scheduling a Thread after a Thread in iphone application

问题

I want to schedule a thread after a thread completion.

Is it possible ? How?

For example ( to specify my need )

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    // 1. response - schedule myThread 
    // 2. response - schedule a new thread which will be executed after myThread
    // 3. response - schedule a new thread which will be executed after second thread
    // .....
}

回答1:

If you use NSOperations you can use the addDependency: method to specify an operation's dependencies.

NSInvocationOperation will probably be useful to you if you go this route.

Edit: I just re-read the subject and you're on iPhone so you don't have blocks, but for reference, if you have blocks available, NSBlockOperation is even better.

Note that when using these methods to perform asynchronous operations (and assuming the code in them uses autorelease) you'll be responsible for instantiating an NSAutoreleasePool when your method starts running and releasing/draining it upon exit.

回答2:

(1) You can poll the threads isFinished property.

(2) You can register your dispatching/controlling object to receive the threads NSThreadWillExitNotification notification. For more precise control, you can subclass NSThread and to send a notification as the last act before the thread stops. Then in your controlling objects notification handler you can poll isFinished to make sure its done before launching the next thread.

See Thread Programming Guide and NSThread Class Guide.

来源：https://stackoverflow.com/questions/1639627/scheduling-a-thread-after-a-thread-in-iphone-application