ios - 为什么我无法使用 swift 3 在 iOS 上获取本地通知？

Question

在 Xcode 8.3 和 swift 3.1 上运行

下面是我在 AppDelegate.swift 中的代码

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

    let center = UNUserNotificationCenter.current()

    center.requestAuthorization(options: [.alert, .sound, .badge], completionHandler: { granted, error in
        if granted {
            print("User accept notification。")
        }
        else {
            print("User don't like receive any notification!")
        }
    })

    let content = UNMutableNotificationContent()
    content.title = "Will it rain?"
    content.body = "It never rains in (Southern) California!"
    content.sound = UNNotificationSound.default()

    let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)
    let request = UNNotificationRequest(identifier: "local_notification", content: content, trigger: trigger)

    center.add(request)

    return true
}

我在 iPhone 上构建并运行它，并会显示一条消息，询问我是否愿意接收任何通知，然后单击“接受”。

然后，什么也没有发生。

我希望它会显示来自本地的通知，其中包含一些文本“会下雨吗”，就像我的代码中一样。

Answer 1

您必须让您的 AppDelegate 采用 UNUserNotificationCenterDelegate

在 applicationDidFinishLaunching 方法中，添加此 center.delegate = self

然后实现这段代码:

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

来自苹果文档:

To respond to the delivery of notifications, you must implement a delegate for the shared UNUserNotificationCenter object. Your delegate object must conform to the UNUserNotificationCenterDelegate protocol, which the notification center uses to deliver notification information to your app. A delegate is required if your notifications contain custom actions.

引用: https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/SchedulingandHandlingLocalNotifications.html

https://developer.apple.com/reference/usernotifications/unusernotificationcenterdelegate