protocol協議的創建

首先創建一個協議的頭文件

@protocol BiteDelegate <NSObject>
@optional
- (void)biteSomeone:(id)someone;

@end

person.h中聲明以下代碼

#import "Dog.h"
#import "BiteDelegate.h"

#import <Foundation/Foundation.h>

typedef int * Pointer;

@interface Person : NSObject
@property (nonatomic, strong) Dog *dog;
@property (nonatomic, strong) id something;
@property (nonatomic, strong) id<BiteDelegate> delegate;

- (void)print;
@end

person.h

#import "Person.h"

@implementation Person
- (void)print
{
    int a = 10;
    Pointer pa = &a;
    *pa = 30;
    NSLog(@"%d", a);
}
@end

Dog.h

#import <Foundation/Foundation.h>

#import "BiteDelegate.h"

@interface Dog : NSObject <BiteDelegate>

@end

Dog.m

#import "Dog.h"

@implementation Dog
- (void)biteSomeone:(id)someone
{
    NSLog(@"%@", someone);
}
@end