iOS SDK - Reusing methods across multiple classes

Question

I'm trying to wrap my head around some of the OOP features in objective-c. It seems that using protocols is encouraged, while extending classes to add functionality is discouraged.

My problem:

I have some big chunks of code that scroll the screen when you click on a textfield. I don't want to put these huge chunks of code in every view controller. I just want to make some kind of reference to them.

Should I extend a parent class. Or use a protocol or what?

the whole protocol thing seems weird to me because it looks like it just tells you that you need to create more functions for a class without actually defining what the methods do.

I'm lost

Answer 1

I generally subclass UIViewController, put my code their, then inherit from that for the "concrete" view controllers.

But if you need to inherit from a subclass of UIViewController as well as UIViewController itself, you may want to consider putting the code in a category of UIViewController. But that also assumes that you don't need to add any property's to the class, since that is not possible in a category.

Answer 2

make them a class method by declaring them on .h file with this signature, then implementing them on .m file, with + they can be used across multiple class files, + can be thought like static method in other languages like Java

+ (return_type) someMethodName