IOS学习笔记十(多态)

1、多态

相同类型调用同一个方法呈现多种不同的行为特征就是多态

当子类对象直接赋值给父类指针变量，父类 *p = [子类 new];，运行类型是子类，编译类型是父类，所以p不能调用子类单独实现的方法，如果子类重写了父类方法，p调用的方法会是子类重写的方法


isKindOfClass:clazz

判断该对象是否为clazz或者其子类的实例


2、测试demo

KFBase.h

    #import <Foundation/Foundation.h>
     
    #ifndef KFBase_h
    #define KFBase_h
     
    @interface KFBase : NSObject
    -(void)base;
    -(void)test;
    @end
     
    #endif /* KFBase_h */


KFBase.m

    #import <Foundation/Foundation.h>
    #import "KFBase.h"
     
    @implementation KFBase
    -(void)base
    {
        NSLog(@"parent base method");
    }
    -(void)test
    {
        NSLog(@"parent test method");
    }
    @end


SubClass.h

    #import "KFBase.h"
     
    #ifndef Subclass_h
    #define Subclass_h
    @interface Subclass : KFBase
    -(void)sub;
    -(void)test;
    @end
     
    #endif /* Subclass_h */


SubClass.m

    #import <Foundation/Foundation.h>
    #import "Subclass.h"
     
    @implementation Subclass
    -(void)sub
    {
         NSLog(@"child sub method");
    }
    -(void)test
    {
         NSLog(@"chile test method");
    }
    @end


main.m

    #import "KFBase.h"
    #import "Subclass.h"
     
    int main(int argc, char * argv[]) {
        @autoreleasepool {
            KFBase *base = [KFBase new];
            [base base];
            [base test];
            Subclass *sub = [Subclass new];
            [sub base];
            [sub test];
            [sub sub];
            
            KFBase *seBase = [Subclass new];
            [seBase base];
            [seBase test];
            //下面运行会编译出错
    //        [seBase sub];
            id dy = seBase;
            [dy sub];
            NSLog(@"sub是KFBase的子类吗？%d",[sub isKindOfClass:[KFBase class]]);
        }
    }


3、运行结果

    parent base method
    parent test method
    parent base method
    chile test method
    child sub method
    parent base method
    chile test method
    child sub method
    sub是KFBase的子类吗？1



 

作者：chen.yu
深信服三年半工作经验，目前就职游戏厂商，希望能和大家交流和学习,
微信公众号：编程入门到秃头 或扫描下面二维码
零基础入门进阶人工智能(链接)