iOS Extension Category Protrol 例子理解

直接上代码

先读懂代码才能更好的理解含义。

Demo地址：https://github.com/RainManGO/ExtensionCateGoryProtrolDemo

目录：

Person类没有暴漏任何方法：

////  Person.h//  ExtensionCateGoryProtrolDemo////  Created by apple on 2017/12/14.//  Copyright © 2017年 ZY. All rights reserved.//#import <Foundation/Foundation.h>#import "Study.h"@interface Person : NSObject<Study>@end

////  Person.m//  ExtensionCateGoryProtrolDemo////  Created by apple on 2017/12/14.//  Copyright © 2017年 ZY. All rights reserved.//#import "Person.h"#import <objc/runtime.h>//这也是类扩展@interface Person ()@property(nonatomic,assign) int age;@end@implementation Person-(void)logAge{    self.age = 18;    NSLog(@"%d",self.age);}-(void)Eat{    NSLog(@"Eat");}-(void)Study{    NSLog(@"Study");}-(void)setFriendName:(NSString *)name{    objc_setAssociatedObject(self, @"friendName", name,OBJC_ASSOCIATION_COPY_NONATOMIC);}-(NSString *)friendName{    return objc_getAssociatedObject(self, @"friendName");}@end

Category用runtime方法实现了可以设置属性：

////  Person+Run.h//  ExtensionCateGoryProtrolDemo////  Created by apple on 2017/12/14.//  Copyright © 2017年 ZY. All rights reserved.//#import "Person.h"@interface Person (Run)@property(nonatomic,strong)NSString * name;-(void)Run;@end

////  Person+Run.m//  ExtensionCateGoryProtrolDemo////  Created by apple on 2017/12/14.//  Copyright © 2017年 ZY. All rights reserved.//#import "Person+Run.h"#import <objc/runtime.h>@implementation Person (Run)-(void)Run{    NSLog(@"Run");}-(void)setName:(NSString *)name{    objc_setAssociatedObject(self, @"name", name,OBJC_ASSOCIATION_COPY_NONATOMIC);}-(NSString *)name{    return objc_getAssociatedObject(self, @"name");}@end

单独的Extension文件相当于一个需要自己实现的Category(本例子已经在Person类实现)：

////  Person+Eat.h//  ExtensionCateGoryProtrolDemo////  Created by apple on 2017/12/14.//  Copyright © 2017年 ZY. All rights reserved.//#import "Person.h"@interface Person ()@property(nonatomic,copy)NSString * friendName;-(void)logAge;-(void)Eat;@end

Protocol和Extension一样需要别人实现，我理解的区别是Extension必须要你扩展的类实现，而protocol谁遵守协议谁实现：

////  Study.h//  ExtensionCateGoryProtrolDemo////  Created by apple on 2017/12/14.//  Copyright © 2017年 ZY. All rights reserved.//#import <Foundation/Foundation.h>@protocol Study <NSObject>-(void)Study;@end

调用类：

////  ViewController.m//  ExtensionCateGoryProtrolDemo////  Created by apple on 2017/12/14.//  Copyright © 2017年 ZY. All rights reserved.//#import "ViewController.h"#import "Person+Run.h"#import "Extension/Person+Eat.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];        Person  *  Mryang  = [Person new];    Mryang.name =  @"Mryang";    Mryang.friendName =@"MrsLu";    NSLog(@"%@",Mryang.name);    NSLog(@"%@",Mryang.friendName);        [Mryang logAge];    [Mryang Run];    [Mryang Eat];    [Mryang Study];}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];}@end

打印结果可想而知。见demo