iPhone - 队列中的操作之间的延迟 [英] iPhone - a delay between operations in the queue

问题描述

我使用类似的东西向队列添加操作

I am adding operations to the queue using something like this

NSInvocationOperation *operation0 = [[NSInvocationOperation alloc] 
initWithTarget:self
selector:@selector(doStuff1) 
object:nil];

[queue addOperation:operation0];
[operation0 release];   


NSInvocationOperation *operation1 = [[NSInvocationOperation alloc] 
initWithTarget:self
selector:@selector(doStuff2) 
object:nil];

[queue addOperation:operation1];
[operation1 release];   


NSInvocationOperation *operation2 = [[NSInvocationOperation alloc] 
initWithTarget:self
selector:@selector(doStuff3) 
object:nil];

[queue addOperation:operation2];
[operation2 release];   

队列设置为一次只执行一个操作。所以它会毫不拖延地一个接一个地运行3种方法。这是一种添加一个小延迟的方法，比如每次操作之间的0.5秒或其他任何操作，所以不要运行

The queue is set to do just one operation at a time. So it will run the 3 methods without delay, one after another. Is that a way to add a small delay, lets say 0.5 seconds or whatever between each operation, so instead of running

doStuff1
doStuff2
doStuff3

队列会做什么

doStuff1
sleep for X seconds
doStuff2
sleep for X seconds
doStuff3

？

谢谢。

推荐答案

没有额外的代码，你不能确保您的NSOperations将以串行方式运行 - 如果Apple发布多处理器iOS设备，它将并行运行多个操作。首先，您应该在操作之间设置依赖关系链。我建议您使用NSOperation的 - （void）addDependency：（NSOperation *）操作来实现此目的。您也可以滚动自己的花式锁定代码...

Without extra code, you can't really guarantee that your NSOperations will run in serial - if Apple release a multiprocessor iOS device, it will run multiple operations in parallel. So firstly, you should set up the dependency chain between your operations. I would suggest that you achieve this using NSOperation's - (void)addDependency:(NSOperation *)operation. You could also roll your own fancy locking code...

然后，您可以在每个doStuff方法的末尾添加一个sleep（5）。如果您需要在doStuff方法之外进行睡眠，请创建一个睡眠NSOperation：

You can then add a sleep(5) to the end of each of your doStuff methods. If you need the sleep outside the doStuff methods, create a sleep NSOperation:

- (void)sleepOperationBody; {
sleep(0.5f);
}

NSInvocationOperation *operation1 = [[NSInvocationOperation alloc] 
initWithTarget:self
selector:@selector(sleepOperationBody) 
object:nil];

这就是说，如果不知道你需要发生什么，我想你或许只需要一个NSOperation结合了所有三个任务并在它们之间进行了睡眠。那当然是更简单的代码。

That said, without knowing in more detail what you need to happen, I think you perhaps just need one NSOperation that combines all three tasks and puts a sleep between them. That would certainly be simpler code.

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