归档

归档也叫序列化，就是把对象、变量以一定的格式写入文件中进行存储，等到需要的时候直接读取出来，还原原数据的格式。ios中主要有以下几种方法实现归档:

一、对单个对象进行归档

1. 归档

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"apple",@"one",@"samsung",@"two",@"xiaomi",@"three",@"HTC",@"four", nil];
//1.获取文件路径
NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
//2.添加储存的文件名
NSString *path  = [docPath stringByAppendingPathComponent:@"data.archiver"];
//归档字典
BOOL flag = [NSKeyedArchiver archiveRootObject:dict toFile:path];

2. 解档

//传入路径进行解档
[NSKeyedUnarchiver unarchiveObjectWithFile:path];

这种方法只能对单个对象归档，不能归档多个对象

二、对多个对象的归档

1. 归档

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"apple",@"one",@"samsung",@"two",@"xiaomi",@"three",@"HTC",@"four", nil];
NSArray *array = [NSArray arrayWithObjects:@"one",@"two",@"three", nil];
//1.获取文件路径
NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
//2.添加储存的文件名
NSString *path  = [docPath stringByAppendingPathComponent:@"data.archiver"];
//初始化
NSMutableData *data = [[NSMutableData alloc] init];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
[archiver encodeObject:dict forKey:@"dict"];
[archiver encodeObject:array forKey:@"array"];
//完成归档
[archiver finishEncoding];
[data writeToFile:path atomically:YES];

2. 解档

//传入路径
NSData *data = [[NSData alloc] initWithContentsOfFile:path];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
//开始解档
[unarchiver decodeObjectForKey:@"array"];
[unarchiver decodeObjectForKey:@"dict"];
//完成解档
[unarchiver finishDecoding];

这种方法能归档基本数据类型，但不能对自定义类生成的对象进行归档

三、对自定义对象进行归档

1. 创建Person类,定义属性，并且遵循NSCoding协议

@interface Person : NSObject<NSCoding>
//姓名
@property (nonatomic,copy) NSString *name;
//性别
@property (nonatomic,copy) NSString *sex;
//年龄
@property (nonatomic,assign) int age;
@end

2. 实现NSCoding协议方法

@implementation Person
//对person对象进行归档时,此方法执行
- (void)encodeWithCoder:(NSCoder *)aCoder{
    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeObject:self.sex forKey:@"sex"];
    [aCoder encodeInt:self.age forKey:@"age"];
}
//对person对象进行反归档时,该方法执行
- (instancetype)initWithCoder:(NSCoder *)coder{
    self = [super init];
    if (self) {
        self.name = [coder decodeObjectForKey:@"name"];
        self.sex = [coder decodeObjectForKey:@"sex"];
        self.age = [coder decodeIntForKey:@"age"];
    }
    return self;
}
- (NSString *)description{
    return [NSString stringWithFormat:@"%@,%@,%d",self.name,self.sex,self.age];
}
@end

3. 复杂对象写入文件，实现归档、解档

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.view.backgroundColor = [UIColor whiteColor];
    
    Person *person = [[Person alloc] init];
    person.name = @"xiaomeng";
    person.sex = @"男";
    person.age = 17;
    
    //路径
    NSString *path = [NSHomeDirectory() stringByAppendingString:@"person.plist"];
    
    //归档
    [NSKeyedArchiver archiveRootObject:person toFile:path];
    //解档
    person = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
    NSLog(@"%@",person);//xiaomeng,男,17
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
@end

源码地址