cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   tutukun
   Member

   If i have a string 'A' to represent name of a function. Is there anyway i can check if a class contain function 'A'? I want to this while the app is running.

   something like

   if("function_nameA" in classA)
   [classA function_nameA]

   Thanks

   Posted 2 years ago #
2. 

   natanavra
   Member

   you could do this:

   if([myObject respondsToSelector@selector(myFunction)]) {
          [myObject myFunction];
   }

   Pretty useful when trying to call a function on a class but not being sure whether it's an enemy or a player...
   Hope this helps, Natan Avra.

   Posted 2 years ago #
3. 

   sunsu
   Member

   You can also do [myobject performSelector:@selector(myMethod)]. keep in mind you can also create a selector from a string.

   Posted 2 years ago #
4. 

   natanavra
   Member

   @sunsu I'm wondering (never tried before) but if the class doesn't contain the suggested selector, it would throw an exception, wouldn't it?
   So it's suggested to first check if it responds to a certain selector and only then perform it...
   Am I wrong?

   Posted 2 years ago #
5. 

   sunsu
   Member

   You are correct. It will throw an error if there isn't a method. Using the performSelector prevents you from having to create a big if-else mess after you do the "respondsToSelector". It also let's you import selectors from XML files and things if you use the stringToSelector tool.

   Posted 2 years ago #
6. 

   tutukun
   Member

   thx guys, im go give it a try.
   @sunsu: can u give me a example of creating selector from a string?

   Posted 2 years ago #
7. 

   natanavra
   Member

   You could try something like this:

   NSString *methodString = [NSString stringWithString:@"myMethod"];
   SEL methodSelector = NSSelectorFromString(methodString);
   [myObject performSelector:methodSelector];

   This should work I guess.
   ~ Natan Avra.

   Posted 2 years ago #

RSS feed for this topic

Reply

You must log in to post.