Æliens

    private function init():void {
     ball = new Sprite();
     addChild(ball);
     ball.graphics.beginFill(0xff0000);
     ball.graphics.drawCircle(0, 0, 40);
     ball.graphics.endFill();
     ball.x = stage.stageWidth / 2;
     ball.y = stage.stageHeight / 2;
     stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyboardEvent);
    }
  

    public function onKeyboardEvent(event:KeyboardEvent):void {
     switch(event.keyCode) {
      case Keyboard.UP :
      ball.y -= 10;
      break;
       
      case Keyboard.DOWN :
      ball.y += 10;
      break;
      
      case Keyboard.LEFT :
      ball.x -= 10;
      break;
      
      case Keyboard.RIGHT :
      ball.x += 10;
      break;
      
      default:
      break;
     }
    }
   }
  }