iOS中复杂对象对象的归档返归档

iOS中复杂对象对象的归档返归档

归档与返归档听起来高大上,说的简单一些就是较之字符串,字典,数组等更复杂对象的写入与读取.

这里的复杂对象说的是Foundation框架内不存在类,假如我们自定义了一个类继承于NSObject

@interface Person : NSObject

@property (nonatomic,copy) NSString *name;

@property (nonatomic,copy) NSString *sex;

@end

Person有两个属性name,sex

在ViewController的viewDidLoad方法中

我们创建两个对象

Person *p = [[Personalloc] init];

    p.name =@"霸王";

    p.sex = @"男";

    

Person *p1 = [[Personalloc] init];

    p1.name = @"铁锤";

    p1.sex = @"女";

这时候我们想以NSData类型保存这两个对象就需要用到NSKeyedArchiver类,读取用到NSKeyedUnarchiver注意两者的区别

接下来我们开始

第一步:

在自定义的类中接受协议<NSCoding>

@interface Person :NSObject<NSCoding>

@property (nonatomic,copy)NSString *name;

@property (nonatomic,copy)NSString *sex;

@end

第二步:在Person.m中实现两个方法

归档(写入)

-(void)encodeWithCoder:(NSCoder *)aCoder{

    [aCoder encodeObject:self.nameforKey:@"name"];

    [aCoder encodeObject:self.sexforKey:@"sex"];

    

}

返归档(读取)

-(instancetype)initWithCoder:(NSCoder *)aDecoder{

    

    NSLog(@"调用了返归档方法");

    self = [superinit];

    if (self) {

        self.name = [aDecoderdecodeObjectForKey:@"name"];

        self.sex = [aDecoderdecodeObjectForKey:@"sex"];

    }

    return self;

}

第三步:

写入

回到ViewController的viewDidLoad方法中

    //NSDdata对象初始化

    NSMutableData *data = [NSMutableDatadata];

    //使用归档工具

    NSKeyedArchiver *archiver = [[NSKeyedArchiveralloc] initForWritingWithMutableData:data];

    [archiver encodeObject:p forKey:@"p"];

    [archiver encodeObject:p1 forKey:@"p1"];

    // 标志归档结束

    [archiver finishEncoding];

    // 保存到Document下person.dat中

    NSString *path =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES)[0];

    path = [path stringByAppendingString:@"/person.dat"];

    NSLog(@"%@",path);

    [data writeToFile:pathatomically:YES];

读取

    NSData *readData = [[NSDataalloc] initWithContentsOfFile:path]; // path是上文中路径

    // 返归档用到的工具

    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiveralloc] initForReadingWithData:readData];

    Person *pp = [unarchiver decodeObjectForKey:@"p"];

    Person *pp1 = [unarchiver decodeObjectForKey:@"p1"];

    NSLog(@"%@--%@",pp.name,pp.sex);

    NSLog(@"%@--%@",pp1.name,pp1.sex);