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！！！