cocos2d for iPhone

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1. 

   crmagicxxx
   Member

   I want to cache an Action in my global singleton, but the problem is that indicated action has sequence with CallFunc inside. The class in which I'd use that action is constantly allocated/deallocated (objects appearing and disappearing from scene), and the selector I use in CallFunc belongs to that class. So my singleton doesn't know the address of that selector in time of creation. Even if it could know it, I suppose that address is changing all the time because Class is deallocated and allocated again and again.

   I hope I was clear :) and somebody have some solution...

   Maybe it's even impossible to cache action with calling selector for class whose address is changing?

   Posted 2 years ago #
2. 

   Codemattic
   Moderator

   Maybe use a proxy object. It always stays the same, but you keep it informed of the latest real object to use (or nil if nothing is available.) The proxy passes the message on to the real object.

   If you arent sure what messages your proxy will have to handle ahead of time - check out NSObject's -forwardInvocation: message handling:

   http://developer.apple.com/iphone/library/documentation/cocoa/reference/Foundation/Classes/NSObject_Class/Reference/Reference.html#//apple_ref/doc/uid/20000050-forwardInvocation_

   Posted 2 years ago #
3. 

   crmagicxxx
   Member

   Ok, your suggestion looks good, but I am afraid it still looses the "cache" detail. For exmaple:

   @implementation SomeClass (allocated/deallocated all the time)
   
   -(void) selecorMethod {
       // anything here
   }
   
   -(void) methodInWhichSelectorIsCalled {
   	id action1 = [SomeAction...];
   	id action2 = [CallFunc actionWithTarget:self  selector:@selector(selecorMethod)];
   
   	// now make more actions, sequence, run final action on self
   }

   In this case I'd like to cache that final action. But the problem I see here is that selecorMethod will have different address every time SomeClass is allocated again. So cache would not be cache in full sense of that word because it'll have different parameters inside it. So if you change it in any way (like through invocations), final action will have totally different address every time. So it's not cached action at all.

   Please prove me wrong
   Thanks

   Posted 2 years ago #
4. 

   CJ
   Moderator

   I think selectors are essentially just names and can be called against any object.
   For example:
   @selector(myMethod:) when used inside ClassA is actually identical to @selector(myMethod:) inside unrelated ClassB.
   I think Obj-C determines at runtime how to route messages, so this is valid too:
   [aClassXInstance performSelector:@selector(myMethod:)] even if you haven't defined myMethod: on ClassX (though you'd get a crash at runtime since it's not defined on ClassX)

   So, caching the selector should not be an issue. But a proxy is probably required in your case to cache the target object.

   Hope I'm clear in my explanation.

   Posted 2 years ago #
5. 

   Codemattic
   Moderator

   "selecorMethod will have different address"

   self will have a different address, but selecorMethod is a selector and it will stay the same.

   Posted 2 years ago #
6. 

   crmagicxxx
   Member

   Ok, I understand both of you. I'll try and tell you the results...

   Posted 2 years ago #
7. 

   crmagicxxx
   Member

   Uh, it was my bad from the beginning. I somehow totally overlooked the "self" in CallFunc and for crashing blamed the @selector. Poor @selector, I suppose he is sad now

   Posted 2 years ago #

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