归档反归档 - 本地沙盒存储复杂对象

Posted 2020-06-29 Kriskee

　　NSString，NSNumber，NSArray，NSDictionary等简单对象可以方便的存储在本地沙盒文件中，而复杂的对象，诸如属性、方法较多的类对象，就需要使用归档反归档方法（序列化与反序列化），以NSData方式进行存储。

　　归档反归档，主要的操作顺序是：编码(enCoding) -> 归档(archiver) -> 解码(deCoding) -> 反归档(unarchiver)

　　1.编码与解码的方法，需要在类的声明文件中接受<NSCoding>协议，在实现文件.m中完成协议方法:　　

 1 /*
 2  * Model.h 接受NSCoding协议 
 3  */
 4 
 5 #import <Foundation/Foundation.h>
 6 #import <UIKit/UIKit.h>
 7 
 8 @interface Model : NSObject<NSCoding>
 9 @property(nonatomic,strong)NSString *name;
10 @property(nonatomic,assign)NSInteger num;
11 
12 - (instancetype)initWithName:(NSString *)name num:(NSInteger)num;
13 @end

 1 /*
 2  * Model.m 实现编码与解码的协议方法 
 3  */
 4 
 5 #import "Model.h"
 6 
 7 @implementation Model
 8 - (instancetype)initWithName:(NSString *)name num:(NSInteger)num{
 9     self = [super init];
10     if(self){
11         self.name = name;
12         self.num = num;
13     }
14     return self;
15 }
16 
17 // 编码
18 - (void)encodeWithCoder:(NSCoder *)aCoder{
19     [aCoder encodeObject:self.name forKey:@"name"];
20     [aCoder encodeObject:@(self.num) forKey:@"num"];
21 }
22 
23 // 解码
24 - (instancetype)initWithCoder:(NSCoder *)aDecoder{
25     self = [super init];
26     if(self){
27         self.name = [aDecoder decodeObjectForKey:@"name"];
28         self.num = [[aDecoder decodeObjectForKey:@"num"] integerValue];
29     }
30     return self;
31 }
32 
33 @end

　　2.归档 - 保存复杂对象；反归档 - 获取对象

 1 #import "ViewController.h"
 2 #import "Model.h"
 3 
 4 @interface ViewController ()
 5 @property (weak, nonatomic) IBOutlet UIImageView *image;
 6 @property (weak, nonatomic) IBOutlet UITextField *nameText;
 7 @property (nonatomic,strong)NSString *path;
 8 @end
 9 
10 @implementation ViewController
11 
12 - (void)viewDidLoad {
13     [super viewDidLoad];
14     
15     // 获取沙盒路径
16     self.path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0] stringByAppendingPathComponent:@"data.data"];
17 }
18 
19 // 归档保存对象
20 - (IBAction)save:(UIButton *)sender {
21     // 创建对象
22     Model *m = [[Model alloc] initWithName:@"测试" num:101];
23     
24     // 创建NSData(可变),NSKeyedArchiver(实现归档的对象)
25     NSMutableData *data = [NSMutableData data];
26     NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
27     
28     // 对象进行编码归档
29     [archiver encodeObject:m forKey:@"m"];
30     
31     // 归档完成(必需)
32     [archiver finishEncoding];
33     
34     // 写入沙盒路径文件中
35     [data writeToFile:self.path atomically:YES];
36 }
37 
38 // 反归档解码获取对象
39 - (IBAction)get:(UIButton *)sender {
40     // 创建NSData(可变), NSKeyedUnarchiver(实现反归档的对象)
41     NSMutableData *data = [NSMutableData dataWithContentsOfFile:self.path];
42     NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
43     
44     // 反归档解码获取对象
45     Model *m = [unarchiver decodeObjectForKey:@"m"];
46     
47     self.nameText.text = [NSString stringWithFormat:@"%@ %ld", m.name, m.num];
48 }
49 
50 - (void)didReceiveMemoryWarning {
51     [super didReceiveMemoryWarning];
52     // Dispose of any resources that can be recreated.
53 }
54 
55 @end

　　*.主要沙盒路径:

NSHomeDirectory----------------------->沙盒主路径
NSDocumentDirectory------------------->Documents文件夹
NSLibraryDirectory-------------------->Library文件夹
NSCachesDirectory--------------------->Caches文件夹
NSTemporaryDirectory------------------>tmp文件夹