数据持久化之NSKeyedArchiver

         基本的数据类型如NSString、NSDictionary、NSArray、NSData、NSNumber等可以用属性列表的方法持久化到.plist 文件中，但如果是一些自定义的类的话，属性列表的方法就不管用了。archiver 方法可以做到。

编码如下：

     首先新建一个person类，定义它的三个属性，如下：

////  person.h//  数据持久化之archiver////  Created by Rio.King on 13-9-22.//  Copyright (c) 2013年 Rio.King. All rights reserved.//#import <UIKit/UIKit.h>@interface person : UIView<NSCoding>@property(nonatomic, assign) int age;@property(nonatomic, copy)NSString *name;@property(nonatomic, assign)float height;@end

////  person.m//  数据持久化之archiver////  Created by Rio.King on 13-9-22.//  Copyright (c) 2013年 Rio.King. All rights reserved.//#import "person.h"@implementation person#pragma mark 写入文件-(void)encodeWithCoder:(NSCoder *)encoder{    [super encodeWithCoder:encoder];//不要忘了这个    [encoder encodeInt:self.age forKey:@"age"];    [encoder encodeObject:self.name forKey:@"name"];    [encoder encodeFloat:self.height forKey:@"height"];}#pragma mark 从文件中读取-(id)initWithCoder:(NSCoder *)decoder{    self = [super initWithCoder:decoder];//不要忘了这个    self.age = [decoder decodeIntForKey:@"age"];    self.name = [decoder decodeObjectForKey:@"name"];    self.height = [decoder decodeFloatForKey:@"height"];            return self;}-(NSString *)description{    return [NSString stringWithFormat:@"name = %@, age = %d, height = %f",self.name,self.age,self.height];}//释放资源-(void)dealloc{    [super dealloc];    [_name release];}@end

然后再ViewController.m文件中写如下代码：

////  ViewController.m//  数据持久化之archiver////  Created by Rio.King on 13-9-22.//  Copyright (c) 2013年 Rio.King. All rights reserved.//#import "ViewController.h"#import "person.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad{    [super viewDidLoad];    [self createPerson];[self readPerson];}//创建-(void)createPerson{        person *p = [[[person alloc] init] autorelease];    p.age = 20;    p.name = @"Rio";    p.height =1.75f;        //获得Document的路径    NSString *documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];    NSString *path = [documents stringByAppendingPathComponent:@"person.archiver"];//拓展名可以自己随便取        [NSKeyedArchiver archiveRootObject:p toFile:path];    }//读取-(void)readPerson{    NSString *documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];    NSString *path = [documents stringByAppendingPathComponent:@"person.archiver"];    person *person1 = [NSKeyedUnarchiver unarchiveObjectWithFile:path];    NSLog(@"%@",person1);}@end

，，在写ViewController.m文件代码的时候，必须在头文件中遵循NSCoding协议。

#import <UIKit/UIKit.h>@interface ViewController : UIViewController<NSCoding>@end

运行结果如下:

2013-09-22 13:31:39.509 数据持久化之archiver[1080:c07] name = Rio, age = 20, height = 1.750000

注意事项：