---
title: "SNRFetchedResultsController"
url: https://deallocatedobjects.com/posts/snrfetchedresultscontroller
author: Jake Marsh
published: 2011-11-27
updated: 2013-11-16
link: https://github.com/indragiek/SNRFetchedResultsController
topics: ["iOS Development", "Open Source"]
description: "SNRFetchedResultsController is a “port” (not exactly) of NSFetchedResultsController from iOS to OS X. It is not a drop in replacement for NSFetchedResultsController, but performs many of the same tasks in relation to managing results from a Core Data fetch and notifying a delegate when objects are…"
---

# SNRFetchedResultsController

By Jake Marsh, November 27, 2011. HTML: https://deallocatedobjects.com/posts/snrfetchedresultscontroller

This is a link post about https://github.com/indragiek/SNRFetchedResultsController

> `SNRFetchedResultsController` is a "port" (not exactly) of `NSFetchedResultsController` from iOS to OS X. It is not a drop in replacement for `NSFetchedResultsController`, but performs many of the same tasks in relation to managing results from a Core Data fetch and notifying a delegate when objects are inserted, deleted, updated, or moved in order to update the UI.

As someone who is primarily an iOS guy, having this class around makes the thought of doing some larger Mac OS X and AppKit-based stuff much more inviting.

Implementing it is this easy:

``` objc

NSFetchRequest *request = [[NSFetchRequest alloc] init];

request.entity = [NSEntityDescription entityForName:@"Car" inManagedObjectContext:context];
request.sortDescriptors = [NSArray arrayWithObjects:[NSSortDescriptor sortDescriptorWithKey:@"year" ascending:YES], nil];
request.predicate = [NSPredicate predicateWithFormat:@"wheels.@count != 0"];
request.fetchBatchSize = 20;

self.fetchedResultsController = [[SNRFetchedResultsController alloc] initWithManagedObjectContext:context fetchRequest:request];
self.fetchedResultsController.delegate = self;

NSError *error = nil;
[self.fetchedResultsController performFetch:&error];

if (error) {
    NSLog(@"Unresolved error: %@ %@", error, [error userInfo]);
}

```

``` objc

- (NSInteger) numberOfRowsInTableView:(NSTableView *)aTableView
{
    return [self.fetchedResultsController count];
}
- (id) tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex
{
    return [self.fetchedResultsController objectAtIndex:rowIndex];
}

```

``` objc

- (void) controller:(SNRFetchedResultsController *)controller didChangeObject:(id)anObject atIndex:(NSUInteger)index forChangeType:(SNRFetchedResultsChangeType)type newIndex:(NSUInteger)newIndex
{
    switch (type) {
        case SNRFetchedResultsChangeDelete:
            [self.tableView removeRowsAtIndexes:[NSIndexSet indexSetWithIndex:index] withAnimation:NSTableViewAnimationSlideLeft];
            break;
        case SNRFetchedResultsChangeInsert:
            [self.tableView insertRowsAtIndexes:[NSIndexSet indexSetWithIndex:newIndex] withAnimation:NSTableViewAnimationSlideDown];
            break;
        case SNRFetchedResultsChangeUpdate:
            [self.tableView reloadDataForRowIndexes:[NSIndexSet indexSetWithIndex:index] columnIndexes:[NSIndexSet indexSetWithIndex:0]];
            break;
        case SNRFetchedResultsChangeMove:
            [self.tableView removeRowsAtIndexes:[NSIndexSet indexSetWithIndex:index] withAnimation:NSTableViewAnimationSlideLeft];
            [self.tableView insertRowsAtIndexes:[NSIndexSet indexSetWithIndex:newIndex] withAnimation:NSTableViewAnimationSlideDown];
            break;
        default:
            break;
    }
}

```

`SNRFetchedResultsController` is created by [Indragie Karunaratne](http://twitter.com/#!/indragie). He has been rocking the Mac OS X open source stuff lately and this latest one doesn't disappoint.