Blocks instead of performSelector:withObject:afterDelay:

Question

I often want to execute some code a few microseconds in the future. Right now, I solve it like this:

- (void)someMethod
{
    // some code
}

And this:

[self performSelector:@selector(someMethod) withObject:nil afterDelay:0.1];

It works, but I have to create a new method every time. Is it possible to use blocks instead of this? Basically I'm looking for a method like:

[self performBlock:^{
    // some code
} afterDelay:0.1];

That would be really useful to me.

Answer 1

There's no built-in way to do that, but it's not too bad to add via a category:

@implementation NSObject (PerformBlockAfterDelay)

- (void)performBlock:(void (^)(void))block 
          afterDelay:(NSTimeInterval)delay 
{
    block = [[block copy] autorelease];
    [self performSelector:@selector(fireBlockAfterDelay:) 
               withObject:block 
               afterDelay:delay];
}

- (void)fireBlockAfterDelay:(void (^)(void))block {
    block();
}

@end

Credit to Mike Ash for the basic implementation.