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Editorial Team
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Asked: 2026-05-20T05:13:09+00:00

I’m using core data and NSFetchedResultsController in an app, for feeding a UIViewTable with

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I’m using core data and NSFetchedResultsController in an app, for feeding a UIViewTable with Car objects. I have a button that, when tabbed, takes the app to another view when the user can add a new Car. The problem I have is that even if the user doesn’t create the car in the second view, it’s added to the table. If I restart the application, the Car wasn’t added to the DB.

This is related to the fact that I create an instance of the Car in the second view, in the viewDidLoad method, using something like this:

    car = [NSEntityDescription insertNewObjectForEntityForName:@"Car" 
                                  inManagedObjectContext:context];

This is added even if I don’t save the context.

I tried to delete the object when the second view is about to be closed, using this:

[context deleteObject:car];

This partially works. The car is not added to the table in the first page, but looks like the indexes of the data source are altered. If I scroll all the way down I got this error:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[_PFBatchFaultingArray objectAtIndex:]: index (9) beyond bounds (9)'

Any ideas will be appreciated.

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1 Answer

  1. Editorial Team

    First, try delaying the insertion of the new object when the user commits the change.

    Only if it’s not appropriate:

    When the context has changed, NSFetchedResultsController is automatically informed to modify its data passed to the table view controller. However, the table view itself is not modified, so you have to update the table view by yourself.

    That’s why NSFetchedResultsController has a delegate object (conforming to NSFetchedResultsControllerDelegate protocol) which is responsible to update the table view.

    For example, in CoreDataBooks sample project, you will see delegate methods of this protocol in RootViewController class. The most related delegate method is controller: didChangeObject: atIndexPath: forChangeType: newIndexPath:. You may probably want to do something like the following:

    if (changeType == NSFetchedResultsChangeDelete) {
    [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];  
}
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