ios中模拟延时的几种方法

- (void)delay1

{

    // 延迟执行不要用sleep，坏处：卡住当前线程

    [NSThread sleepForTimeInterval:3];

    NSLog(@"操作");

}

 

 

- (void)delay2

{

    // 一旦定制好延迟任务后，不会卡主当前线程

    [self performSelector:@selector(download:) withObject:@"http://美女.jpg" afterDelay:3];

}

 

- (void)delay3

{

    // 3秒后回到主线程执行block中的代码

    dispatch_queue_t queue = dispatch_get_main_queue();

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

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

    });

}

 

 

- (void)delay4

{

    // 3秒后自动开启新线程 执行block中的代码

    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(@"------task------%@", [NSThread currentThread]);

    });

}

 

 

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