App 在前台时获取本地通知 Swift 4 iOS 11

Question

我想在我的应用程序处于前台时收到本地通知，当我尝试使用以下代码时它从未触发通知，但当我在后台进入应用程序时它确实触发了。

这是我尝试过的：

//Schedule a Local Notification
func ScheduleNotification(timeInterval: Double, repeats: Bool, notificationBody:String, title:String){

    let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval: timeInterval, repeats: repeats)

    let center = UNUserNotificationCenter.current()

    let identifier = "UYLLocalNotification"
    let content = UNMutableNotificationContent()
    content.title = title
    content.body = notificationBody
    content.sound = UNNotificationSound.default()
    let request = UNNotificationRequest(identifier: identifier, content: content, trigger: trigger)
    center.add(request, withCompletionHandler: { (error) in
        if let error = error {
            //Something went wrong
            print(error.localizedDescription)
        }
    })
}

override func viewDidLoad() {
    super.viewDidLoad()

    if Currentcount < data.count {
        self.ScheduleNotification(timeInterval: 5.0, repeats: false, notificationBody: "You have \(data.count - Currentcount) notification", title: "Alert!")
    }
}

如有任何帮助，我们将不胜感激谢谢

Answer 1

当您的应用程序处于前台时，通知也可能会触发。

默认情况下，当通知到达且目标应用程序位于前台时，iOS 不会显示任何 UI。显示通知内容是应用程序的工作。使用 UNUserNotificationCenterDelegate 您可以非常轻松地将通知显示为警报。有关详细信息，请参阅。

Answer 2

这里我一步步给大家展示UNUserNotificationCenterDelegate是如何工作的

在 AppDelegate 中：import UserNotifications
class AppDelegate: UIResponder,UNUserNotificationCenterDelegate{}

在 didFinishLaunchingWithOptions

中将委托方法分配给 self

func application(_application:UIApplication,
didFinishLaunchingWithOptionslaunchoptions:[UIApplicationLaunchOptionsKey: Any]?) -> Bool {

       UIApplication.shared.applicationIconBadgeNumber = 0
            let center = UNUserNotificationCenter.current()
            center.delegate = self        
            center.requestAuthorization(options:[.badge, .alert, .sound]) { (granted, error) in

                if granted {
                    DispatchQueue.main.async { // Correct
                        UIApplication.shared.registerForRemoteNotifications()
                    }

                }

            }

    }

您希望在本地通知中显示的内容

     func assignValueToNotification
        {
            let content = UNMutableNotificationContent()
            content.body = "Asssign body"
            content.userInfo = ["identifier": "info"]
            content.sound = UNNotificationSound.default()
            content.badge = UIApplication.shared.applicationIconBadgeNumber + 1 as NSNumber;
            content.categoryIdentifier = "write category identifier"
            // Deliver the notification in five seconds.
            let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval: 0.5, repeats: false)
            let request = UNNotificationRequest.init(identifier: region.identifier as String, content: content, trigger: trigger)
           // Schedule the notification.
           let center = UNUserNotificationCenter.current()
           center.add(request)
    }

写下您的委托方法，当您单击本地通知时将调用该方法。

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

Answer 3

您只需将 UNUserNotificationCenterDelegate 的 willPresent 委托函数添加到您的 AppDelegate。

只需将 .sound, .banner UNNotificationPresentationOptions 放入完成处理程序，您的本地通知就会在您的应用程序位于前台时显示。

extension AppDelegate: UNUserNotificationCenterDelegate {
    
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler([.sound, .banner])
    }
}

还有一步：你当然需要在 didFinishLaunchingWithOptions.

中设置 UNUserNotificationCenter 委托

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {  
    UNUserNotificationCenter.current().delegate = self
}

备注

对于 SwiftUI Cycles，您可以像这样访问 AppDelegate：

App 在前台时获取本地通知 Swift 4 iOS 11

Get local notification when App is in foreground Swift 4 iOS 11

ios

swift

uilocalnotification

备注