//swift中的線程延時

 let time: TimeInterval = 1.0
            DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + time) {
                print("延時1秒執(zhí)行")
            }

//在主線程中延遲執(zhí)行某動作，不會卡主主線程，不影響后面的東做執(zhí)行

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3* NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

NSLog(@"%@", [NSThread currentThread]);

});

//在子線程中執(zhí)行某動作，不會卡主整個線程

dispatch_queue_t queue= dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3* NSEC_PER_SEC)), queue, ^{

NSLog(@"%@", [NSThread currentThread]);

});

//實現(xiàn)延遲，該線程本身在哪個線程中就再哪個線程中執(zhí)行

NSURL *url = [NSURL URLWithString:@"http://59320.jpg.com"];

[selfperformSelector:@selector(download:) withObject:url afterDelay:3];

//利用sleep實現(xiàn)延遲(不要用這個，會卡住主線程，即后面的動作不會執(zhí)行)

[NSThread sleepForTimeInterval:3];