Question

Yes I am a begginer. I am reading a book on cocos2d development. The author wrote this book using 0.99.4. In the book, it says to call a function that creates sprites and adds them to an array by using the following code: [self initSpiders];. But when I run this, I get a warning that says “‘Gamescene may not respond to’-resetSpiders'”. I am assuming that there is an updated way of doing this in the newer version of cocos2d. If there is, I would be thankful if someone could explain the proper way of going about this. If this is the correct way, then what am I doing wrong? Thanks in advance.

Answer 1

In objective-c, an object tells a message to do something:

[someObject doSomething];

Or with an argument:

[someObject doSomethingWithArgument:someValue];

The message you get from the compiler is telling you that the object (eg. “someObject”) does not understand what you are telling it to do (doSomething).

To make that compiler warning go away, check the following:

1. Did you #include the header file of the class your “someObject” is an instance of?
2. Does that header file in fact have the method you are calling? (including arguments?)

If you are calling a method you wrote, make sure you put that method in the header file. If you are calling a method that someone else wrote, or is part of the OS; make sure you include the header file, then perhaps find the method in the header file and copy/paste it into your code. This will make sure you get the EXACT method signature. These two are not the same:
[self generateSprites]; // note the capitol S
[self generatesprites]; // method names are case sensitive

If you need a better answer, you’ll need to post some of your code so that people can see what you’re doing wrong.