未调用UNUserNotificationCenter didReceive

Question

当我发送推送通知，并且应用程序在前台时，将调用willPresent。永远不会调用didReceive。当应用程序在后台并收到推送通知时，将显示警报，但应用程序永远不会调用didReceive或willPresent。

在“项目”>“功能”中，我选中了背景模式Location updates和Remote notifications。位置更新适用于不相关的代码。

我还启用了推送通知。这工作得很好，因为它们正在被接收。

我已经在我的AppDelegate中实现了UNUserNotificationCenter通知的东西，如下所示：

import UserNotifications
...

class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {
...

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        ...
        registerForPushNotifications(application: application)
        ...
    }

    // MARK: - Push Notifications

    func registerForPushNotifications(application: UIApplication) {
        let notificationCenter = UNUserNotificationCenter.current()
        notificationCenter.delegate = self
        notificationCenter.requestAuthorization(options: [.badge, .sound, .alert], completionHandler: {(granted, error) in
            if (granted)
            {
                UIApplication.shared.registerForRemoteNotifications()
            }
            else{
                //Do stuff if unsuccessful...
                print("Unsuccessful in registering for push notifications")
            }
        })
    }

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        //convert the deviceToken to a string
        let deviceTokenString = deviceToken.map { String(format: "%02.2hhx", arguments: [$0]) }.joined()

        let ud = UserDefaults.standard
        ud.set(deviceTokenString, forKey: "deviceToken")
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        //Handle the notification
        print("User Info = ",notification.request.content.userInfo)
        completionHandler([.alert, .badge, .sound])
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
        //handle the notification
        print("Push notification: ",response.notification.request.content.userInfo)

        ... code to import the notification data into Core Data.

        completionHandler()
    }

...
}

你知道为什么didReceive没有被调用吗？

这是收到的推送通知：

[AnyHashable("aps"): {
    alert = "[name] has added you as a friend.";
    category = "NEWS_CATEGORY";
    "related_user_id" = 55;
    sound = default;
    type = "friend_request";
}]

iOS 10.1，Swift 3。

Answer 1

我发现我需要在获得权限后设置委托。

否则，当你第一次运行应用程序时，你在获得权限之前注册了委托，didReceive函数不会被触发-这只发生在你第一次运行应用程序时，在kill并重新启动之后，它被调用得很好。

如下所示：

 UNUserNotificationCenter.current().requestAuthorization(options: authOptions, completionHandler: { (granted, error) in
        if granted {
            // Register after we get the permissions.
            UNUserNotificationCenter.current().delegate = self
        }
    })

Answer 2

didReceive不会在您收到通知时执行，而是在用户对收到的通知执行操作时执行

来自https://developer.apple.com/documentation/usernotifications/unusernotificationcenterdelegate上的苹果文档

调用以让您的应用程序知道用户为给定通知选择了哪个操作。

这意味着当用户对接收到的通知执行操作(推送通知、向下滑动等)时，将调用此方法

Answer 3

如果您点击通知横幅，将调用willPresent方法。

如果您希望在后台处理推送通知，而不必点击横幅，则应将{"content-available":1}附加到您的通知有效负载。这种类型的推送通知称为静默推送。这将不会像普通推送那样创建通知横幅/警报，您将不得不自己创建横幅。

当您收到带有content-available的推送通知时，会在应用后台调用didReceive委托方法。

注意:您还必须在plist文件的UIBackgroundModes密钥中添加‘远程通知’。