iOS-应用程序处于后台时异步

我正在尝试运行一个简单的iOS应用程序，在指定时间后将通知推送到用户屏幕

到目前为止，这是我所拥有的（从另一个线程借用）：

我唯一的问题是aSync After不会在应用程序处于后台时运行

例如，如果用户进入锁屏或其他应用程序，则不会触发通知

谁能给我一个建议，让我如何做到这一点

谢谢！：）

方法：

• 按时间间隔使用

  UNNotificationRequest

• 以下提到的解决方案将在以下情况下工作：
  • 前景
  • 背景
  • 应用程序已关闭

步骤：

设置代理（在前台发出警报）

向用户请求授权以获得警报

创建通知

将其添加到通知中心

AppDelegate：

AppDelegate

必须符合

UNUserNotificationCenterDelegate

将通知中心的委托设置为

AppDelegate

import UserNotifications

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

        UNUserNotificationCenter.current().delegate = self

        return true
    }

    //MARK: UNUserNotificationCenterDelegate

    //This is required to be alerted when app is in foreground
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification,
                                withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        print("will present")
        completionHandler([.alert, .badge, .sound])
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                didReceive response: UNNotificationResponse,
                                withCompletionHandler completionHandler: @escaping () -> Void) {
        print("did receive")
    }
}

设置通知：

---

您不能在后台执行任意的、基于计时器的代码。您需要通过在

触发器中指定所需的发送时间来安排通知的发送，但这并不能回答问题。具体来说，它没有显示如何在后台延迟执行任务（不是通知）
import UserNotifications

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

        UNUserNotificationCenter.current().delegate = self

        return true
    }

    //MARK: UNUserNotificationCenterDelegate

    //This is required to be alerted when app is in foreground
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification,
                                withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        print("will present")
        completionHandler([.alert, .badge, .sound])
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                didReceive response: UNNotificationResponse,
                                withCompletionHandler completionHandler: @escaping () -> Void) {
        print("did receive")
    }
}

import UserNotifications

private func setupNotification() {

    requestAuthorization { [weak self] isGranted, error in

        if let error = error {

            print("Request Authorization Error: \(error)")
            return
        }

        guard isGranted else {
            print("Authorization Denied")
            return
        }

        self?.addNotification()
    }
}

private func requestAuthorization(completionBlock: @escaping (Bool, Error?) -> ()) {

    let center = UNUserNotificationCenter.current()

    center.requestAuthorization(options: [.alert, .badge, .sound]) { isGranted, error in

        completionBlock(isGranted, error)
    }
}


private func addNotification() {

    let content = UNMutableNotificationContent()

    content.title = "Testing Notification"
    content.body = "This is a test for notifications"
    content.sound = .default()

    let timeInterval = TimeInterval(5)
    let trigger = UNTimeIntervalNotificationTrigger(timeInterval: timeInterval, repeats: false)

    let request = UNNotificationRequest(identifier: "Something",
                                        content: content,
                                        trigger: trigger)


    let center = UNUserNotificationCenter.current()

    center.add(request) { error in

        if let error = error {
            print("Error adding notification request: \(error)")
        }
        else {
            print("Successfully added notification request")
        }
    }
}