import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.*;
import java.util.Random;

import javax.swing.JApplet;

@SuppressWarnings("serial")
public class MovingBox extends JApplet implements Runnable, KeyListener
{
    int gameStatus;
    int boxX = 150, boxY = 100;
    private Image dbImage;
    private Graphics dbg;
    public void init()
    {
        this.addKeyListener(this);
        this.setSize(440,440);
    }

    public void start()
    {
        Thread th = new Thread(this);
        th.start();
    }

    public void run()
    {
        int directionX = 0;
        int directionY = 0;

        while (gameStatus ==0 ) {
            if (gameStatus ==1){break;}
        }

        for (int i=1 ; i<1000000; i++){

            if ( i % 200 < 100 ){
                directionX = 1;
            }
            if ( i % 200 > 100 && i %200 <200  ){
                directionX = -1;
            }

            boxX += directionX;
            boxY += directionY;
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        repaint();
    }}

     public void paint(Graphics g){
        g.setColor(Color.white);
        g.fillRect(20,20,400,400);
        g.setColor(Color.BLUE);
        g.fillRect(boxX, boxY, 30, 30);
     }

    public void update(Graphics g)
    {
        if (dbImage == null){
            dbImage = createImage (this.getSize().width, this.getSize().height);
            dbg = dbImage.getGraphics ();
        }
        dbg.setColor (getBackground ());
        dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);
        dbg.setColor (getForeground());
        paint (dbg);
        g.drawImage (dbImage, 0, 0, this);
    }

    public void keyTyped(KeyEvent e) {}
    public void keyReleased(KeyEvent arg0) {}
    public void keyPressed(KeyEvent e) {
        int key = e.getKeyCode();
    if(gameStatus==0) {
            if(key==KeyEvent.VK_SPACE) {
                gameStatus = 1;
            }
        }
    }
}