Objective-C delay action with blocks

use dispatch_after:

double delayInSeconds = 2.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
    //code to be executed on the main queue after delay
    [self doSometingWithObject:obj1 andAnotherObject:obj2];
});