OC面向对象-多态

时间：2015-09-25 13:04:32 阅读：214 评论：0 收藏：0 [点我收藏+]

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from : http://www.cnblogs.com/wendingding/p/3705428.html

其实多态说白了就是：定义类型和实际类型，一般是基于接口的形式实现的。

例子：

Animal类

//
//  Animal.h
//  WDDDuotaiTest
//
//  Created by LiuChanghong on 15/9/24.
//  Copyright © 2015年 LiuChanghong. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Animal : NSObject

-(void)eat;

@end

Animal.h

//
//  Animal.m
//  WDDDuotaiTest
//
//  Created by LiuChanghong on 15/9/24.
//  Copyright © 2015年 LiuChanghong. All rights reserved.
//

#import "Animal.h"

@implementation Animal

-(void)eat{
    NSLog(@"动物吃东西");
}

@end

Animal.m

Dog类

//
//  Dog.h
//  WDDDuotaiTest
//
//  Created by LiuChanghong on 15/9/24.
//  Copyright © 2015年 LiuChanghong. All rights reserved.
//

#import "Animal.h"

@interface Dog : Animal

//重写eat方法
-(void)eat;

@end

Dog.h

//
//  Dog.m
//  WDDDuotaiTest
//
//  Created by LiuChanghong on 15/9/24.
//  Copyright © 2015年 LiuChanghong. All rights reserved.
//

#import "Dog.h"

@implementation Dog

-(void)eat{
    NSLog(@"狗吃东西");
}

@end

Dog.m

Cat类

//
//  Cat.h
//  WDDDuotaiTest
//
//  Created by LiuChanghong on 15/9/24.
//  Copyright © 2015年 LiuChanghong. All rights reserved.
//

#import "Animal.h"

@interface Cat : Animal

//重写eat方法
-(void)eat;

@end

cat.h

//
//  Cat.m
//  WDDDuotaiTest
//
//  Created by LiuChanghong on 15/9/24.
//  Copyright © 2015年 LiuChanghong. All rights reserved.
//

#import "Cat.h"

@implementation Cat

-(void)eat{
    NSLog(@"猫吃东西");
}

@end

Cat.m

测试程序

//
//  main.m
//  WDDDuotaiTest
//
//  Created by LiuChanghong on 15/9/24.
//  Copyright © 2015年 LiuChanghong. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "Animal.h"
#import "Dog.h"
#import "Cat.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
        Animal *animal = [Animal new];
        [animal eat];
        
        Dog *doggg = [Dog new];
        [doggg eat];
        
        Cat *cattt = [Cat new];
        [cattt eat];
        
        //多态 父类指针指向子类对象
        Animal *dog = [Dog new];
        //动态监测 调用方法时会检测对象的真实类型
        [dog eat];
    
        
        Animal *cat = [Cat new];
        [cat eat];
        
        NSObject *object = [Animal new];
//        [object eat];//没有eat方法
        
        Animal *object_Animal = (Animal*)object;//使用强制转换，这里object和object_Animal指向的是同一个Animal对象
        [object_Animal eat];
        
    }
    return 0;
}