最精简 代理代码

@protocol XieYi <NSObject>

//1, 定义

- (void)star;

@end

@interface Shixian : NSObject <XieYi>

@end

@implementation Shixian

//4， 实现

- (void)star

{    

    NSLog(@" 这是 协议方法的 实现");

}

@end

@interface ShiYong : NSObject

//2, 设置属性

@property (nonatomic,assign) id <XieYi> delegate;

- (void)crying;

@end

@implementation ShiYong

//3 发起使用

- (void)crying

{   //3， 使用

    [self.delegate star];

}

- (void)dealloc

{

    self.delegate = nil;

    [super dealloc];

}

@end

 

int main(int argc, const char * argv[]){

    @autoreleasepool {

        Shixian *shixian = [Shixian new];

        ShiYong *shiyong = [ShiYong new];

        //5,设置代理

        shiyong.delegate = shixian;

        //6，

        [shiyong crying];

    }

    return 0;

}