Yes, using your class; but with slight modifications. You just need to refer to the keys using String fields and assign them differently for each paddle. This would probably require you to pass the keys to the paddles when you create them using the constructor signature of 'Paddle(String, String)'. The constructor would store the keys in the fields and the movement code would check for the keys with those values to be down.

"up" and "down" are String literals. You can assign them to variables or fields using You could assign "w" and "s" just as well. However, these literals are not something that should be in the Paddle class. They should come from your world constructor when you create the Paddle objects. This could be used to pass the literal keys to the new Paddle object. The Paddle class constructor will then need to have these values saved in instance fields (fields that this new Paddle object will use). To give objects created from a class an instance field, you simply declare the field (not as 'static' -- ignore if you do not understand) within the class, but outside any methods. Now, each paddle will know what keys to use for movement

This is what I have so far and it isn't working for me. public class PongWorld extends World { String upKey = "up"; String downKey = "down"; /** * Constructor for objects of class PongWorld. * */ public PongWorld() { // Create a new world with 600x400 cells with a cell size of 1x1 pixels. super(400, 700, 1); addObject(new Ball(5),getWidth()/2,getHeight()/2); addObject(new Paddle("up","down"),20,getHeight()/2); addObject(new Paddle(),380,getHeight()/2); } public class Paddle extends Actor { private String upKey, downKey; public Paddle() { (String up, String down) upKey = up; downKey = down; GreenfootImage pad = new GreenfootImage(10, 100); pad.fill(); setImage(pad); } /** * Act - do whatever the Paddle wants to do. This method is called whenever * the 'Act' or 'Run' button gets pressed in the environment. */ public void act() { if(Greenfoot.isKeyDown("up")) { setLocation(getX(),getY()-5); } if(Greenfoot.isKeyDown("down")) { setLocation(getX(),getY()+5); } if(Greenfoot.isKeyDown("w")) { setLocation(getX(),getY()-5); } if(Greenfoot.isKeyDown("s")) { setLocation(getX(),getY()+5); } } }

Remove this from your PongWorld class: Your two 'addObject' lines for adding the paddles in the PongWorld constructor should look like this: In your Paddle class: Also, in the Paddle class, change your act method to this: