GamerPanel.java

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class GamerPanel extends JPanel
{  
    private Gamer game;
    private int level;
    private int xChange;
    private int yChange;
    
    public GamerPanel()
    {
        setBackground(Color.WHITE);
        setPreferredSize(new Dimension(900, 900));
        
        game = new Gamer();
        level = 1;
        xChange = 3;
        yChange = 3;
        game.setSquares(level);
        
        setFocusable(true);
        addKeyListener(new KeyStrokeListener());
    }
    
    public void paintComponent(Graphics g)
    {
        Graphics2D g2 = (Graphics2D) g;
        super.paintComponent(g2);
        game.draw(g2);
    }
    
    public void moveBall(int x, int y)
    {
        game.moveBall(x, y);
        repaint();
    }
    
    
    class KeyStrokeListener implements KeyListener
    {
        public void keyPressed(KeyEvent event) 
        {
            String key = KeyStroke.getKeyStrokeForEvent(event).toString().replace("pressed ", ""); 
            if (key.equals("DOWN"))
            {
                moveBall(0, yChange);
            }
            else if (key.equals("UP"))
            {
                moveBall(0, -yChange);            
            }
            else if (key.equals("LEFT"))
            {
                moveBall(-xChange, 0);            
            }
            else if (key.equals("RIGHT"))
            {
                moveBall(xChange, 0);            
            }
            else if (key.equals("ENTER"))
            {
                if (game.checkVictory())
                {
                    level++;
                    game.setSquares(level);
                    xChange += 5;
                    yChange += 5;
                }
            }
            if (game.checkCollision())
            {
                game.resetBall();
            }
            repaint();
        }

        public void keyTyped(KeyEvent event) {}

        public void keyReleased(KeyEvent event) {}
    }
}