ios - Swift - UNUsernotification 检查 BadgeNumberIcon 中的更改

Question

我想在标签中显示角标(Badge)编号的值。

到目前为止，我已将所有内容都放在我的 viewWillAppear 中。因此每次加载 Controller 时都会分配变量。这是代码:

var deliveredNotif = Int()

 override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
deliveredNotif = UIApplication.shared.applicationIconBadgeNumber
myBadgeLabel.text = "\(deliveredNotif)"
}

我的问题是:如果 Controller 处于事件状态并且已调用 viewWillAppear，我如何更新 deliveredNotif？这意味着如果我在 Controller 中，是否有一种方法可以触发一个函数，它会在每次更改 applicationIconBadgeNumber 的值时更新 deliveredNotif 的值？

谢谢!

--------更新----我的解决方案我创建了一个常量变量:var iconBadgeNumber = NSNumber()

在我的 Appdelegate 中我有:

func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    completionHandler([.alert, .badge])
    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "applicationIconBadgeNumber"), object: nil)
    iconBadgeNumber = UIApplication.shared.applicationIconBadgeNumber + 1 as NSNumber
}

然后在我的 Controller 中:

override func viewDidLoad() {
    super.viewDidLoad()
 NotificationCenter.default.addObserver(self, selector: #selector(updateIconBadgeNumber), name: NSNotification.Name(rawValue: "applicationIconBadgeNumber"), object: nil)


}

@objc func updateIconBadgeNumber() {
    if iconBadgeNumber == 0 {
        print("zero")
    } else {
    print("there unread notification")
    }
}

Answer 1

您可以将您的 UIViewController 设置为关键路径“applicationIconBadgeNumber”的观察者:

首先注册远程通知。在 didFinishLaunchingWithOptions 函数中，添加:

    let center = UNUserNotificationCenter.current()
    center.requestAuthorization(options: [.alert, .badge, .sound]) { _, _ in
        DispatchQueue.main.async {
            application.registerForRemoteNotifications()
        }
    }

不要忘记在文件顶部添加:import UserNotifications

然后在你的viewDidLoad中添加:

UIApplication.shared.addObserver(self, forKeyPath: "applicationIconBadgeNumber", options: .new, context: nil)

然后，覆盖 observeValue 函数:

    override func observeValue(forKeyPath keyPath: String?,
                                        of object: Any?,
                                           change: [NSKeyValueChangeKey : Any]?,
                                          context: UnsafeMutableRawPointer?) {
        if keyPath == "applicationIconBadgeNumber" {
            deliveredNotif = UIApplication.shared.applicationIconBadgeNumber
            myBadgeLabel.text = "\(deliveredNotif)"
        }
    }