每日本地通知不起作用

我的问题是我正在尝试安排每天在特定时间发出的通知，这是我的代码

import SwiftUI

struct notifView: View {
    var body: some View {
        VStack {
            VStack {
                Button("Request Permission") {
                    let center = UNUserNotificationCenter.current()

                    center.requestAuthorization(options: [.alert, .badge, .sound]) { (granted, error) in
                        if granted {
                            print("Access Granted!")
                        } else {
                            print("Access Not Granted")
                        }
                    }
                }
                .frame(width: 200, height: 60, alignment: .center)
                .foregroundColor(.black)
                .background(Color.blue)
                .cornerRadius(10.0)
                .padding()
                Button("Add Notifications For Morning") {
                    func scheduleNotification() {
                        let center = UNUserNotificationCenter.current()

                        let content = UNMutableNotificationContent()
                        content.title = "Morning Time"
                        content.body = "Wake Up And Be Productive!"
                        content.categoryIdentifier = "reminder"
                        content.sound = UNNotificationSound.default

                        var dateComponents = DateComponents()
                        dateComponents.hour = 6
                        dateComponents.minute = 30
                        let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)

                        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
                        center.add(request)
                    }
                }
                .padding()
                Button("Add Notifications For Middle Of The Day") {
                    func scheduleNotification() {
                        let center = UNUserNotificationCenter.current()

                        let content = UNMutableNotificationContent()
                        content.title = "Middle Of The Day"
                        content.body = "Did you have your daily run?"
                        content.categoryIdentifier = "reminder"
                        content.sound = UNNotificationSound.default

                        var dateComponents = DateComponents()
                        dateComponents.hour = 12
                        dateComponents.minute = 30
                        let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)

                        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
                        center.add(request)
                    }
                }
                .padding()
                Button("Add Notifications For Night") {
                    func scheduleNotification() {
                        let center = UNUserNotificationCenter.current()

                        let content = UNMutableNotificationContent()
                        content.title = "Night Time"
                        content.body = "Time to sleep"
                        content.categoryIdentifier = "reminder"
                        content.sound = UNNotificationSound.default

                        var dateComponents = DateComponents()
                        dateComponents.hour = 20
                        dateComponents.minute = 51
                        let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)

                        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
                        center.add(request)
                    }
                }
                .foregroundColor(.blue)
                .padding()
            }
        }
    }
}

struct notifView_Previews: PreviewProvider {
    static var previews: some View {
        notifView()
    }
}

看一下代码中的注释

import SwiftUI
//struct and class should start with an uppercase
struct NotificationView: View {
    //Central location for Notification code including the delegate
    // A call to the notificationManager just like the line of code below has to be included in
    // application(_:willFinishLaunchingWithOptions:) or
    // application(_:didFinishLaunchingWithOptions:)
    //https://developer.apple.com/documentation/usernotifications/unusernotificationcenterdelegate
    //https://www.hackingwithswift.com/quick-start/swiftui/how-to-add-an-appdelegate-to-a-swiftui-app
    let notificationManager: NotificationManager = NotificationManager.shared
    var body: some View {
        VStack {
            VStack {
                Button("Request Permission") {
                    //Call a func here don't define it
                    notificationManager.requestAuthorization()
                }
                .frame(width: 200, height: 60, alignment: .center)
                .foregroundColor(.black)
                .background(Color.blue)
                .cornerRadius(10.0)
                .padding()
                Button("Add Notifications For Morning") {
                    //Unique date components
                    var dateComponents = DateComponents()
                    dateComponents.hour = 6
                    dateComponents.minute = 30
                    //Reusable method
                    self.notificationManager.scheduleTriggerNotification(title: "Morning Time", body: "Wake Up And Be Productive!", categoryIdentifier: "reminder", dateComponents: dateComponents, repeats: true)
                }
                .padding()
                Button("Add Notifications For Middle Of The Day") {
                    var dateComponents = DateComponents()
                    dateComponents.hour = 12
                    dateComponents.minute = 30
                    //Reusable method
                    self.notificationManager.scheduleTriggerNotification(title: "Middle Of The Day", body: "Did you have your daily run?", categoryIdentifier: "reminder", dateComponents: dateComponents, repeats: true)
                    
                }
                .padding()
                Button("Add Notifications For Night") {
                    var dateComponents = DateComponents()
                    dateComponents.hour = 20
                    dateComponents.minute = 51
                    //Reusable method
                    self.notificationManager.scheduleTriggerNotification(title: "Night Time", body: "Time to sleep", categoryIdentifier: "reminder", dateComponents: dateComponents, repeats: true)
                    
                }
                .foregroundColor(.blue)
                .padding()
                
                Button("Print Notifications") {
                    //Reusable method
                    self.notificationManager.printNotifications()
                }
                .foregroundColor(.blue)
                .padding()
                Button("Delete Notifications") {
                    //Reusable method
                    self.notificationManager.deleteNotifications()
                }
                .foregroundColor(.blue)
                .padding()
            }
        }
    }
}
//You need a central location for the notification code because
// it is needed in more than 1 spot. At launch in the AppDelegate
// and wherever you schedule your notifications
class NotificationManager: NSObject, UNUserNotificationCenterDelegate{
    //Singleton is requierd because of delegate
    static let shared: NotificationManager = NotificationManager()
    let notificationCenter = UNUserNotificationCenter.current()
    
    private override init(){
        super.init()
        //This assigns the delegate
        notificationCenter.delegate = self
    }
    
    func requestAuthorization() {
        print(#function)
        notificationCenter.requestAuthorization(options: [.alert, .badge, .sound]) { (granted, error) in
            if granted {
                print("Access Granted!")
            } else {
                print("Access Not Granted")
            }
        }
    }
    
    func deleteNotifications(){
        print(#function)
        notificationCenter.removeAllPendingNotificationRequests()
    }
    ///This is just a reusable form of all the copy and paste you did in your buttons. If you have to copy and paste make it reusable.
    func scheduleTriggerNotification(title: String, body: String, categoryIdentifier: String, dateComponents : DateComponents, repeats: Bool) {
        print(#function)
        let content = UNMutableNotificationContent()
        content.title = title
        content.body = body
        content.categoryIdentifier = categoryIdentifier
        content.sound = UNNotificationSound.default
        
        let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: repeats)
        
        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
        notificationCenter.add(request)
    }
    ///Prints to console schduled notifications
    func printNotifications(){
        print(#function)
        notificationCenter.getPendingNotificationRequests { request in
            for req in request{
                if req.trigger is UNCalendarNotificationTrigger{
                    print((req.trigger as! UNCalendarNotificationTrigger).nextTriggerDate()?.description ?? "invalid next trigger date")
                }
            }
        }
    }
    //MARK: UNUserNotificationCenterDelegate
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        
        completionHandler(.banner)
    }
}
struct NotificationView_Previews: PreviewProvider {
    static var previews: some View {
        NotificationView()
    }
}