The State Pattern – source files

I’m planning on doing a video tutorial on using the state pattern for better control over the state of your flash app. I put together what I’ll most likely use as the source files and I thought I’d share them here in case I don’t get around to making the video:

Part 1 – A typical “Document Class” approach to changing state
Focus on how it’s calling functions like “setStateAsWall()” to change state. Also notice how the .swf simply allows you to move from state to state.
View example
StatePattern – Part 1.zip

Part 2 – Adding the power of the State Pattern
Focus on how state is now changing using state.setStateAsWall(), then look into the individual State classes to set how they’re managing the state. In the .swf you’ll see you now how more control of how states move from state to state.
View example
StatePattern – Part 2.zip

Part 3 – Enforcing with an Interface
Focus on the interface “IState” (it’s like a class, but instead lists functions that any class that uses it has to have). Also notice that the State classes “implement” IState to enforce that they have the same functions. In the main class, you’ll see that they states are now typed as “IState”.
No change visually from part 2
StatePattern – Part 3.zip

I hope I get around to explaining this more later, but I thought I would push this up here before I go eat a bunch of turkey for Thanksgiving.

Tags: design patterns, state