Pass data from NSOperation to next NSOperation

问题:

Is it possible to pass data from an NSOperation up the dependency chain to be used by the next NSOperation?

Thanks

Chris

回答1:

Yes. The current NSOperation can access it's dependancies via the dependencies method:

NSArray *myDependancies = [self dependencies];

It can then access whatever properties you wish on the previous operations and pull out any data it requires.

In a recent project I found that I needed to pass data along so often that I created a subclass of NSOperation that automatically carried forward an NSDictionary of data from one operation to the next.