How do I create a custom class from a class that already exists? (Existing class does not support NSCoding)

What I'm trying to do is convert an EKEvent into NSData, and then convert it back into an EKEvent.

I looked around and noticed that in order to use NSKeyedArchiver, the class must conform to the NSCoding protocol. I als开发者_如何学Goo found that if I was creating a custom class, I could make it conform to the NSCoding protocol by implementing encodeWithCoder: on such a custom class.

Essentially, I assume that in order to convert my EKEvent to NSData and back, I will need to create a custom class (let us call it CustomEvent) I need to do the following:

EKEvent --> CustomEvent --> NSData --> CustomEvent --> EKEvent

Can I get any help on learning how to create a custom class which DUPLICATES an existing class with the exception that I implement encodeWithCoder: to make it conform to NSCoding?

I'm looking at EKEvent.h, and I know that it involves other classes which I must also duplicate (because they too don't conform to NSCoding). Can anyone send me a tutorial link or help me out?

Thanks in advance!

What you're describing appears to be a subclass.

However, in Objective-C, you have the simpler option of defining a category on an existing class to add the functionality you want.