Question

I’ve some question regarding Objective C in Xcode 4.2.

How do I correctly call a class member method. For example if I had a class called MyClass with a method draw. At the moment i’m trying this.

MyClass *myclass;

myclass = [MyClass alloc];

[myclass draw];

I can’t be creating my class instance correctly because a breakpoint in the draw method is never reached.

I’m also curious as to where the main function calls occur in an Xcode 4.2 project. If I wanted to make a game with a function called setup where would I call setup?

Any help appreciated as i’m trying to familiarize with Xcode and Objective C.

Answer 1

You should send the init message to initialize the object:

MyClass *myclass = [[MyClass alloc] init];
[myclass draw];

A rarely used option is the new method, which is a combination of alloc and init:

MyClass *myclass = [MyClass new];
[myclass draw];

The latter is shorter, but unconventional as it can be confusing when using Objective-C++. Also see the NSObject class reference.

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For your setup method, you can set up things in the applicationDidFinishLaunching: method of your application delegate (or in the main function in a daemon or command line application). Xcode’s templates have the main function in a file called main.m.