iOS-实现对象拷贝【对象拷贝】

对象引用 NSCopying 代理

.h

@interface xk : NSObject <NSCopying>

@property (nonatomic, copy) NSString *string1;
@property (nonatomic, copy) NSString *string2
@end

实现代理【拷贝】方法

.m

- (id)copyWithZone:(nullable NSZone *)zone {

xk *xk1= [[[self class] allocWithZone:zone] init];
xk1.string1 = [self.string1 copy];
xk1.string2 = [self.string2 copy];
return xk1;

}