GCD vs performSelectorInBackground/performSelectorOnMainThread

Question

I am new in ios development. I have following questions:

1. When we use GCD(dispatch_group_async, dispatch_async(dispatch_get_main_queue()...) and when we use per

Answer 1

Actually after iOS 4.0 I can't find any single reason to use performSelectorInBackground/onMainThread. If you need to do something in background, use GCD( or, better, NSOperationQueue which is built on top of GCD since 4.0 and gives greater flexibility with little overhead), but be sure not to create retain cycles when using blocks.