I am placing an NSFetchedResultsController into my code so I get that nice automatic sectioning of my table view data.
So I am running a test to make sure everything works properly. I have a single Book entity in my persistent store. I will first perform the fetch the old way, then I will try to use NSFetchedResultsController. The difference between the 2 blocks of code is just 2 lines.
Code without NSFetchedResultsController:
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:kBookEntityName inManagedObjectContext:self.managedObjectContext];
[request setEntity:entity];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"title" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[request setSortDescriptors:sortDescriptors];
[sortDescriptor release];
[sortDescriptors release];
//The following 2 lines will be replaced by the NSFetchedResultsController
NSMutableArray *mutableFetchResults = [[[self.managedObjectContext executeFetchRequest:request error:nil] mutableCopy] autorelease];
Book *result = (Book*)[mutableFetchResults objectAtIndex:0];
NSString* title = [result valueForKey:@"title"];
NSString* priority = [result valueForKeyPath:@"priority.name"];
[request release];
Now I substitute in the lines for the NSFetchedResultsController:
NSFetchedResultsController* fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"title" cacheName:@"BookList"];
Book *result = (Book*)[fetchedResultsController objectAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]];
Seems pretty cut and dry. The first code block properly fetches the single Book entity. The code with the NSFetchedResultsController, however, does not. Instead it returns nil.
My question is: Am I properly configuring the NSFetchedResultsController in this example?
(note, the fetchedObjects property of the NSFetchedResultsController is also nil)