先来定义一个Human父类
定义部分：
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | // // Human.h // OOP // // Created by jimmy.yang on 11-2-9. // Copyright 2011 __MyCompanyName__. All rights reserved. // #import <Foundation/Foundation.h> @interface Human : NSObject { BOOL sex; } +( void ) toString; -( void ) showSex; @end |
注：+(void)前的加号，就表示这一个是类方法(static 方法)，而-(void)表示这是一个实例方法
实现部分：
注意：下面的 -(id) init 即为构造函数。对应的，还有一个-(void)dealloc方法用来释放资源（类似于析构函数或c#中的dispose()方法）-注：dealloc方法以后在内存管理中详细学习，这里先不管它。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | // // Human.m // OOP // // Created by jimmy.yang on 11-2-9. // Copyright 2011 __MyCompanyName__. All rights reserved. // #import "Human.h" @implementation Human //构造函数 -( id ) init { NSLog (@ "init() in Human is called" ); sex = TRUE; return ( self ); } //static类方法 + ( void )toString { NSLog (@ "this is a class method of Human" ); } //实例方法 - ( void )showSex { NSLog (@ "my sex is %@" ,sex?@ "MALE" :@ "FEMALE" ); } @end |
再来定义一个Woman子类
定义部分：
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | // // Woman.h // OOP // // Created by jimmy.yang on 11-2-9. // Copyright 2011 __MyCompanyName__. All rights reserved. // #import <Foundation/Foundation.h> #import "Human.h" @interface Woman : Human { BOOL married; } -( void ) canCook:( NSString *) foodName; -( void ) setMarried:( BOOL )m; -( BOOL ) Married; @end |
实现部分：
注意下面的：setMarried 与 Married 就是obj-C中属性的标准写法(当然以后还能看到其它简化的写法)
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | // // Woman.m // OOP // // Created by jimmy.yang on 11-2-9. // Copyright 2011 __MyCompanyName__. All rights reserved. // #import "Woman.h" @implementation Woman //Woman类的构造函数 -( id ) init{ NSLog (@ "init() in Woman is called!" ); if ( self ==[ super init]){ sex = FALSE; married = FALSE; } return ( self ); } //overwrite父类中的toString() +( void )toString { NSLog (@ "This is Woman's ToString()" ); } //Woman能做饭 -( void )canCook:( NSString *) foodName { NSLog (@ "I can cook %@" ,foodName); } //属性的setter -( void ) setMarried:( BOOL )m { married = m; } //属性的getter -( BOOL ) Married { return married; } @end |
main方法中的调用：
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 | #import <Foundation/Foundation.h> #import "Human.h" #import "Woman.h" int main ( int argc, const char * argv[]) { NSAutoreleasePool * pool = [[ NSAutoreleasePool alloc] init]; // insert code here... NSLog (@ "Hello, World!" ); //调用类的“静态”方法 [Human toString]; NSLog (@ "----------------" ); //创造一个Human的实例 Human *man = [Human new ]; //调用man的showSex方法 [man showSex]; NSLog (@ "----------------" ); //定义一个Woman子类的实例 Woman *wife = [Woman new ]; [wife canCook:@ "Rice" ]; //调用继承自父类的方法 [wife showSex]; //设置属性 [wife setMarried:TRUE]; //读取属性值 NSLog (@ "wife's married = %@" ,wife.Married== NO ?@ "FALSE" :@ "TRUE" ); NSLog (@ "----------------" ); //调用overwrite后的toString方法 [Woman toString]; //Factory模式中常用的手法，在这里依然适用(只不过编译时会有警告 'Human' may not respond to '-canCook:') Human *wife2 = [Woman new ]; [wife2 canCook:@ "soap" ]; NSLog (@ "----------------" ); [pool drain]; return 0; } |
运行结果：
2011-02-09 17:01:02.016 OOP[1725:a0f] Hello, World!
2011-02-09 17:01:02.053 OOP[1725:a0f] this is a class method of Human2011-02-09 17:01:02.062 OOP[1725:a0f] ----------------2011-02-09 17:01:02.075 OOP[1725:a0f] init() in Human is called2011-02-09 17:01:02.091 OOP[1725:a0f] my sex is MALE2011-02-09 17:01:02.094 OOP[1725:a0f] ----------------2011-02-09 17:01:02.099 OOP[1725:a0f] init() in Woman is called!2011-02-09 17:01:02.104 OOP[1725:a0f] init() in Human is called2011-02-09 17:01:02.105 OOP[1725:a0f] I can cook Rice2011-02-09 17:01:02.108 OOP[1725:a0f] my sex is FEMALE2011-02-09 17:01:02.109 OOP[1725:a0f] wife's married = TRUE2011-02-09 17:01:02.111 OOP[1725:a0f] ----------------2011-02-09 17:01:02.116 OOP[1725:a0f] This is Woman's ToString()2011-02-09 17:01:02.120 OOP[1725:a0f] init() in Woman is called!2011-02-09 17:01:02.121 OOP[1725:a0f] init() in Human is called2011-02-09 17:01:02.123 OOP[1725:a0f] I can cook soap2011-02-09 17:01:02.125 OOP[1725:a0f] ---------------- 作者： 出处： 本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
原文：http://www.cnblogs.com/yjmyzz/archive/2011/02/09/1950305.html