How to implement re-ordering of CoreData records?

by

FetchedResultsController and its delegate are not meant to be used for user-driven model changes. See the Apple reference doc.
Look for User-Driven Updates part. So if you look for some magical, one-line way, there’s not such, sadly.

What you need to do is make updates in this method:

- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {
 userDrivenDataModelChange = YES;

 ...[UPDATE THE MODEL then SAVE CONTEXT]...

 userDrivenDataModelChange = NO;
}

and also prevent the notifications to do anything, as changes are already done by the user:

- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
 if (userDrivenDataModelChange) return;
 ...
}
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {
 if (userDrivenDataModelChange) return;
 ...
}
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
 if (userDrivenDataModelChange) return;
 ...
}

I have just implemented this in my to-do app (Quickie) and it works fine.

More Related Contents:

  1. Delete/Reset all entries in Core Data?
  2. Any way to pre populate core data?
  3. Unable to find specific subclass of NSManagedObject
  4. Core Data: Quickest way to delete all instances of an entity
  5. The model used to open the store is incompatible with the one used to create the store
  6. Sqlite File Location Core Data
  7. Core Data and iOS 7: Different behavior of persistent store
  8. Xcode NSManagedObject subclass contains optionals when they are marked as non-optional
  9. Xcode is looking for core data entity names with dot; not compiling
  10. Core Data – Failed to load optimized model at path
  11. How to store an image in core data
  12. NSFetchedResultsController v.s. UILocalizedIndexedCollation
  13. When should I use the various storage mechanisms in iOS?
  14. iPhone Core Data “Automatic Lightweight Migration”
  15. How to access CoreData model in today extension (iOS)
  16. Core Data: Do child contexts ever get permanent objectIDs for newly inserted objects?
  17. SwiftUI DatePicker Binding optional Date, valid nil
  18. Core Data in Swift: Only saving last object in a for loop
  19. Core Data multi thread application
  20. Xcode 6 iPhone Simulator Application Support location
  21. How come I can cast to NSManagedObject but not to my entity’s type?
  22. +entityForName: nil is not a legal NSManagedObjectContext parameter searching for entity name ‘Account”
  23. Storing UIColor object in Core Data
  24. How do I delete all objects from my persistent store in Core Data?
  25. How to get URL for a PHAsset? [duplicate]
  26. Accessing Core Data Stack in MVVM application
  27. How to properly group a list fetched from CoreData by date?
  28. Using Core Data, iCloud and CloudKit for syncing and backup and how it works together
  29. Implementing Fast and Efficient Core Data Import on iOS 5
  30. How to disable no inverse relationship warning for CoreData in Xcode 4.2?

Leave a Comment