Why can't I access public variables from other classes?

Question

I want to define my variables in my game document class, then use some of those variables in my Movement class. However, when I use these variables in my movement class I get tons of Compiling Errors saying that they're all undefined.

Thus my question is, why are my public variables not passed over to my other class? I have imported the class by doing import game; so this leaves me confussed. I'm probably just doing it wrong, but help is much appreciated.

Timeline

addChild((new Movement));

Game Document Class

package 
{
    import flash.display.MovieClip;
    import flash.utils.Timer;
    import flash.events.TimerEvent;

    public class game extends MovieClip
    {
        public var area1:Boolean = true;
        public var area2:Boolean = false;
        public var area3:Boolean = false;

        public var player1:Boolean = true;

        public var playerPosKeeper_mc:MovieClip = new mc_PlayerPosKeeper();

        public var up_dpad:MovieClip = new dpad_Up();
        public var down_dpad:MovieClip = new dpad_Down();
        public var left_dpad:MovieClip = new dpad_Left();
        public var right_dpad:MovieClip = new dpad_Right();
        public var menu_dpad:MovieClip = new dpad_Menu();
        public var run_dpad:MovieClip = new dpad_Menu();

        public var barrierRoof1_game:MovieClip = new game_BarrierRoof();
        public var barrierRoof2_game:MovieClip = new game_BarrierRoof();
        public var barrierSide1_game:MovieClip = new game_BarrierSide();
        public var barrierSide2_game:MovieClip = new game_BarrierSide();

        public function game()
        {
            trace("SUCCESS | Constructed Game Class");

        }
    }
}

Movement Class

package 
{
    import game;
    import flash.display.Stage;
    import flash.display.MovieClip;
    import flash.events.Event;
    import flash.events.TouchEvent;
    import flash.net.dns.AAAARecord;
    import flash.ui.Multitouch;
    import flash.ui.MultitouchInputMode;


    public class Movement extends MovieClip
    {
        var inMotion:Boolean = false;

        public function Movement()
        {
            trace("SUCCESS | Constructed Movement Class");

            addChild(playerPosKeeper_mc);
            playerPosKeeper_mc.x = 384;
            playerPosKeeper_mc.y = 46;

            addChild(up_dpad);
            up_dpad.x = 55;
            up_dpad.y = 336;

            addChild(down_dpad);
            down_dpad.x = 57;
            down_dpad.y = 432;

            addChild(left_dpad);
            left_dpad.x = 19;
            left_dpad.y = 372;

            addChild(right_dpad);
            right_dpad.x = 118;
            right_dpad.y = 372;

            addChild(menu_dpad);
            menu_dpad.x = 61;
            menu_dpad.y = 377;

            addChild(run_dpad);
            run_dpad.x = 684;
            run_dpad.y = 369;

            addChild(barrierRoof1_game);
            barrierRoof1_game.x = 0;
            barrierRoof1_game.y = 0;

            addChild(barrierRoof2_game);
            barrierRoof2_game.x = 0;
            barrierRoof2_game.y = 470;

            addChild(barrierSide1_game);
            barrierSide1_game.x = 0;
            barrierSide1_game.y = 0;

            addChild(barrierSide2_game);
            barrierSide2_game.x = 790;
            barrierSide2_game.y = 0;

            Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT;

            up_dpad.addEventListener(TouchEvent.TOUCH_BEGIN, moveUpTouchBEGIN);
            up_dpad.addEventListener(TouchEvent.TOUCH_END, moveUpTouchEND);

        }
        public function moveUpTouchBEGIN(e:TouchEvent):void
        {
            trace("Touch Began")
        }

        public function moveUpTouchEND(e:TouchEvent):void
        {
            trace("Touch Ended")
        }
    }

}

Answer 1

You are confused because "public" does not mean "global". Declaring variable as public means you want to grant an access to it to any entity, given the entity knows where that variable is.

Lets see what you have there.

• Top display object: stage.
• Main timeline: game is a child of stage.
• MovieClips up_dpad, down_dpad and so on, all are fields of the game instance.
• Movement: instance is a child of game.

In the Movement you are trying to access up_dpad and others, but they are kept as fields of game instance and have nothing to do with the Movement instance. That's why they are outside of Movement's addressing context.

So, if you want to have these variables declared as game fields, you need to address them from the Movement in a correct way.

Forget the timeline. In the Game (for the sake's sake never call classes in lowercase unless at the gunpoint) which is, I believe, a root document class:

    public function Game()
    {
        trace("SUCCESS | Constructed Game Class");

        // Pass reference to this instance to the constructor.
        var aMove:Movement = new Movement(this);

        // Add it as a child.
        addChild(aMove);
    }

In Movement:

    public function Movement(main:Game)
    {
        trace("SUCCESS | Constructed Movement Class");

        // Access variables inside Game instance via given reference.
        addChild(main.playerPosKeeper_mc);
        main.playerPosKeeper_mc.x = 384;
        main.playerPosKeeper_mc.y = 46;

        // ...and so on
    }

These are basics of Object Oriented Programming. If you want to access anything inside an object, you need to access the object first.