[FMX04] Key.addlistener?

1

I’m having trouble getting this part of Sen’s code to function! I attached his tutorial fla! I’ve searched in the AS help in Flash and tried modifying the Key.addlistener object but it still won’t respond to the arrow keys!

Sen’s code

// set the ball to recognize key presses and move based on them
Key.addListener(ball);
ball.onKeyDown = function(){
	var xmove, ymove;
	if (Key.isDown(Key.UP)){
		ymove = 1;
	}else if (Key.isDown(Key.DOWN)){
		ymove = -1;
	}else if (Key.isDown(Key.LEFT)){
		xmove = -1;
	}else if (Key.isDown(Key.RIGHT)){
		xmove = 1;
	}
	// update new position based on ball's current
	xmove += this.x;
	ymove += this.y;
	if (IsValidTile(xmove, ymove)){
		moveToGridSpace(xmove, ymove);
	}
}

My attempt

// set the ball to recognize key presses and move based on them
ball = new Object ();
ball.onKeyDown = function(){
	var xmove, ymove;
	if (Key.isDown(Key.UP)){
		ymove = 1;
	}else if (Key.isDown(Key.DOWN)){
		ymove = -1;
	}else if (Key.isDown(Key.LEFT)){
		xmove = -1;
	}else if (Key.isDown(Key.RIGHT)){
		xmove = 1;
	}
Key.addListener(ball);
	// update new position based on ball's current
	xmove += this.x;
	ymove += this.y;
	if (IsValidTile(xmove, ymove)){
		moveToGridSpace(xmove, ymove);
	}
}

What is wrong?