Making changes to Core Data fetched array

Question

Here's what I have:

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription 
                               entityForName:@"NoteObject" inManagedObjectContext:appDelegate.managedObjectContext];

[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(parentNoteId == %@) AND (noteId!=rootNoteId)", appDelegate.currentNoteId];
[fetchRequest setPredicate:predicate];
NSError *error;

[appDelegate.arrayOfNotes setArray:[appDelegate.managedObjectContext executeFetchRequest:fetchRequest error:&error]];

NoteObject *note=[appDelegate.arrayOfNotes objectAtIndex:0];
[note.arrayOfTags addObject:someObject];

NSManagedObjectContext *context = [appDelegate managedObjectContext];
if (![context save:&error]) {
    NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
}

The fetch works fine, and adding an object to the arrayOfTags works and reflects in the UI. However, when I exit the app and come back, the arrayOfTags is missing the one that I added (but it has the other two, so I know the array is working properly). It's not saving for some reason.

(The NoteObject is a subclass of NSManagedObject, and arrayOfTags is a transformable property of the entity.)

Am I doing something wrong here?

Edit: Here's how I add a new note, which saves just fine, even with the arrayOfTags, and everything is saved when I exit the app and come back in.

NSManagedObjectContext *context = [appDelegate managedObjectContext];
NSEntityDescription *noteEntity = [[appDelegate.managedObjectModel entitiesByName] objectForKey:@"NoteObject"];
NoteObject *tempNote = [[NoteObject alloc] initWithEntity:noteEntity insertIntoManagedObjectContext:context];
[tempNote.arrayOfTags addObject:@"tag1"];
NSError *error;
        if (![context save:&error]) {
            NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
        }

It's only when I make changes that it's not saved properly..

Just a string..I'm not sure yet, but I think my problem might be that I'm not using a fetchedResultsController — Snowman
– Snowman, Commented Mar 4, 2012 at 18:09
It seems more likely to be a problem in your arrayOfTags implementation - can you include more detail about that? — jrturton
– jrturton, Commented Mar 4, 2012 at 18:13

Community · Accepted Answer · 2017-05-23 10:34:51Z

0

Did you mean you are using a Transformable attribute? Does this help: Core Data saving problem: can't update transformable attribute (NSArray)

edited May 23, 2017 at 10:34

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answered Mar 4, 2012 at 19:03

elprl

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1 Comment

Snowman Over a year ago

Yes this is the same problem. I dont understand his solution though. What exactly did he do?

Snowman · Accepted Answer · 2012-03-05 21:26:31Z

0

Turns out all I had to do was re-set the array after making changes to it:

NoteObject *tempNote = [[NoteObject alloc] initWithEntity:noteEntity insertIntoManagedObjectContext:context];
[tempNote.arrayOfTags addObject:@"tag1"];

[tempNote setArrayOfTags:tempNote.arrayOfTags]; //this is the magic line

NSError *error;
if (![context save:&error]) {
       NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
}

answered Mar 5, 2012 at 21:26

Snowman

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