Beginning Core Data - Part 19: Fetched Results | Ray Wenderlich

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Hello, I’ve seen your priceless tutorial videos for CoreData and I’m a big fan of yours :slight_smile:

BTW, I have a question for this last tutorial lecture.
Do you have any sample project for this course that implements insertion/deletion Friend objects using NSFetchedResultsControllerDelegate in MainViewController? I’ve tried to implement this, but this is quite hard for me due to sections .

When I implement insertion/deletion using NSFetchedResultsControllerDelegate and run the app, it crashes when I add a new friend object :frowning: I have no idea why this crash occurs. Do you have an idea or reference that I can refer?

This is the code for insertion/deletion a friend object using NSFetchedResultsControllerDelegate:

func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
        switch type {
        case .insert:
            guard let indexPathForInsertion = newIndexPath else {
                return
            }
            if indexPathForInsertion.section > collectionView.numberOfSections - 1 {
                let indexSet = IndexSet(integer: indexPathForInsertion.section)
                collectionView.insertSections(indexSet)
                collectionView.insertItems(at: [indexPathForInsertion])
            }
        case .delete:
            guard let indexPathForDeletion = indexPath else {
                return
            }
            if collectionView.numberOfItems(inSection: indexPathForDeletion.section) == 1 {
                collectionView.deleteSections(IndexSet(integer: indexPathForDeletion.section))
            }
            else {
                collectionView.deleteItems(at: [indexPathForDeletion])
            }
        case .move, .update:
            break
        }
    }

And the error message is:
error: Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. -[UICachedDeviceRGBColor compare:]: unrecognized selector sent to instance 0x600000261200 with userInfo (null) CoreData: error: Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. -[UICachedDeviceRGBColor compare:]: unrecognized selector sent to instance 0x600000261200 with userInfo (null)