啰嗦的NSCoding实现

@interface XXModel : NSObject <NSCoding> { 

}

- (void)encodeWithCoder:(NSCoder *)encoder;

- (id)initWithCoder:(NSCoder *)decoder;

@end

 

继承XXModel，避免每次用到NSCoding都去写NSCoding两个实现。具体实现用Ivar* ivars = class_copyIvarList(cls, &numberOfIvars);

perfect。