每 n 天安排一次本地通知（时区安全）

Question

我相信这个问题已经被问过好几次了，但没有明确的答案。

有两种方法可以安排临时通知：UNCalendarNotification和 UNTimeIntervalNotificationTrigger。

安排一个特定时间和一周中的某一天的通知很简单，与一个月中的特定一天相同，但安排一个特定的时间，每 n 天就不那么简单了。

例如，每 5 天 11:00。

UNTimeIntervalNotificationTrigger看起来似乎是合适的课程，但在夏令时或时区变化发生时会出现问题。例如，夏令时结束，现在您的通知时间为 10:00，而不是 11:00。

day类上的属性和DateComponents类UNCalendarNotification可能包含解决方案，因为它在文档中说“一天或天数”。我将其解释为“一个月中的特定一天（一天）或n天数（天数）”。

进一步深入研究day属性文档，它显示“此值在使用它的日历的上下文中进行解释”。

如何将该day属性与日历上下文一起使用来计算天数而不是每月的特定天数？

hour此外，和minute属性的文档DateComponents还分别为“一小时或数小时”和“一分钟或数分钟”。那么，即使您要设置day为“天数”，如何正确设置hour和呢？minute

很明显，此功能在 iOS 中是可行的 - 提醒应用程序就是证明。

Answer 1

您可以预先设置它们，使用UNCalendarNotificationTrigger多次n并使用针对当前时区调整后的日历

import SwiftUI

class NotificationManager: NSObject, UNUserNotificationCenterDelegate{
    static let shared: NotificationManager = NotificationManager()
    let notificationCenter = UNUserNotificationCenter.current()
    
    private override init(){
        super.init()
        requestNotification()
        notificationCenter.delegate = self
        getnotifications()
    }
    
    func requestNotification() {
        print(#function)
        notificationCenter.requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
            
            if let error = error {
                // Handle the error here.
                print(error)
            }
            
            // Enable or disable features based on the authorization.
        }
    }
    /// Uses [.day, .hour, .minute, .second] in current timeZone
    func scheduleCalendarNotification(title: String, body: String, date: Date, repeats: Bool = false, identifier: String) {
        print(#function)
        
        let content = UNMutableNotificationContent()
        content.title = title
        content.body = body
        
        let calendar = NSCalendar.current

        let components = calendar.dateComponents([.day, .hour, .minute, .second], from: date)
        
        let trigger = UNCalendarNotificationTrigger(dateMatching: components, repeats: repeats)
        
        let request = UNNotificationRequest(identifier: identifier, content: content, trigger: trigger)
        notificationCenter.add(request) { (error) in
            if error != nil {
                print(error!)
            }
        }
    }
    ///Sets up multiple calendar notification based on a date
    func recurringNotification(title: String, body: String, date: Date, identifier: String, everyXDays: Int, count: Int){
        print(#function)
        for n in 0..<count{
            print(n)
            let newDate = date.addingTimeInterval(TimeInterval(60*60*24*everyXDays*n))
            //Idenfier must be unique so I added the n
            scheduleCalendarNotification(title: title, body: body, date: newDate, identifier: identifier + n.description)
            print(newDate)
        }
    }
    ///Prints to console schduled notifications
    func getnotifications(){
        notificationCenter.getPendingNotificationRequests { request in
            for req in request{
                if req.trigger is UNCalendarNotificationTrigger{
                    print((req.trigger as! UNCalendarNotificationTrigger).nextTriggerDate()?.description ?? "invalid next trigger date")
                }
            }
        }
    }
    
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        
        completionHandler(.banner)
    }
}
class ZuluNotTriggerViewModel:NSObject, ObservableObject, UNUserNotificationCenterDelegate{
    @Published var currentTime: Date = Date()
    let notificationMgr = NotificationManager.shared
    
    
    ///Sets up multiple calendar notification based on a date
    func recurringNotification(title: String, body: String, date: Date, identifier: String, everyXDays: Int, count: Int){
        print(#function)
        notificationMgr.recurringNotification(title: title, body: body, date: date, identifier: identifier, everyXDays: everyXDays, count: count)
        
        //just for show now so you can see the current date in ui
        self.currentTime = Date()
    }
    ///Prints to console schduled notifications
    func getnotifications(){
        notificationMgr.getnotifications()
    }
    
}
struct ZuluNotTriggerView: View {
    @StateObject var vm: ZuluNotTriggerViewModel = ZuluNotTriggerViewModel()
    var body: some View {
        VStack{
            Button(vm.currentTime.description, action: {
                vm.currentTime = Date()
            })
            Button("schedule-notification", action: {
                let twoMinOffset = 120
                //first one will be in 120 seconds
                //gives time to change settings in simulator
                //initial day, hour, minute, second
                let initialDate = Date().addingTimeInterval(TimeInterval(twoMinOffset))
                //relevant components will be day, hour minutes, seconds
                vm.recurringNotification(title: "test", body: "repeat body", date: initialDate, identifier: "test", everyXDays: 2, count: 10)
            })
            
            Button("see notification", action: {
                vm.getnotifications()
            })
        }
    }
}

struct ZuluNotTriggerView_Previews: PreviewProvider {
    static var previews: some View {
        ZuluNotTriggerView()
    }
}