[self performSelector:@selector(run)withObject:nilafterDelay:2.0];
//2秒後再調用self的run方法
dispatch_after(dispatch_time(DISPATCH_TIME_NOW,(int64_t)(2.0* NSEC_PER_SEC)),dispatch_get_main_queue(),^{
//2秒後執行這裏的代碼...
});
[NSTimer scheduledTimerWithTimeInterval:2.0target:selfselector:@selector(test)userInfo:nilrepeats:NO];