Ejecutar un bloque de código con un pequeño delay.

gistfile1.m

// NSObject+PWObject.h
#import <Foundation/Foundation.h>

@interface NSObject (PWObject)

- (void)performBlock:(void (^)(void))block afterDelay:(NSTimeInterval)delay;

@end

/* NSObject+PWObject.m */
@implementation NSObject (PWObject)

- (void)performBlock:(void (^)(void))block afterDelay:(NSTimeInterval)delay
{
    int64_t delta = (int64_t)(1.0e9 * delay);
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, delta), dispatch_get_main_queue(), block);
}

@end


// Para ejecutarlo desde cualquier clase.
#import "NSObject+PWObject.h"

[self performBlock:^{
        
        NSLog("bloque ejecutado");
        
    } afterDelay:1.0];