Obstacle

/*
I'm using the Flixel port for Haxe NME. I'm having an issue with getting a collision callback function to work properly.

I have an Obstacle class that extends FlxSprite. Inside this class is a String called "message", and it's public. My callback function, obstacleTalk, originally accepted just two FlxObjects, and I referenced the "message" variable in the relevant FlxObject for the Obstacle. But this gave me an error that said "message" didn't exist in FlxObject (obviously).

So I tried changing the first parameter in the callback to be of type Obstacle, and I get a strange error message (see below).

In my main class, TopDownLevel, I have...
*/

/**
* Update each timestep
*/
override public function update():Void
{
    super.update();
    FlxG.collide(obstaclesGroup, player, obstacleTalk); // This is on line 259
}//

/**
* Talk to Obstacle/NPC
*/
private function obstacleTalk(obstacle:Obstacle, plyr:FlxObject):Void
{
    FlxG.log("message: "+obstacle.message);
    if(obstacle.message != "")
    {
        PlayState.chatWindow(obstacle.message);
    }
}//

/*
However, I cannot compile. I get this error in the terminal:

Source/TopDownLevel.hx:259: characters 2-52 : ?obstacle : Obstacle -> ?plyr : org.flixel.FlxObject -> Void should be Null<org.flixel.FlxObject -> org.flixel.FlxObject -> Void>
Source/TopDownLevel.hx:259: characters 2-52 : ?obstacle : Obstacle -> ?plyr : org.flixel.FlxObject -> Void should be org.flixel.FlxObject -> org.flixel.FlxObject -> Void
Source/TopDownLevel.hx:259: characters 2-52 : org.flixel.FlxObject should be Obstacle
Source/TopDownLevel.hx:259: characters 2-52 : For optional function argument 'NotifyCallback'
*/