xcode项目设置的Signing & Capabilities中，勾选Background Modes下的Remote notifications。

Flutter 端处理 #

复用需求1中的Flutter代码，核心是onBackgroundMessage回调——它会在应用终止或后台时触发数据消息的处理。

服务器数据消息格式 #

确保发送纯数据消息，示例结构：

{
  "message": {
    "token": "token_1",
    "data": {
      "title": "自定义标题",
      "body": "自定义内容",
      "custom_key": "自定义扩展数据"
    }
  }
}

Flutter端可从message.data中提取字段，用flutter_local_notifications展示。

内容的提问来源于stack exchange，提问作者Lalit Thakare