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

Question

Hey all!

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 also 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!

Answer 1

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.