Which technique to use for creating private methods in Obj-C ?

Question

When I want to create private methods in Objective-C, what should I use?
1) The well known categories technique.
2) @private directive.
(I'm doing iOS development).

Answer 1

@private is for ivars, not for methods. Just create a class extension at the top of your .m file and put the private methods there. It looks something like

@interface MyClass () // note the empty parens
- (void)onePrivateMethod;
- (void)twoPrivateMethod;
@end

@implementation MyClass
// implement everything
@end