Looking for a way to present notification on even & odd days

Question

I'm looking for a way to present notifications on even (2,4,6,8,10,12...) & odd (1,3,5,7,9,11...) days.

I did something similar in reminders:

/// Creates a reminder
func create(_ title: String, isOddDays: Bool, hour: Int, minute: Int) {
    let dueDate = Date()
    let gregorian = Calendar(identifier: .gregorian)
    
    let daysOfTheMonth: [NSNumber]
    if isOddDays {
        daysOfTheMonth = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31]
    } else {
        daysOfTheMonth = [2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30]
    }
    
    let rule = EKRecurrenceRule(
        recurrenceWith: .monthly,
        interval: 1,
        daysOfTheWeek: nil,
        daysOfTheMonth: daysOfTheMonth,
        monthsOfTheYear: nil,
        weeksOfTheYear: nil,
        daysOfTheYear: nil,
        setPositions: nil,
        end: nil
    )
    
    guard let reminder: EKReminder = self.setUpReminder(with: title, priority: 0) else {
        return
    }
    
    reminder.dueDateComponents = gregorian.dateComponents([.day, .month, .year, .hour, .minute, .second], from: dueDate)
    reminder.addRecurrenceRule(rule)
    
    let todayDateComponents = gregorian.dateComponents([.day, .month, .year], from: Date())
    let day: Int = isOddDays ? 1 : 2
    let month: Int = todayDateComponents.month!
    let year: Int = todayDateComponents.year!
    
    let absoluteDate = Date.create(day: day, month: month, year: year, hour: hour, minute: minute, second: 0)
    
    let alarm = EKAlarm(absoluteDate: absoluteDate)
    reminder.addAlarm(alarm)
    
    UserDefaults.standard.set(reminder.calendarItemIdentifier, forKey: ReminderStoreManager.reminderDefaultsKey)
    
    self.saveReminder(reminder)
}

I want to do something similar with local notifications in order to send an acknowledgment back to the server.

EDIT: Screenshot added.

You can do the same thing with EKEvent. It has a *open URL* alarm type. Attach a script (AppleScript or Swift) to the alarm which creates and delivers the notification at the moment the alarm fires. — vadian, Nov 10 '22 at 08:45
Thanks, but that's too complicated since I need to remove reminders when the user removes the app from the device. — Idan Moshe, Nov 10 '22 at 12:09
Recommend to have a read here: https://developer.apple.com/documentation/usernotifications/scheduling_a_notification_locally_from_your_app — invzbl3, Nov 15 '22 at 21:48

score 2 · Accepted Answer · answered Nov 14 '22 at 13:53

Apparently I can use DateComponents without month & year and It will do the rest:

private func scheduleEveryTwoDaysNotification(prefix: String, isOddDay: Bool, title: String, triggerDate: Date) {
    let triggerDateComponents = Calendar.current.dateComponents([.day, .month, .year, .hour, .minute], from: triggerDate)
    
    guard let hour = triggerDateComponents.hour, let minute = triggerDateComponents.minute else {
        return
    }
    
    let days: [Int]
    if isOddDay {
        days = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31]
    } else {
        days = [2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30]
    }
    
    for day in days {
        let content = UNMutableNotificationContent()
        content.title = title
        content.sound = .default
        
        var components = DateComponents()
        components.day = day
        components.hour = hour
        components.minute = minute
        components.second = 0
        
        
        let calendarTrigger = UNCalendarNotificationTrigger(dateMatching: components, repeats: true)
        let identifier: String = "\(prefix).\(day)"
        let request = UNNotificationRequest(identifier: identifier, content: content, trigger: calendarTrigger)
        
        UNUserNotificationCenter.current().add(request) { (error) in
            if let error {
                debugPrint(#fileID, #function, error)
            } else {
                debugPrint(#function, request)
            }
        }
    }
}

score 0 · Answer 2 · answered Nov 10 '22 at 13:11

0

Something like:

import Foundation

func isThisAnEvenDay() -> Bool {
    Calendar.current.component(.day, from: Date()) % 2 == 0
}

print(isThisAnEvenDay())

Didn't work for you? Then you present your notification immediately, without the need to schedule ahead.

Don't know if is something like this you are looking for.

answered Nov 10 '22 at 13:11

Allan Garcia

550
3
16

Thanks but the whole idea is to schedule ahead the notifications like the reminders. – Idan Moshe Nov 10 '22 at 13:44
Use range and the _module_ operator `(1...31).forEach`... – Allan Garcia Nov 10 '22 at 13:50

Looking for a way to present notification on even & odd days

2 Answers2