问题
I'm trying to transform one method call into another dynamically (at runtime).
For instance, I'd like the following:
[obj foo]
to delegate to:
[obj getAttribute: @"foo"]
(I'd like to do this dynamically as I don't know ahead of time what those method names or attributes are going to be).
I see that there's a hook into:
- (id) forwardingTargetForSelector: (SEL) aSelector
That only seems to work for delegation, though, I want to keep the object as "self" and transform the method arguments.
Where should I look for this sort of behavior? Is it even possible in obj-c?
回答1:
You can use the method -forwardInvocation: for that. It takes a full NSInvocation object which represents the method call, and you can handle it however you wish. If you do this, you should also override -methodSignatureForSelector: to return the correct NSMethodSignature (required for -forwardInvocation: to work on unknown selectors). It's also recommended that you override -respondsToSelector: to declare that you can handle the selector in question.
来源：https://stackoverflow.com/questions/4630797/method-missing-like-functionality-in-objective-c-i-e-dynamic-delegation-at-run