Deleting reminders from calendar in Swift - ios

Question

I use the following function to retrieve my calendar:
func retrieveCalendar() -> EKCalendar? {
appDelegate = UIApplication.sharedApplication().delegate
as? AppDelegate
var myCalendar: EKCalendar?
let calendars = appDelegate!.eventStore!.calendarsForEntityType(EKEntityTypeReminder) as! [EKCalendar]
let filteredCalendars = calendars.filter {$0.title == "MedicalCalendar"}
if filteredCalendars.isEmpty {
println("could not find reminder calendar 'MedicalCalendar'")
return nil
} else {
myCalendar = filteredCalendars[0]
return myCalendar!
}
}
However, anytime I add new events to the calendar I'd like to check if they already exist there. I figured out that the easiest approach would be to delete all reminders and load new ones again. I tried:
self.retrieveCalendar()?.reset()
But it does not work. How can I remove reminders from calendar?(either one at a time or all of them at once)

Answer 1

To check reminders you have to call the method fetchRemindersMatchingPredicate() in conjunction with predicateForRemindersInCalendars or predicateForIncompleteRemindersWithDueDateStarting:ending:calendars: or predicateForCompletedRemindersWithCompletionDateStarting:ending:calendars:
For example if you want to delete all expired reminders in the past until now, use something like this
assumed properties:
var calendar : EKCalendar // current calendar
let eventStore : EKEventStore // current event store
code
func removeExpiredReminders() {
let pastPredicate = eventStore.predicateForIncompleteRemindersWithDueDateStarting(nil, ending:NSDate(), calendars:[calendar])
eventStore.fetchRemindersMatchingPredicate(pastPredicate) { foundReminders in
let remindersToDelete = !foundReminders.isEmpty
for reminder in foundReminders as! [EKReminder] {
self.eventStore.removeReminder(reminder, commit: false, error: nil)
}
if remindersToDelete {
self.eventStore.commit(nil)
}
}
}
in the loop you can check for further conditions