Access of possibly undefined property graphics through a reference with static type flash.display:Stage.

[redgroupclan]

Having trouble doing a coding exercise. I'm trying to follow the commented-out instructions by putting my answers right below them, but I keep getting a compiler error saying "Scene 1, Layer 'actions', Frame 1, Line 42, Column 13 1119: Access of possibly undefined property graphics through a reference with static type flash.display:Stage." I have no idea what I'm supposed to put in front of the .graphics on with(stage.graphics) to make the code work, or whatever else I'm supposed to do. Can anyone help me?

import flash.display.Graphics;

var xDiff:Number;
var yDiff:Number;
var distance:Number;

stage.addEventListener(MouseEvent.MOUSE_DOWN, beginDrag);
stage.addEventListener(MouseEvent.MOUSE_UP, endDrag);
stage.addEventListener(MouseEvent.MOUSE_MOVE, enterFrm);

function beginDrag(evt:MouseEvent):void
{
if(evt.target.name == "hat" || evt.target.name == "ball")
    {
   evt.target.startDrag();
    }
}

function endDrag(event:MouseEvent):void
{
stopDrag();
}

function calcDistance(){
//Using the Pythagorean theorem, calculate the distance between the ball and the hat
//calculate and store the distance between the ball and the hat in the distance variable
//use the xDiff and yDiff variables in your calculation
xDiff = hat.x - ball.x;
yDiff = hat.y - ball.y;

distance = Math.sqrt(Math.pow(xDiff, 2) + Math.pow(yDiff, 2));

//place the distance in the distanceAmount text field, don't forget to use the String method and round off the calculated distance
distanceAmount.text = String(distance);
//If you prefer you may use the Point.distance method instead of the Pythagorean theorem
}

function enterFrm(event:MouseEvent):void
{
with(stage.graphics)
{
//use the graphics class to clear the screen
clear();

//use the graphics class and the lineStyle method to set a line style (use 3 for the thickness of the line, 0xFF0000 for the color and 1 for the alpha value
lineStyle(3, 0xFF0000, 1);

//use the graphics class and the moveTo method to move to the hat
moveTo(hat.x, 0);

//use the graphics class and the lineTo method to draw a line to the ball
lineTo(ball.x, ball.y);
}

calcDistance();
}

[kglad]

the error message is clear.  you can't use this:

with(stage.graphics)

because the stage doesn't have a graphics property.  only shape and sprite objects (and those that inherit from them like movieclip) can use the graphics property.

instead of stage, create a sprite and add it to the stage and apply your draw methods to the sprite.

[dmennenoh]

Just a mention re optimization - since you're calling calcDistance every frame, and seemingly calling it only from within your frame loop, I would inline the distance calc code that frame loop code. I'd also remove the call to Math.sqrt() and use the distance squared instead.