问带有自定义声音的UNMutableNotificationContent

EN

import UIKit
import UserNotifications

class HomeViewController: UIViewController, UNUserNotificationCenterDelegate {

    @IBOutlet weak var btnNotification: UIButton!

    @IBAction func triggerNotification(_ sender: Any) {
        /* let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertController.Style.alert)
        alert.addAction(UIAlertAction(title: "Click", style: UIAlertAction.Style.default, handler: nil))
        self.present(alert, animated: true, completion: nil) */
        execNotification()

    }

    override func viewDidLoad() {
        super.viewDidLoad()
        UNUserNotificationCenter.current().delegate = self

    }

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

    private func execNotification() {
        let notificationContent = UNMutableNotificationContent()
        notificationContent.title = "UNUserNotification Sample"
        notificationContent.body = "Sample test msg"
        notificationContent.badge = 0
        notificationContent.sound = UNNotificationSound(named: UNNotificationSoundName(rawValue: "alert.caf"))
        notificationContent.categoryIdentifier = "GENERAL"

        let notificationTrigger = UNTimeIntervalNotificationTrigger(timeInterval: 0.2, repeats: false)
        let notificationRequest = UNNotificationRequest(identifier: "general", content: notificationContent, trigger: notificationTrigger)

        // Add Request to User Notification Center
        UNUserNotificationCenter.current().add(notificationRequest) { (error) in
            if let error = error {
                print("Unable to Add Notification Request (\(error), \(error.localizedDescription))")
            }
        }

    }

}