Question

I’ve an iOS project where I’m trying to use CoreData.

In my model, I’ve two class ChildA and ChildB who inherit from ParentClass.

In my UITableViewController, I can easily get all objects with:

NSEntityDescription *entity = [NSEntityDescription entityForName:@"ParentClass" inManagedObjectContext:self.managedObjectContext];

What I’m trying to achieve now is to group results by Classname. But I’ve no idea how to achieve that in my NSFetchedResultsController for the param sectionNameKeyPath

NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"?????" cacheName:@"Master"];

The result I want to use in my UITableView should look something like

ChildA
   Obj1
   Obj2
   Obj3
   ...
ChildB
   Obj4
   Obj5
   Obj6
   ...

Thanks in advance

Answer 1

I’ve found a possible way to achieve that…

I declared two NSFetchedResultsController in my UITableViewController

@interface MMPOITableViewController : UITableViewController <NSFetchedResultsControllerDelegate>
@property (strong, nonatomic) NSFetchedResultsController *childAFetchedResultsController;
@property (strong, nonatomic) NSFetchedResultsController *childBFetchedResultsController;
@end

The first one is responsible to manage objects of class ChildA and the second one is responsible to manage objects of class ChildB.

Then I managed to use childAFetchedResultsController or childBFetchedResultsController depends on the current section.

Hope it’ll help someone else 😉