NSKeyedArchiver的基础用法

 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。

 

ep1 代码如下：

 

NSString *str = @"abc";
NSString *astr = @"efg";
NSArray *Array = [NSArray arrayWithObjects:str, astr, nil];

//保存数据
NSString *Path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; NSString *filename = [Path stringByAppendingPathComponent:@"test.plist"];
[NSKeyedArchiver archiveRootObject:Array toFile:filename];

str = @"a";
astr = @"";

//加载数据
NSArray *arr = [NSKeyedUnarchiver unarchiveObjectWithFile: filename];
str = [arr objectAtIndex:0];
astr =  [arr objectAtIndex:1];

NSLog(@"str:%@",str);
NSLog(@"astr:%@",astr);

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

 

 

单个对象归档:

 

NSArray *array = @[@"111", @"aaa", @333, @"asdf3111"];
NSString *homePath = NSHomeDirectory();
NSString *filePath = [homePath stringByAppendingPathComponent:@"test.txt"];
BOOL result = [NSKeyedArchiver archiveRootObject:array toFile:filePath];
if (result) {
    NSLog(@"archiver success");
}


//解归档
NSString *homePath = NSHomeDirectory();
NSString *filePath = [homePath stringByAppendingPathComponent:@"test.txt"];

NSArray *array = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
NSLog(@"%@", array);

 

多个对象归档:

 

<span style="white-space:pre">  </span>//NSMutableData NSKeyedArchiver配合 归档多个对象
        NSString *homePath = NSHomeDirectory();
        NSString *filePath = [homePath stringByAppendingPathComponent:@"multiple.data"];

        NSMutableData *mutableData = [NSMutableData data];

        //使用mutableData创建归档对象
        NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:mutableData];

        NSArray *array = @[@"ary1", @"ary2"];

        [archiver encodeInt:20 forKey:@"intKey"];
        [archiver encodeObject:array forKey:@"arrayKey"];
        [archiver encodeObject:@"NSString value" forKey:@"stringkey"];
        [archiver finishEncoding];
        [archiver release];

        BOOL result = [mutableData writeToFile:filePath atomically:YES];
        if (result) {
            NSLog(@"写入成功");
        }


        //NSData 配合NSKeyedUnarchiver解归档多个对象
        NSString *homePath = NSHomeDirectory();
        NSString *filePath = [homePath stringByAppendingPathComponent:@"multiple.data"];

        NSData *data = [NSData dataWithContentsOfFile:filePath];
        NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];

        int intVal = [unarchiver decodeIntForKey:@"intKey"];
        NSArray *aryVal = [unarchiver decodeObjectForKey:@"arrayKey"];
        NSString *strVal = [unarchiver decodeObjectForKey:@"stringkey"];

        NSLog(@"intVal %d", intVal);
        NSLog(@"aryVal %@", aryVal);
        NSLog(@"strVal %@", strVal);

        [unarchiver release];