objective-C 的OOP

 先来定义一个Human父类

定义部分

//

//  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。

//

//  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：

//

//  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)

//

//  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：

#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 Human
2011-02-09 17:01:02.062 OOP[1725:a0f] ----------------
2011-02-09 17:01:02.075 OOP[1725:a0f] init() in Human is called
2011-02-09 17:01:02.091 OOP[1725:a0f] my sex is MALE
2011-02-09 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 called
2011-02-09 17:01:02.105 OOP[1725:a0f] I can cook Rice
2011-02-09 17:01:02.108 OOP[1725:a0f] my sex is FEMALE
2011-02-09 17:01:02.109 OOP[1725:a0f] wife's married = TRUE
2011-02-09 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 called
2011-02-09 17:01:02.123 OOP[1725:a0f] I can cook soap
2011-02-09 17:01:02.125 OOP[1725:a0f] ----------------