iOS 序列化与反序列化

研究了一下 NSKeyedArchiver 和 NSKeyedUnarchiver ，其中遇到了一个麻烦的问题，研究许久才找到问题，在此留念吧！

概述：

  1. 序列化是iOS数据持久化中的一种方式，其他的方式包括plist 文件， 数据库， NSUserDefaults 等，而序列化相对于其他几种方式的的优点是它可以持久化对象，或者说类。

   2. 如果对象是NSString, NSDictionary , NSArray , NSData, NSNumber 等类型，可以直接使用NSKeyedArchiver 进行归档和NSKeyedUnarchiver 进行恢复；

3. 不是所有的对象都可以使用这种方法，只有遵守了NSCoding 协议的对象才可以，NScoding 的协议有两个，分别是：

encodeWithCoder: 每次归档对象时，都会调相应的这个方法，在这个方法里指定如果归档对象中的每个实力变量，可以使用encodeObjec:forKey: 方法归档其中的实例变量；

initWithCoder: 每次从文件中恢复对象时，都会调用这个方法，在这个方法中指定如何解码文件中的数据为对象的实例变量，可以使用decodeObject:forKey: 方法解码实例变量；

下面是具体的测试代码：

//viewController.m

#import "ViewController.h"#import "ArchiverDataModel.h"@interface ViewController ()<NSKeyedArchiverDelegate,NSKeyedUnarchiverDelegate>{    NSMutableArray *_array;}@property (retain, nonatomic) ArchiverDataModel *dataModel;@end@implementation ViewController@synthesize dataModel;- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        // Custom initialization    }    return self;}- (void)addButtonFrame:(CGRect)frame title:(NSString *)title selecter:(SEL)selecter{    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];    button.frame = frame;    [button setTitle:title forState:UIControlStateNormal];    [button addTarget:self action:selecter forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:button];}- (void)viewDidLoad{    [super viewDidLoad];// Do any additional setup after loading the view.    self.view.backgroundColor = [UIColor grayColor];        [self addButtonFrame:CGRectMake(100, 100, 120, 40) title:@"归档" selecter:@selector(archiver:)];    [self addButtonFrame:CGRectMake(100, 200, 120, 40) title:@"解档" selecter:@selector(unArchiver:)];        self.dataModel.name = @"123";    self.dataModel.age = 123;        _array = [[NSMutableArray alloc]initWithArray:@[@"1",@"2",@"3"]];            }- (void)archiver:(UIButton *)button{        /*     普通变量的序列化         NSString *filePath = @"/Users/tongkun/Desktop/archiver.archiv";    NSMutableData *data = [[NSMutableData alloc]init];    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];    [archiver encodeObject:self.dataModel forKey:@"dataModel"];    [archiver encodeObject:_array forKey:@"array"];    [archiver encodeInt:10 forKey:@"int"];    [archiver finishEncoding];    BOOL ret = [data writeToFile:filePath atomically:YES];    NSLog(@"ret: %d",ret);     */        NSString *filePath = @"/Users/tongkun/Desktop/archiver.archiv"; //扩展名可以随便取    NSMutableData *data = [[NSMutableData alloc]init];    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];    archiver.delegate = self;    ArchiverDataModel *model = [[ArchiverDataModel alloc]init];    model.name = @"name";    model.age = 1;    [archiver encodeObject:model forKey:@"dataModel"];    /*      此处我尝试用ArchiverDataModel 作为self的属性进行归档，归档也能成功，但是并不调用对象类中的encodeWithCoder：方法，但是文件恢复（解码）不出来，也并没有调用对象类中的initWithCoder： 方法，暂时没找到解决办法，所以只能创建一个独立的ArchiverDataModel变量进行测试了     */    [archiver finishEncoding];    BOOL ret = [data writeToFile:filePath atomically:YES];    NSLog(@"ret: %d",ret);    }- (void)unArchiver:(UIButton *)button{    /*     普通的归档的恢复         NSString *filePath = @"Users/tongkun/Desktop/archiver.archiv";    NSData *data = [NSData dataWithContentsOfFile:filePath];    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc]initForReadingWithData:data];    NSArray *array = [unarchiver decodeObjectForKey:@"array"];    int i = (int)[unarchiver decodeObjectForKey:@"int"];    NSLog(@"array: %@, i: %d",array, i);     */        NSString *filePath = @"/Users/tongkun/Desktop/archiver.archiv";    NSData *data = [NSData dataWithContentsOfFile:filePath];    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc]initForReadingWithData:data];    unarchiver.delegate = self;    ArchiverDataModel *model = [unarchiver decodeObjectForKey:@"dataModel"];    [unarchiver finishDecoding];    NSLog(@"model.name : %@, model.age : %ld",model.name, model.age);    }#pragma -mark #pragma -mark NSKeyedArchiver / NSKeyedUnarchiver Delegate- (void)archiverDidFinish:(NSKeyedArchiver *)archiver{    NSLog(@"archiverDidFinish");}- (void)unarchiverDidFinish:(NSKeyedUnarchiver *)unarchiver{    NSLog(@"unarchiverDidFinish");}- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

//对象中的NSCoding 协议的实现

// ArchiverDataModel.h

#import "ArchiverDataModel.h"@implementation ArchiverDataModel@synthesize name;@synthesize age;- (void)encodeWithCoder:(NSCoder *)aCoder{    [super encodeWithCoder:aCoder]; //如果父类也实现NSCoding 协议则应该写这句    [aCoder encodeObject:name forKey:@"name"];    [aCoder encodeInteger:age forKey:@"age"];}//对属性解码，解归档调用- (id)initWithCoder:(NSCoder *)aDecoder{    self = [super init];    if (self) {        self.name = [aDecoder decodeObjectForKey:@"name"];        self.age = [aDecoder decodeIntegerForKey:@"age"];    }    return self;}@end

暂时就先测试这么多，以后用到得时候在继续完善！！！