如何从特定的未来日期起每两周触发一次本地通知

Question

I am trying to trigger UNUserNotification fortnightly which will start from a specific future day. I have triggered successfully with UNTimeIntervalNotificationTrigger . But my problem is I cannot set a specific start date here.

UNTimeIntervalNotificationTrigger* trigger = [UNTimeIntervalNotificationTrigger triggerWithTimeInterval:(14*24*3600) repeats: YES];
request = [UNNotificationRequest requestWithIdentifier:identifier content:content trigger:trigger];

I've tried with WeekdayOrdinal for UNCalendarNotificationTrigger but that does not work exactly with fortnight duration always.

Is there any way I can schedule local UNUserNotification fortnightly from a specific day in future?

Answer 1

UNNotificationRequest does not provide anything to trigger fortnight recurring.

With UNCalendarNotificationTrigger you can only trigger following types of recurring:

weekly , daily , monthly , yearly

switch repeatType {
    case .daily:
        newComponents.hour = components.hour
        newComponents.minute = components.minute
        break
    case .weekly:
        newComponents.hour = components.hour
        newComponents.minute = components.minute
        newComponents.weekday = components.weekday
        break
    case .monthly:
        newComponents.hour = components.hour
        newComponents.minute = components.minute
        newComponents.day = components.day
        break
    case .none:
        newComponents.hour = components.hour
        newComponents.minute = components.minute
        newComponents.day = components.day
        newComponents.month = components.month
        newComponents.year = components.year
        break
    case .annually:
        newComponents.hour = components.hour
        newComponents.minute = components.minute
        newComponents.day = components.day
        newComponents.month = components.month
        break
    }

Although you can easily use EventKit to create events and alarms within those events with all such recurring options you want like the fortnight, quarterly, half-yearly etc.

I have created this code to create events with multiple recurring types:

let eventStore = EKEventStore()
    eventStore.requestAccess(to: .event, completion: { (granted, error) in
        if (granted) && (error == nil) {
            let event = EKEvent(eventStore: eventStore)
            event.title = "Countdown title"
            event.startDate = Date()
            event.notes = "Countdown is complete!"
            event.isAllDay = false

            event.calendar = eventStore.defaultCalendarForNewEvents

            var frequency : EKRecurrenceFrequency = EKRecurrenceFrequency.daily
            var interval = 1

            switch repeatType {
            case .daily:
                //Repeat every day
                frequency = EKRecurrenceFrequency.daily
                interval = 1
                break
            case .weekly:
                //Repeat every week
                frequency = EKRecurrenceFrequency.weekly
                interval = 1
                break
            case .biweekly:
                //Repeat every 2 weeks
                frequency = EKRecurrenceFrequency.weekly
                interval = 2
                break
            case .monthly:
                //Repeat every month
                frequency = EKRecurrenceFrequency.monthly
                interval = 1
                break
            case .quarterly:
                //Repeat every 3 months
                frequency = EKRecurrenceFrequency.monthly
                interval = 3
                break
            case .halfYearly:
                //Repeat every 6 months
                frequency = EKRecurrenceFrequency.monthly
                interval = 6
                break
            default:
                // Repeat every year
                frequency = EKRecurrenceFrequency.yearly
                interval = 1

            }
            let alarm : EKAlarm = EKAlarm(relativeOffset: TimeInterval(exactly: 0)!)
            event.addAlarm(alarm)

            if interval > 0 {
                event.addRecurrenceRule(EKRecurrenceRule(recurrenceWith: frequency, interval: interval, end: nil))
            }

            do {
                try eventStore.save(event, span: .thisEvent)
            } catch let error as NSError {
                print(error.localizedDescription)
                return
            }
        } else {
            print(error?.localizedDescription ?? "no error")
        }
    })

Please don't forget to import EventKit .

Answer 2

Try with triggerWithDateMatchingComponents method

Objective-C Example Code

NSDate *date = [NSDate dateWithTimeIntervalSinceNow:86400]; // You can set your date here.
NSDateComponents *triggerDate = [[NSCalendar currentCalendar]   
              components:NSCalendarUnitYear +
              NSCalendarUnitMonth + NSCalendarUnitDay +
              NSCalendarUnitHour + NSCalendarUnitMinute +
              NSCalendarUnitSecond fromDate:date];

UNCalendarNotificationTrigger *trigger = [UNCalendarNotificationTrigger triggerWithDateMatchingComponents:triggerDate repeats:NO];

Swift Example

let triggerDate = Calendar.current.date(byAdding: .day, value: 1, to: self)!
let trigger = UNCalendarNotificationTrigger(dateMatching: triggerDate, repeats: false)