IPhone

 

     

之模型对象归档

 

 

 

    归档指的是另一种型式的序列化，但它是任保对象都可以实现的更常规的类型。

    其作用为：进行数据的持久化保存。

    对象必须实现 NSCodeing 协议和 NSCopying 协议。
  
@interface FourLines : NSObject <NSCoding, NSCopying> {
    NSString *field1;
    NSString *field2;
    NSString *field3;
    NSString *field4;   
}
@property (nonatomic, retain) NSString *field1;
@property (nonatomic, retain) NSString *field2;
@property (nonatomic, retain) NSString *field3;
@property (nonatomic, retain) NSString *field4;
@end
#pragma mark NSCoding
- (void)encodeWithCoder:(NSCoder *)encoder {
    [encoder encodeObject:field1 forKey:kField1Key];
    [encoder encodeObject:field2 forKey:kField2Key];
    [encoder encodeObject:field3 forKey:kField3Key];
    [encoder encodeObject:field4 forKey:kField4Key];
}
- (id)initWithCoder:(NSCoder *)decoder {
    if (self = [super init]) {
        self.field1 = [decoder decodeObjectForKey:kField1Key];
        self.field2 = [decoder decodeObjectForKey:kField2Key];
        self.field3 = [decoder decodeObjectForKey:kField3Key];
        self.field4 = [decoder decodeObjectForKey:kField4Key];
    }
    return self;
}
#pragma mark NSCopying
- (id)copyWithZone:(NSZone *)zone {
    FourLines *copy = [[[self class] allocWithZone: zone] init];
    copy.field1 = [[self.field1 copyWithZone:zone] autorelease];
    copy.field2 = [[self.field2 copyWithZone:zone] autorelease];
    copy.field3 = [[self.field3 copyWithZone:zone] autorelease];
    copy.field4 = [[self.field4 copyWithZone:zone] autorelease];