Objective-C method 'controller:didChangeObject:atIndexPath:forChangeType:newIndexPath

Question

Objective-C method 'controller:didChangeObject:atIndexPath:forChangeType:newIndexPath:' provided by method 'controller(:didChangeObject:atIndexPath:forChangeType:newIndexPath:)' conflicts with optional requirement method 'controller(:didChangeObject:atIndexPath:forChangeType:newIndexPath:)' in protocol 'NSFetchedResultsControllerDelegate'

func controller(controller: NSFetchedResultsController, didChangeObject anObject: NSManagedObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
    if self.collectionView?.window == nil {
        return
    }

    let change = NSMutableDictionary()

    switch(type)
    {
    case .Insert:
        change[NSNumber(unsignedLong:type.rawValue)] = newIndexPath
    case .Delete:
        change[NSNumber(unsignedLong:type.rawValue)] = indexPath
    case .Update:
        change[NSNumber(unsignedLong:type.rawValue)] = indexPath
    case .Move:
        change[NSNumber(unsignedLong:type.rawValue)] = NSArray(objects: indexPath!, newIndexPath!)
    default:
        break
    }
    self.objectChanges?.addObject(change)
}

Answer 1

It looks like the proper method signature is:

func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {

}

Any easy way to fix these problems is to allow Xcode to autocomplete the method signature. Then, replace your method's signature with the auto generated signature. For this, you just need to type controller when defining a method to see the list of all methods that match.