IOS开发之kvc简单介绍

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1.概念：
kvc也就是key value coding 就是键值编码。我们利用kvc可以给对象初始化，也可以去某个对象的值赋给另一个对象。
2.简单例子（利用kvc初始化对象，取某个对象的值付给另一对象）

person类：

#import <Foundation/Foundation.h>#import "Book.h"@interface Person : NSObject@property (nonatomic,copy) NSString* name;@property (nonatomic,assign) int age;@property (nonatomic,strong) Book *book;@end

Book类：

#import <Foundation/Foundation.h>@interface Book : NSObject@property (nonatomic,copy) NSString *bookName;@end

////  main.m//  KVCDemo_01////  Created by QiZhang on 8/5/15.//  Copyright (c) 2015 QiZhang. All rights reserved.//#import <Foundation/Foundation.h>#import "Person.h"int main(int argc, const char * argv[]) {    // 1.利用kvc可以为对象初始化    Person *p1 = [[Person alloc] init];    [p1 setValue:@"SanZhang" forKeyPath:@"name"];    [p1 setValue:@"23" forKeyPath:@"age"];    Book *b1 = [[Book alloc] init];    b1.bookName = @"Iphone";    p1.book = b1;    Person *p2 = [[Person alloc] init];    [p2 setValue:@"SiLi" forKeyPath:@"name"];    [p2 setValue:@"20" forKeyPath:@"age"];    Book *b2 = [[Book alloc] init];    [b2 setValue:@"IOS" forKeyPath:@"bookName"];    [p2 setValue:b2 forKeyPath:@"book"];    NSLog(@"%@-----%@",p1,[p2 valueForKey:@"name"]);    NSLog(@"*******************");    NSArray *persons = @[p1,p2];    NSMutableArray *arrayM = [NSMutableArray array];    [arrayM addObject:[persons valueForKeyPath:@"book.bookName"]]; //利用kvc可以很方便的去取值    NSLog(@"%@",arrayM);    return 0;}

运行结果：

2015-08-05 19:18:42.154 KVCDemo_01[13536:567138] <Person:0x100211e80>,{name:SanZhang,age:23}-----SiLi2015-08-05 19:18:42.155 KVCDemo_01[13536:567138] *******************2015-08-05 19:18:42.155 KVCDemo_01[13536:567138] (        (        Iphone,        IOS    ))

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