Flutter集成自定义iOS Notification Service Extension失效求助

我在Flutter应用中添加了自定义iOS Notification Service Extension，用于预处理Firebase Cloud Messaging（FCM）推送的通知，但扩展完全不生效，测试通知却可正常显示。由于使用Windows系统，我通过MacInACloud的Xcode添加了该扩展，生成了与Runner、Flutter同级的新文件夹。

Notification Service扩展代码 #

import UserNotifications

class NotificationService: UNNotificationServiceExtension {

    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)
        
        if let bestAttemptContent = bestAttemptContent {
            // Modify the notification content here...
            bestAttemptContent.title = "modified !"
            
            contentHandler(bestAttemptContent)
        }
    }
    
    override func serviceExtensionTimeWillExpire() {
        // Called just before the extension will be terminated by the system.
        // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
        if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
            contentHandler(bestAttemptContent)
        }
    }

}

AppDelegate代码 #

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
     if #available(iOS 10.0, *) {
      UNUserNotificationCenter.current().delegate = self as? UNUserNotificationCenterDelegate
    }
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

FCM推送Payload #

const payload = {
      "token":"evGbKFWA10fFoD2rsTUVOX:APA91bHfOZDkkcim2SjHB1-H5ldZu37OsE3G91s4xRYkbp4vK3PUodvNkzLurAONzxI5NUjf5tzmokfGUBu9avT4y_Uz3L6DpKJ_pMR43knNVctFAobtQupcdy_P_H58q1EtRU02TZ8D",
      "notification":{ 
        "title":"Secret Message !",
        "body" : "Nothing",
      },
      
      "content-available":0,
      "apns":{ 
        "headers":{ 
          "apns-priority":10,
        },
        "payload": {
          "aps" : {
            "category" : "SECRET",
            "mutable-content" : 1,
            "alert" : {
              "title" : "Secret Message!",
                "body"  : "(Encrypted)"
            },
          },
          "ENCRYPTED_DATA" : "Salted__·öîQÊ$UDì_¶Ù∞èΩ^¬%gq∞NÿÒQùw"
        },
      }
  };

失效原因排查及解决方案 #

• FCM Payload冲突：当同时指定顶层notification字段和apns.payload时，FCM会优先使用notification字段的内容，这类推送会直接展示，不会触发Notification Service Extension。需要删除顶层的notification字段，仅保留apns.payload中的配置，确保推送触发扩展。

• AppDelegate委托配置错误：FlutterAppDelegate本身已经实现了UNUserNotificationCenterDelegate协议，无需再手动赋值UNUserNotificationCenter.current().delegate = self as? UNUserNotificationCenterDelegate，这行代码会导致委托设置异常，直接删除即可。

• Extension Bundle ID配置错误：Apple要求Notification Service Extension的Bundle ID必须是主App Bundle ID的子ID形式（例如主App为com.example.myapp，Extension需为com.example.myapp.notification-service），检查Xcode中Extension的Bundle ID是否符合要求。

• Extension部署目标不一致：确保Extension的Deployment Target版本与主App保持一致，不能低于主App的版本，否则扩展无法正常触发。

• Extension Info.plist配置缺失：检查Extension的Info.plist，确认NSExtension字典配置正确：

  • NSExtensionPointIdentifier必须为com.apple.usernotifications.service
  • NSExtensionPrincipalClass需指向你的NotificationService类（格式为$(PRODUCT_MODULE_NAME).NotificationService）

• 依赖集成问题：在MacInACloud中打开项目时，需确保Extension的Target已集成必要依赖（如Firebase Messaging）。在Podfile中添加Extension的Target配置：

  target 'NotificationServiceExtension' do
    use_frameworks!
    pod 'Firebase/Messaging'
  end
  

  执行pod install后重新编译项目。

• 测试环境限制：Notification Service Extension仅在真实iOS设备上生效，模拟器不支持该功能；同时需确保App处于后台或终止状态，前台推送由AppDelegate处理，不会触发扩展。

内容的提问来源于stack exchange，提问作者aloys-c