New signal (preStateCreate), dispatched with FlxState as parameter

[j1mmie]

I found this useful while working on a game with dependency injection and would like to propose it for the main line. I wanted a single listener to detect every time the state has changed, and automatically inject dependencies into that state.

The solution was to create a new signal, preStateCreate, that includes the newly-change-to FlxState as the payload of the signal. This new signal is dispatched after the stateChange signal, and before the .create() method is called on the new state (hence, "pre state create").

[Gama11]

Thanks!

That's actually a very elegant solution to this problem (without any breaking API changes!). Some people simply add arguments to the FlxState child class constructors, but that breaks any usage of FlxG.resetState since that attempts to create a new instance using Reflection without any arguments.

There's also the option to use static variables, but that's kind of a hack as well.

[j1mmie]

Yeah I was originally adding an accessor to FlxGame for _newState, and using the old stateChanged signal. That seemed a bit hacky.

Thanks for the review. I'll check to see if there are some docs I can modify as a result of this addition.

[Gama11]

This also makes FlxSignal#addOnce() seem a lot more useful. :)