👀 Views: 412 💬 Answers: 1 📅 Created: 2025-08-31

core-data nsfetchedresultscontroller ios objective-c Objective-C

I'm wondering if anyone has experience with Quick question that's been bugging me - I've been banging my head against this for hours. I'm working on a project and hit a roadblock. I'm having trouble with my implementation of `NSFetchedResultsController` to manage updates to a Core Data entity in my iOS app (targeting iOS 16). I have set up the `NSFetchedResultsController` correctly and am observing changes to a `NSManagedObjectContext`. However, when I perform updates on my Core Data objects, the `controllerDidChangeContent:` delegate method is not being called consistently. Sometimes, the changes reflect immediately in my UI, but other times, they seem to get lost or not trigger the necessary updates. Here's a snippet of how I've set up the `NSFetchedResultsController`: ```objc self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil]; self.fetchedResultsController.delegate = self; NSError *error = nil; if (![self.fetchedResultsController performFetch:&error]) { NSLog(@"Unresolved error %@, %@", error, error.userInfo); } ``` I've also implemented the delegate method as follows: ```objc - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { [self.tableView reloadData]; } ``` I've verified that the delegate is being set and that `performFetch:` runs without issues. The context is saved correctly, and I use the following method to save changes: ```objc - (void)saveContext { NSManagedObjectContext *managedObjectContext = self.persistentContainer.viewContext; if (managedObjectContext.hasChanges) { NSError *error = nil; if (![managedObjectContext save:&error]) { NSLog(@"Unresolved error %@, %@", error, error.userInfo); } } } ``` However, I've noticed that if I trigger multiple updates in a short period (like saving changes to multiple objects quickly), the changes sometimes do not trigger the `controllerDidChangeContent:` method properly. I also get intermittent messages like `NSManagedObjectContext: The operation couldn’t be completed. (Cocoa error 134110.)` in the debug console which I suspect might be related but I’m unsure how to address this. Any insights or suggestions on how to ensure that the UI updates reliably when the Core Data context changes would be greatly appreciated. What's the best practice here? Any help would be greatly appreciated! I'm using Objective-C 3.11 in this project. Am I approaching this the right way?