NSCopying简析

用到NSCopying的时候并不多,但还是有必要知道最基本的用途,比方说数组的拷贝操作,需要注意的是,数组的拷贝操作并不是执行了 copy 方法,而是需要执行 initWithArray:copyItems: ,这点需要注意.

源码:

//
//  Model.h
//  NSCopy
//
//  Created by YouXianMing on 15/5/2.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Model : NSObject <NSCopying/* 继承NSCopying协议 */>

// 对象类型
@property (nonatomic, strong) NSString  *name;
@property (nonatomic, strong) NSNumber  *age;

// 基本数据类型
@property (nonatomic, assign) BOOL       isMale;

@end

//
//  Model.m
//  NSCopy
//
//  Created by YouXianMing on 15/5/2.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import "Model.h"

@implementation Model

- (id)copyWithZone:(NSZone *)zone {

    // 获取拷贝内容
    Model *copy = [[[self class] allocWithZone:zone] init];

    // 基本属性的类型本身实现了copy协议
    copy.name = [_name copy];
    copy.age  = [_age  copy];

    // 常规类型属性仅仅需要赋值即可
    copy.isMale = _isMale;

    return copy;
}

@end

控制器源码:

//
//  ViewController.m
//  NSCopy
//
//  Created by YouXianMing on 15/5/2.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import "ViewController.h"
#import "Model.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // 对象1
    Model *modelOne = [Model new];
    modelOne.name   = @"YouXianMing";
    modelOne.age    = @(28);

    // 对象1的复制
    Model *modelCopy = [modelOne copy];

    // 打印信息
    NSLog(@"%@ %@", modelOne, modelOne.name);
    NSLog(@"%@ %@", modelCopy, modelCopy.name);

    // 数组
    NSArray *array = @[modelOne, modelCopy];

    // 数组的复制
    NSArray *arrayCopy = [[NSArray alloc] initWithArray:array copyItems:YES];

    // 打印信息
    NSLog(@"%@", array);
    NSLog(@"%@", arrayCopy);

}

@end

简单的分析: