Register to be notified about changes and keep your app up to date.
It’s possible for another process or app to modify the Calendar database while your app is running. If your app fetches calendar events or reminders, register to be notified about changes to the Calendar database to ensure the calendar and reminder information you display to the user is current.
Register for Notifications
Respond to Notifications
When you receive an
EKEvent notification, it’s possible the objects you’ve fetched—such as an
EKCalendar—have changed. The effect of the changes depends on whether an event was added, modified, or deleted:
If an event was added, it does not affect any of your previously fetched events or reminders, but the added event may fall within the date range of events you are displaying to the user.
Because your local data is often invalidated or incomplete when a change occurs in the Calendar database, you should refetch your current date range of events whenever you receive an
EKEvent notification. If you are modifying an event and do not want to refetch it unless it is absolutely necessary, call the
refresh method on the event. If the method returns
YES, you can continue to use the event; otherwise, you must refetch it.