c++ GUI Events/Messaging Design

So, I'm making a simple game using DirectX 9 and C++. I looked at the SDK's GUI, but I think I can implement something simpler.

All I want are windows, labels, buttons, textboxes, and checkboxes.

I've created a base class GUIObject, that all inherit from. It includes basics like size and focus and whatnot. Then the derived classes, GUILabel for example, all define render(), update() and whatnot.

My question is how to handle events, like clicks? I had it working with GUILabel::Click() defining every possibility based on the current instance's text member value. It felt wrong and I realized that every single label that needed to be clicked would have to be defined in the GUILabel clas开发者_JAVA技巧s. I'd like to move that to each game state's code.

So, I briefly tried making the GUILabel::Click() take a function pointer as an argument. But then I realized I needed to have the state's class member method as static (not really possible, unless everything in it is static as well, right?) or also pass it a GUIObject class as well. Is that the way to go?

Could I define a derivation of GUILabel (or button, or whatnot) within a game state and just override whichever actions I needed? And then do that for whatever controls I need in that state?

What is the proper way to implement event handling?

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You might want to look into using a signaling library such as boost::signals to allow you the flexibility of defining the interface between your GUI objects and the underlying events that each callback will trigger. It can also come in handy for the reverse relationship where you need GUI elements such as status indicators, etc. to respond to underlying events.

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For callbacks/click events i would go with boost::function/boost::bind. In my GUI framework I used to have two different abstract classes InputHandler and Renderable for handling touches and rendering. This leads to a design where components which don't need to be clickable (like UILabel) wont need to implement useless methods.

HTH, Alex