Question

I use this code throughout my project to update the title of my UIBarButtonItem.

In this particular class, I have an NSFetchedResultsController which I want to to get the count for to set as the button’s title.

I am calling this code in ViwDidLoad but it seems as though it is being called before the fetch, therefore the count is always 0. I tried putting it at the end of the Fetch delegate method, but that didn’t help either. Any ideas? When I NSLog the count in the fetch delegate method, it is correct.

self.myBarButton.title = [NSString stringWithFormat: @"%i count", [fetchedResultsController.fetchedObjects count]];

viewDidLoad

- (void)viewDidLoad
{
    [super viewDidLoad];

    if (managedObjectContext == nil) 
    { 
        self.managedObjectContext = [(TestAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; 
    }

    NSSet *filteredFromSession=[selectedSession.property filteredSetUsingPredicate:[NSPredicate predicateWithFormat: @"name == %@",name]];
    if ([filteredFromSession count] > 0)
    {
        self.exercise = [filteredExercisesFromSession anyObject];
    }
    self.setLabel.title = [NSString stringWithFormat: @"%i sets", [fetchedResultsController.fetchedObjects count]];
}

Answer 1

It’s most probable that at the time you do this,

self.setLabel.title = [NSString stringWithFormat: @"%i sets", [fetchedResultsController.fetchedObjects count]];

fetchedResultsController is nil.

If you’ve a getter method defined for fetchedResultsController and have declared it as a property, I suggest you do the fetch before your line above,

NSError * error;
if (![self.fetchedResultsController performFetch:&error]) {
    // Error
}

Basically ensure that the fetch is completed prior to setting the title. Once you do this, you might want to remove the fetch from the place you’re doing right now.