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iosrealm

Realm database - Notification when deleting an object

My question is simple: Is there some way for an instance of an object to be notified when it's about to get deleted?

I have a case where I have a property that is the path to an image stored on disk. I would like to delete this image whenever a realm object of that type is deleted.

Solution

  • If you prefer not to use KVO, you can take advantage of Realm's Object Notifications.

    A brief example would be:

    var token: NotificationToken?
token = yourRealmObject.addNotificationBlock { change in
    switch change {
    case .change(let properties):
        print("Object has changed")
    case .error(let error):
        print("An error occurred: \(error)")
    case .deleted:
        print("The object was deleted.")
    }
}

    just make sure to retain a strong reference to the token object since your notification block will be automagically unsubscribed by Realm as soon as it is released.