NSFetchedResultsController didn't return data
- by Dmitry Kochkin
Hello!
I get stuck in some problem and after 2 days of seeking I've found solution but didn't get idea why does it work.
First, I'm initialized NSFetchedResultsController using following code (it look like a lot of automatically generated):
- (NSFetchedResultsController *)fetchedResultsController {
if (fetchedResultsController != nil)
return fetchedResultsController;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Profile"
inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setFetchBatchSize:20];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"lastName" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc]
initWithFetchRequest:fetchRequest
managedObjectContext:self.managedObjectContext
sectionNameKeyPath:nil
cacheName:@"Root"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
//[aFetchedResultsController performFetch:&error];
[aFetchedResultsController release];
[fetchRequest release];
[sortDescriptor release];
[sortDescriptors release];
return fetchedResultsController;
}
Have a look at commented string - there wasn't any of these strings and when I asked for data - I didn't get any (and it was there!). When I've uncommented that line, it starts work. Seems evident, but all examples I saw before hadn't that line. And they work. How can it be? I just want to know what am I doing wrong.
