eventkit-calendar

EventKit — Calendar & Reminders Create, read, and manage calendar events and reminders. Covers authorization, event and reminder CRUD, recurrence rules, alarms, and EventKitUI editors. Targets Swift 6.2 / iOS 26+. Contents Setup Authorization Creating Events Fetching Events Reminders Recurrence Rules Alarms EventKitUI Controllers Observing Changes Common Mistakes Review Checklist References Setup Info.plist Keys Add the required usage description strings based on what access level you need: Key Access Level NSCalendarsFullAccessUsageDescription Read + write events NSCalendarsWriteOnlyAccessUsageDescription Write-only events (iOS 17+) NSRemindersFullAccessUsageDescription Read + write reminders For apps also targeting iOS 16 or earlier, also include the legacy NSCalendarsUsageDescription / NSRemindersUsageDescription keys. Event Store Create a single EKEventStore instance and reuse it. Do not mix objects from different event stores. import EventKit let eventStore = EKEventStore ( ) Authorization iOS 17+ introduced granular access levels. Use the modern async methods. Full Access to Events func requestCalendarAccess ( ) async throws -> Bool { let granted = try await eventStore . requestFullAccessToEvents ( ) return granted } Write-Only Access to Events Use when your app only creates events (e.g., saving a booking) and does not need to read existing events. func requestWriteAccess ( ) async throws -> Bool { let granted = try await eventStore . requestWriteOnlyAccessToEvents ( ) return granted } Full Access to Reminders func requestRemindersAccess ( ) async throws -> Bool { let granted = try await eventStore . requestFullAccessToReminders ( ) return granted } Checking Authorization Status let status = EKEventStore . authorizationStatus ( for : . event ) switch status { case . notDetermined : // Request access break case . fullAccess : // Read and write allowed break case . writeOnly : // Write-only access granted (iOS 17+) break case . restricted : // Parental controls or MDM restriction break case . denied : // User denied -- direct to Settings break @unknown default : break } Creating Events func createEvent ( title : String , startDate : Date , endDate : Date , calendar : EKCalendar ? = nil ) throws { let event = EKEvent ( eventStore : eventStore ) event . title = title event . startDate = startDate event . endDate = endDate event . calendar = calendar ?? eventStore . defaultCalendarForNewEvents try eventStore . save ( event , span : . thisEvent ) } Setting a Specific Calendar // List writable calendars let calendars = eventStore . calendars ( for : . event ) . filter { $0 . allowsContentModifications } // Use the first writable calendar, or the default let targetCalendar = calendars . first ?? eventStore . defaultCalendarForNewEvents event . calendar = targetCalendar Adding Structured Location import CoreLocation let location = EKStructuredLocation ( title : "Apple Park" ) location . geoLocation = CLLocation ( latitude : 37.3349 , longitude : - 122.0090 ) event . structuredLocation = location Fetching Events Use a date-range predicate to query events. The events(matching:) method returns occurrences of recurring events expanded within the range. func fetchEvents ( from start : Date , to end : Date ) -> [ EKEvent ] { let predicate = eventStore . predicateForEvents ( withStart : start , end : end , calendars : nil // nil = all calendars ) return eventStore . events ( matching : predicate ) . sorted { $0 . startDate < $1 . startDate } } Fetching a Single Event by Identifier if let event = eventStore . event ( withIdentifier : savedEventID ) { print ( event . title ?? "No title" ) } Reminders Creating a Reminder func createReminder ( title : String , dueDate : Date ) throws { let reminder = EKReminder ( eventStore : eventStore ) reminder . title = title reminder . calendar = eventStore . defaultCalendarForNewReminders ( ) let dueDateComponents = Calendar . current . dateComponents ( [ . year , . month , . day , . hour , . minute ] , from : dueDate ) reminder . dueDateComponents = dueDateComponents try eventStore . save ( reminder , commit : true ) } Fetching Reminders Reminder fetches are asynchronous and return through a completion handler. func fetchIncompleteReminders ( ) async -> [ EKReminder ] { let predicate = eventStore . predicateForIncompleteReminders ( withDueDateStarting : nil , ending : nil , calendars : nil ) return await withCheckedContinuation { continuation in eventStore . fetchReminders ( matching : predicate ) { reminders in continuation . resume ( returning : reminders ?? [ ] ) } } } Completing a Reminder func completeReminder ( _ reminder : EKReminder ) throws { reminder . isCompleted = true try eventStore . save ( reminder , commit : true ) } Recurrence Rules Use EKRecurrenceRule to create repeating events or reminders. Simple Recurrence // Every week, indefinitely let weeklyRule = EKRecurrenceRule ( recurrenceWith : . weekly , interval : 1 , end : nil ) event . addRecurrenceRule ( weeklyRule ) // Every 2 weeks, ending after 10 occurrences let biweeklyRule = EKRecurrenceRule ( recurrenceWith : . weekly , interval : 2 , end : EKRecurrenceEnd ( occurrenceCount : 10 ) ) // Monthly, ending on a specific date let monthlyRule = EKRecurrenceRule ( recurrenceWith : . monthly , interval : 1 , end : EKRecurrenceEnd ( end : endDate ) ) Complex Recurrence // Every Monday and Wednesday let days = [ EKRecurrenceDayOfWeek ( . monday ) , EKRecurrenceDayOfWeek ( . wednesday ) ] let complexRule = EKRecurrenceRule ( recurrenceWith : . weekly , interval : 1 , daysOfTheWeek : days , daysOfTheMonth : nil , monthsOfTheYear : nil , weeksOfTheYear : nil , daysOfTheYear : nil , setPositions : nil , end : nil ) event . addRecurrenceRule ( complexRule ) Editing Recurring Events When saving changes to a recurring event, specify the span: // Change only this occurrence try eventStore . save ( event , span : . thisEvent ) // Change this and all future occurrences try eventStore . save ( event , span : . futureEvents ) Alarms Attach alarms to events or reminders to trigger notifications. // 15 minutes before let alarm = EKAlarm ( relativeOffset : - 15 * 60 ) event . addAlarm ( alarm ) // At an absolute date let absoluteAlarm = EKAlarm ( absoluteDate : alertDate ) event . addAlarm ( absoluteAlarm ) EventKitUI Controllers EKEventEditViewController — Create/Edit Events Present the system event editor for creating or editing events. import EventKitUI class EventEditorCoordinator : NSObject , EKEventEditViewDelegate { let eventStore = EKEventStore ( ) func presentEditor ( from viewController : UIViewController ) { let editor = EKEventEditViewController ( ) editor . eventStore = eventStore editor . editViewDelegate = self viewController . present ( editor , animated : true ) } func eventEditViewController ( _ controller : EKEventEditViewController , didCompleteWith action : EKEventEditViewAction ) { switch action { case . saved : // Event saved break case . canceled : break case . deleted : break @unknown default : break } controller . dismiss ( animated : true ) } } EKEventViewController — View an Event import EventKitUI let viewer = EKEventViewController ( ) viewer . event = existingEvent viewer . allowsEditing = true navigationController ? . pushViewController ( viewer , animated : true ) EKCalendarChooser — Select Calendars let chooser = EKCalendarChooser ( selectionStyle : . multiple , displayStyle : . allCalendars , entityType : . event , eventStore : eventStore ) chooser . showsDoneButton = true chooser . showsCancelButton = true chooser . delegate = self present ( UINavigationController ( rootViewController : chooser ) , animated : true ) Observing Changes Register for EKEventStoreChanged notifications to keep your UI in sync when events are modified outside your app (e.g., by the Calendar app or a sync). NotificationCenter . default . addObserver ( forName : . EKEventStoreChanged , object : eventStore , queue : . main ) { [ weak self ] _ in self ? . refreshEvents ( ) } Always re-fetch events after receiving this notification. Previously fetched EKEvent objects may be stale. Common Mistakes DON'T: Use the deprecated requestAccess(to:) method // WRONG: Deprecated in iOS 17 eventStore . requestAccess ( to : . event ) { granted , error in } // CORRECT: Use the granular async methods let granted = try await eventStore . requestFullAccessToEvents ( ) DON'T: Save events to a read-only calendar // WRONG: No check -- will throw if calendar is read-only event . calendar = someCalendar try eventStore . save ( event , span : . thisEvent ) // CORRECT: Verify the calendar allows modifications guard someCalendar . allowsContentModifications else { event . calendar = eventStore . defaultCalendarForNewEvents return } event . calendar = someCalendar try eventStore . save ( event , span : . thisEvent ) DON'T: Ignore timezone when creating events // WRONG: Event appears at wrong time for traveling users event . startDate = Date ( ) event . endDate = Date ( ) . addingTimeInterval ( 3600 ) // CORRECT: Set the timezone explicitly for location-specific events event . timeZone = TimeZone ( identifier : "America/New_York" ) event . startDate = startDate event . endDate = endDate DON'T: Forget to commit batched saves // WRONG: Changes never persisted try eventStore . save ( event1 , span : . thisEvent , commit : false ) try eventStore . save ( event2 , span : . thisEvent , commit : false ) // Missing commit! // CORRECT: Commit after batching try eventStore . save ( event1 , span : . thisEvent , commit : false ) try eventStore . save ( event2 , span : . thisEvent , commit : false ) try eventStore . commit ( ) DON'T: Mix EKObjects from different event stores // WRONG: Event fetched from storeA, saved to storeB let event = storeA . event ( withIdentifier : id ) ! try storeB . save ( event , span : . thisEvent ) // Undefined behavior // CORRECT: Use the same store throughout let event = eventStore . event ( withIdentifier : id ) ! try eventStore . save ( event , span : . thisEvent ) Review Checklist Correct Info.plist usage description keys added for calendars and/or reminders Authorization requested with iOS 17+ granular methods ( requestFullAccessToEvents , requestWriteOnlyAccessToEvents , requestFullAccessToReminders ) Authorization status checked before fetching or saving Single EKEventStore instance reused across the app Events saved to a writable calendar ( allowsContentModifications checked) Recurring event saves specify correct EKSpan ( .thisEvent vs .futureEvents ) Batched saves followed by explicit commit() EKEventStoreChanged notification observed to refresh stale data Timezone set explicitly for location-specific events EKObjects not shared across different event store instances EventKitUI delegates dismiss controllers in completion callbacks References Extended patterns (SwiftUI wrappers, predicate queries, batch operations): references/eventkit-patterns.md EventKit framework EKEventStore EKEvent EKReminder EKRecurrenceRule EKCalendar EventKit UI EKEventEditViewController EKCalendarChooser Accessing the event store Creating a recurring event