You will want to declare a delegate protocol for your class. An example of a delegate protocol and interface for class Foo might
look like this:
@class Foo;
@protocol FooDelegate <NSObject>
@optional
- (BOOL)foo:(Foo *)foo willDoSomethingAnimated:(BOOL)flag;
- (void)foo:(Foo *)foo didDoSomethingAnimated:(BOOL)flag;
@end
@interface Foo : NSObject {
NSString *bar;
id <FooDelegate> delegate;
}
@property (nonatomic, retain) NSString *bar;
@property (nonatomic, assign) id <FooDelegate> delegate;
- (void)someAction;
@end
Don't forget to synthesize your properties in the @implementation.
What this code did was declare a protocol called FooDelegate; a class that conforms to this protocol would be declared like @interface
SomeClass : SuperClass <FooDelegate> {}. Because this class conforms to the protocol FooDelegate,
it now gets to implement the methods underFooDelegate (to
require that these be implemented, use @required instead
of @optional).
The last step is for a Foo object
to be instantiated in the class that conforms to FooDelegate,
and for thisFoo object
to have its delegate property set:
Foo *obj = [[Foo alloc] init];
[obj setDelegate:self];
Now, your class is prepared to receive messages from Foo objects
that have their delegates set correctly.