Objective-C Delegate

gistfile1.m

//
// AViewController.h
//
@protocol AViewControllerDelegate;

@interface AViewController : UIViewController <AViewControllerDelegate> 
{
    id <AViewControllerDelegate> delegate;
}
@property (nonatomic, retain) id <AViewControllerDelegate> delegate;
@end

@protocol AViewControllerDelegate <NSObject>
@optional
//- (void)delegateMethod;
@end 


//
// AViewController.m
//
@implementation AViewController
@synthesize delegate;
- (void)aMethod 
{
    if (delegate && [delegate respondsToSelector:@selector(delegateMethod)]) 
    {
        [delegate delegateMethod];
    }
}
@end


//
// BViewController.h
//
#import "AViewController.h"
@interface BViewController : UIViewController <AViewControllerDelegate> { }
@end

//
// BViewController.m
//
@implementation BViewController
- (void)delegateMethod 
{
    // process
}
@end