Question

I have a core data application which displays a list of custom objects, each representing theatrical productions.

Each show object has a bunch of properties – name, logo, opening date, show type.

I can retrieve them fine, and sort by type just fine – but I would like each show type to be its own section in the table.

I don’t know ahead of time how many show types will be represented in the result set, so I don’t know initially what the numberofsections should be.

So I guess the question is – how would I go about dividing the result set into sections grouped by type?

Currently I’m doing this:

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Show" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setFetchBatchSize:20];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"type" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];

[fetchRequest setSortDescriptors:sortDescriptors];

// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Root"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;

Answer 1

I would write numberOfSections method so that it dynamically checks for the number of types. Then, whenever a new type rolls in, just do a [tableView reloadData];