Refresh NSManagedObjectContext

Question

I am writing a WatchKit extension for an iPhone application. I share Core Data using App Groups. This is working, the data is shared. When a new NSManagedObject

Answer 1

The simple way is just to have the app reload its data. Re-do any fetches so that you get the latest data from the persistent store.

If you want to make it more sophisticated, do something like this:

In the watch extension, for every new/changed/deleted object,

• Call objectID to get the NSManagedObjectID
• Convert the object ID to a string URIRepresentation
• Pass these strings in the MMWormhole message

In the app, when receiving the message,

• Use [NSPersistentStoreCoordinator managedObjectIDForURIRepresentation:] to convert the strings back to an NSManagedObjectID
• Use [NSManagedObjectContext existingObjectWithID:] to get the managed object corresponding to the object ID.

Now you know which objects need refreshing.