使用未声明的类型 'UNUserNotificationCenter'

Question

我想在应用程序处于前台时显示推送通知的横幅。我实现了这个方法来显示通知：

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

但是收到此错误使用未声明的类型'UNUserNotificationCenter'

Answer 1

您所要做的就是导入 UserNotifications 框架：

import UserNotifications

此外，请确保您符合 UNUserNotificationCenterDelegate。作为一种好的做法，我建议通过将其实现为 extension:

_{如果您不熟悉 Delegation，您可能需要查看。}

import UIKit
// add this:
import UserNotifications

class ViewController: UIViewController {
    .
    .
    .

    // somewhere in your code:
    UNUserNotificationCenter.current().delegate = delegateObject
}

// add this:
// MARK:- UserNotifications
extension ViewController: UNUserNotificationCenterDelegate {
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void)
    {
        completionHandler([.alert, .badge, .sound])
    }
}

使用未声明的类型 'UNUserNotificationCenter'

Use of undeclared type 'UNUserNotificationCenter'

ios

swift

unusernotificationcenter