Question

I need to split my job with my partner for designing game stages, and we badly need to use plist. So, say I have 20 different types of classes from which I need to dynamically instantiate objects in runtime. A particular class will be selected from plist input and an object of the class will be created on the fly.

The first thing that went through my mind was switch() and that was a bit dated I guess.

So I searched Stack Overflow and realized that iOS had NSClassFromString and objc_getclass.

• Create a class at runtime – Why do NSClassFromString AND objc_getclass return nil ?
• NSClassFromString returns nil

After few tries, I can tell NSClassFromString is really nice since I can just say what class I want upfront in plist and bam! there we go. Setting object properties is done with KeyValue dictionary after that and it’s all done like a magic.

My question is, how can I call class methods (those that start with +) if you’re to create objects this way? I’ve looked up documents and there is NSSelectorFromString(). But isn’t it for an instance rather than a class?

Answer 1

You can call performSelector: on a class.

For example you can call:

[NSClassFromString(@"UIViewController") performSelector:NSSelectorFromString(@"setToolbarItems:")]