iphone ios running in separate thread

Question

What is the best way to run code on a separate thread? Is it:

[NSThread detachNewThreadSelector: @selector(doStuff) toTarget:self withObject:NULL]; 

Or:

    NSOperationQueue *queue = [NSOperationQueue new]; NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self                                                                         selector:@selector(doStuff:)                                                                           object:nil; [queue addOperation:operation]; [operation release]; [queue release]; 

I've been doing the second way but the Wesley Cookbook I've been reading uses the first.

Answer 1

In my opinion, the best way is with libdispatch, aka Grand Central Dispatch (GCD). It limits you to iOS 4 and greater, but it's just so simple and easy to use. The code to do some processing on a background thread and then do something with the results in the main run loop is incredibly easy and compact:

dispatch_async( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{     // Add code here to do background processing     //     //     dispatch_async( dispatch_get_main_queue(), ^{         // Add code here to update the UI/send notifications based on the         // results of the background processing     }); }); 

If you haven't done so already, check out the videos from WWDC 2010 on libdispatch/GCD/blocks.