协议可以在Objective-C中继承吗？

问题描述

我在框架目录的某些头文件中看到了这一点：

I saw this in some header file in the framework directory:

@interface NSCharacterSet : NSObject <NSCopying, NSMutableCopying, NSCoding>

@end

@interface NSMutableCharacterSet : NSCharacterSet <NSCopying, NSMutableCopying>

@end

我认为协议是可继承的。那，则无需在 NSMutableCharacterSet：NSCharacterSet 之后再次键入< NSCopying，NSMutableCopying> 。和NSMutableCharacterSet还符合NSCoding协议，对吗？

I thought protocols were inheritable.If I am right about that,There is no need to type <NSCopying, NSMutableCopying> again after "NSMutableCharacterSet : NSCharacterSet".And NSMutableCharacterSet also conforms to NSCoding protocol, right?

然后为什么苹果要再次键入？我犯错了吗？

Than why is Apple typing that again?Am I making mistake?

推荐答案

是的。子类也将采用相同的协议。

Yes. Subclasses will adopt the same protocols as well.

Apple再次键入该文本的原因是NSMutableCharacterSet已覆盖 -copyWithZone：和 -mutableCopyWithZone：。

The reason Apple typing that again is because NSMutableCharacterSet has overridden -copyWithZone: and -mutableCopyWithZone:.

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