Objective-C代理

1.代理初识 

假设BOSS需要买电脑   让worker去买  

这时boss需要一个代理即为worker 去买电脑

BOSS创建一个协议  协议中的方法为买电脑

BOSS有一个属性 属性的类为遵守协议的类

BOSS有一个成员方法   方法的实现为 代理去买电脑 

worker类需要遵守协议  实现协议方法 买电脑

代码实现如下 

#import <Foundation/Foundation.h>
#import "Boss.h"
#import "Worker.h"

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

        Boss * boss = [[Boss alloc] init];
        Worker * worker = [[Worker alloc] init];
        [boss setDelegate:worker];
        [boss delegateBuyMacbook];
                
    }
    return 0;
}

#import <Foundation/Foundation.h>

//创建协议
@protocol BossDelegate <NSObject>

- (void)buyMacbook;

@end


@interface Boss : NSObject
//有一个遵守协议的代理
@property (nonatomic,weak) id<BossDelegate> delegate;
//方法调用代理去买电脑
- (void)delegateBuyMacbook;
@end

#import "Boss.h"

@implementation Boss
- (void)delegateBuyMacbook {
    NSLog(@"老板开始找人买电脑");
    [_delegate buyMacbook];
}
@end

#import <Foundation/Foundation.h>
#import "Boss.h"
@interface Worker : NSObject<BossDelegate>

@end

#import "Worker.h"

@implementation Worker
- (void)buyMacbook {
    NSLog(@"买了60台Macbook Pro 15 高配");
}
@end

2.代理回调

/*

 //当我们需要完成某个功能模块，但不知道使用功能模块的是哪个对象，通过协议，可以规定接收数据的对象通过哪个方法获得数据。调用该方法的过程称为【回调】

*/

#import <Foundation/Foundation.h>
#import "LRCManager.h"
int main(int argc, const char * argv[]) {
    @autoreleasepool {
//        Download *d = [Download new];
        LRCManager * lrcManager = [[LRCManager alloc] init];
//        lrcManager.download = d;
//        d = nil;
//        
//        Download __weak *  download = [Download new];
//        
//        NSLog(@"%@",lrcManager.download);
        [lrcManager run];
    }
    return 0;
}

#import <Foundation/Foundation.h>
#import "Download.h"
/*
 //当我们需要完成某个功能模块，但不知道使用功能模块的是哪个对象，通过协议，可以规定接收数据的对象通过哪个方法获得数据。调用该方法的过程称为【回调】
*/
@interface LRCManager : NSObject<DownloadDelegate>
@property (nonatomic,weak) Download * download;
@property (nonatomic,strong) NSString * lrcContent;
- (void)run;
+ (void)test;
@end

#import "LRCManager.h"

@implementation LRCManager

+ (void)test {
    LRCManager * lrcManager = [[LRCManager alloc] init];
    [lrcManager run];
}

- (void)run {
    Download * download = [[Download alloc] init];
    download.delegate = self;
    [download downloadWithURLPath:@"www.baidu.com"];    
}

- (void)downloadFinished:(NSString *)str {
    NSLog(@"%@",str);
}

- (void)dealloc {
    NSLog(@"lrcManager dealloc");
}
@end

#import <Foundation/Foundation.h>

@protocol DownloadDelegate <NSObject>

- (void)downloadFinished:(NSString *)str;

@end

@interface Download : NSObject
@property (nonatomic,weak) id<DownloadDelegate> delegate;
- (void)downloadWithURLPath:(NSString *)path;
@end

#import "Download.h"

@implementation Download
- (void)downloadWithURLPath:(NSString *)path {
    int i = 0;
    while (i++ < 5) {
        printf("下载中
");
        sleep(1);
    }
    NSString * lrcStr= @"我是下载到的字符串";
    [_delegate downloadFinished:lrcStr];
}

- (void)dealloc {
    NSLog(@"download dealloc");
}
@end

3.双向代理  

Boss需要个代理去工作

Worker需要代理发工资