[hardwired]

Code:

//  <applet code="FullBallRx" width="400" height="400"></applet>
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Random;

public class FullBallRx extends Applet implements Runnable {
   
    //position of the ball
    int x_pos = 12;
    int y_pos = 12;
    
    //position of the ball ** slider **
    int sliderx_pos = 1;
    int slidery_pos = 150;
    
    //ball size
    int radius = 5;
    
    //size of slider
    int swidth = 60;
    int sheight = 1;
    Rectangle box = new Rectangle(swidth, sheight);

//    int realwidth = sliderx_pos + swidth;
   
    //balldirection
    int x_speed = 6;
    int y_speed = 8;
    
    //slider direcion
    int sliderx_speed = 0;
    
    //applet size
    int appletsize_top = 10;
    int appletsize_bottom = 160;  
    int appletsize_left = 10;  
    int appletsize_right = 340; 
   
    //random movement
    Random rnd = new Random ();
    
    //Drawing image off screen
    private Image dbImage;
    private Graphics dbg;

    Thread thread;
    boolean running = false;

    public void init()
    {
        enableEvents(AWTEvent.KEY_EVENT_MASK);
        setFocusable(true);
    }
  
    public void start ()
    {
        // define a new thread 
        running = true;
        thread = new Thread (this);
        // start this thread
        thread.start ();
        System.out.println("start");
    }

    public void stop()
    {
        running = false;
        if(thread != null)
            thread.interrupt();
        thread = null;
        System.out.println("stop");
    }

    public void run () 
    {
        while (running)
        {
            // lower ThreadPriority 
//            Thread.currentThread().setPriority(Thread.MIN_PRIORITY);

            // change direction if ball will hit any side on the
            // next advance/stop. The ball position is at its center.
             if (x_pos - radius + x_speed < appletsize_left ||
                 x_pos + radius + x_speed > appletsize_right )
	    {
                x_speed *= -1;
            }

            if (y_pos - radius + y_speed < appletsize_top)
	    {
                y_speed *= -1;
            }
            
            if(y_pos + radius + y_speed > appletsize_bottom )
            {
               y_speed *= -1;
            }

            //change direction of slider
            // Moved to processKeyEvent method.

            //logic for bouncing off slider
            // We know where the ball and slider are so we
            // should be able to calculate a possible collision.
            // Look ahead to the next position of the ball for
            // the possible collision.
            // Assumption: consider collisions only on the top
            // of the slider.
            
            if(x_pos + radius + x_speed > sliderx_pos &&
               x_pos - radius + x_speed < sliderx_pos + swidth) {
                // Ball is in vertical plane of slider.
                // Check for possible vertical contact.
                if(y_pos + radius + y_speed > slidery_pos) {
                    // We have an imminent collision -> bounce!
                    y_speed *= -1;
                }
            }

            x_pos += x_speed;
            y_pos += y_speed;

            //repaint applet
            repaint();

            try
            {
                // Stop thread for the speed
                Thread.sleep (50);
            }
            catch (InterruptedException ex)
            {
                running = false;
                break;
            }

            // set ThreadPriority to maximum value
//            Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
        }
    }

    //create an image off screen and loads it into the applet
    public void update (Graphics g)
    {
        // initialize buffer
        if (dbImage == null)
        {
            dbImage = createImage (this.getSize().width, this.getSize().height);
            dbg = dbImage.getGraphics ();
        }

        // clear screen in background
        dbg.setColor (getBackground ());
        dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);

        // draw elements in background
        dbg.setColor (getForeground());
        paint (dbg);

        // draw image on the screen
        g.drawImage (dbImage, 0, 0, this);
    }

   
    public void paint (Graphics g) 
    { 
        Graphics2D g2 = (Graphics2D) g;
        // set color
        g.setColor (Color.red);

        // paint a filled colored circle
        g.fillOval (x_pos - radius, y_pos - radius, 2 * radius, 2 * radius);

        box.setLocation(sliderx_pos, slidery_pos);
        g2.setColor (Color.blue);
        g2.draw(box);
    }

    protected void processKeyEvent(KeyEvent e)
    {
        int keyCode = e.getKeyCode();
        // linke Cursortaste
        if (keyCode == KeyEvent.VK_LEFT)
        {
            // Ball bewegt sich dann nach links
            if (sliderx_pos -10 > appletsize_left)
                sliderx_pos = sliderx_pos -10;
        }
        // rechte Cursortaste
        else if (keyCode == KeyEvent.VK_RIGHT)
        {
            if (sliderx_pos + swidth +10 < appletsize_right)
                sliderx_pos = sliderx_pos +10;
        }
    } 
}