iOS开发-延迟执行

有时候,希望某段代码,某个时间在一定时间后执行,这时候就要用到延迟执行。

常见的方法有以下几种:

    [self performSelector:@selector(scale_2) withObject:nil afterDelay:0.5f];

-(void)scale_2
{
    UIImageView *round_2 = [[UIImageView alloc]initWithFrame:CGRectMake(105, 210, 20, 20)];
    round_2.image = [UIImage imageNamed:@"round_"];
    [splashView addSubview:round_2];
    [self setAnimation:round_2];
}

@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

void RunBlockAfterDelay(NSTimeInterval delay, void (^block)(void))
{

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_SEC*delay),
      dispatch_get_current_queue(), block);

}

[UIView animateWithDuration:0.0 delay:5.0 options:UIViewAnimationOptionAllowUserInteraction animations:^{

} completion:^(BOOL finished) {

    //do stuff here

}];

iOS开发-延迟执行

原文：http://blog.csdn.net/hitwhylz/article/details/19078039