gistfile1.mm

/*
Error-free way to work with NSFetchedResultsController
*/

/**
 Delegate methods of NSFetchedResultsController to respond to additions, removals and so on.
 */

- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
	// The fetch controller is about to start sending change notifications, so prepare the table view for updates.
	[self.tableView beginUpdates];
    insertedSections = [NSMutableArray new];
    deletedSections = [NSMutableArray new];
}

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {
	
	UITableView *tableView = self.tableView;
	switch(type) {
			
		case NSFetchedResultsChangeInsert:
            if (![insertedSections containsObject:[NSNumber numberWithInteger:[newIndexPath section]]]) {
                [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
                //NSLog(@"Insert object to [%i; %i]", [newIndexPath section], [newIndexPath row]);
            }
			break;
			
		case NSFetchedResultsChangeDelete:
            if (![deletedSections containsObject:[NSNumber numberWithInteger:[indexPath section]]]) {
                [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
                //NSLog(@"Delete object from [%i; %i]", [indexPath section], [indexPath row]);
            }
			break;
			
		case NSFetchedResultsChangeUpdate:
			[self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
            //NSLog(@"Update object at [%i; %i]", [indexPath section], [indexPath row]);
			break;

		case NSFetchedResultsChangeMove:
            if (newIndexPath != nil) {
                [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
                [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            }
            else {
                [tableView reloadSections:[NSIndexSet indexSetWithIndex:indexPath.section] withRowAnimation:UITableViewRowAnimationFade];
            }
            //NSLog(@"Move object from [%i; %i] to [%i; %i]", [indexPath section], [indexPath row], [newIndexPath section], [newIndexPath row]);
			break;
	}
}

- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type {
	
	switch(type) {
			
		case NSFetchedResultsChangeInsert:
			[self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            [insertedSections addObject:[NSNumber numberWithInteger:sectionIndex]];
			break;
			
		case NSFetchedResultsChangeDelete:
			[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            [deletedSections addObject:[NSNumber numberWithInteger:sectionIndex]];
			break;
	}
}

- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
	// The fetch controller has sent all current change notifications, so tell the table view to process all updates.
    [self.tableView endUpdates];
    [insertedSections release];
    [deletedSections release];
}