CODEWITHSUNDEEP
objective-ccocos2d-iphone
Saturn
Saturn

Reputation: 18149

When to define methods on interface and when not to?

I'm using a Objective-C framework for game development called Cocos2d-iphone.

This is how I create a button-graphic in the game:

CCMenuItemImage *battle;
    battle = [CCMenuItemImage itemFromNormalImage:@"BattleFightOption1.png" selectedImage:@"BattleFightOption2.png"
                                           target:self selector:@selector(battleFightOption)];

Basically, when the user clicks the button, method battleFightOption runs.

But I wonder, I never did define battleFightOption in the interface.. so, my question is: when is it necessary to define a method in the interface, and when is it not?

Upvotes: 1

Views: 84

Answers (3)

Pontus Granström
Pontus Granström

Reputation: 1089

When you use a selector like @selector(methodName:), methodName: is called dynamically at runtime. The compiler doesn't have to know where it is, and doesn't check that the method exists when you compile.

However, it is still a good idea to declare it privately, which is generally done by putting an unnamed category at the top of the .m file (generally referred to as a class extension):

#import "Class.h"

@interface Class ()

- (void)privateMethod;

@end

@implementation Class
...

Upvotes: 1

Joe
Joe

Reputation: 57179

Anything that you intend to be public, called outside of the class, should be defined in the interface. If you are going to only use @selector(battleFightOption) you really do not need to define the method anywhere but I would recommend that you add a definition in the class extension just as you would any other private method.

Upvotes: 0

albertamg
albertamg

Reputation: 28572

In short, every method that is meant to be used from outside the class must be declared in the interface; methods that are internal to the class implementation are omitted. The latter are typically declared in a class extension.

Upvotes: 1

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