Small Image flipping(like a screensaver) app...have easy ? about expansion

Question

Working on code from:
http://www.rscc.cc.tn.us/faculty/bell/Cst218/jhtp16.html
have included it below, just created a directory named images
and copy/past 8 images into that directory, and rename them bug#.gif, starting at bug0, bug1, bug2...up until bug7.gif
Run app, it works, fine, it flips through the images
HOWEVER, of course, while learning/doing I found it inconvenient to have to rename all of the images, and thought of screensaver programs that flips images for you, and was trying to figure out what I'd have to do to make it possible to just load an arbitrary amount/named image files to be able to flip them.
I figure some kind of JFileChooser would have to be integrated, and then somehow, each file would have to be imported into an Array or Vector set.....
See...that's an entirely different program....but would be interested in the above, and how I could change the code to allow ANY named image, not just images named "bug" , be apart of the array.
Somehow, read the entire directory, and import each image into the Array, or a Vector/whatever.....
While I understand this program ..my "programming brain" /skills are not developed enough to implement the system..hence posting :)
Thank you for your time...
//http://www.rscc.cc.tn.us/faculty/bell/Cst218/jhtp16.html
// LogoAnimator.java
// Animation a series of images
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LogoAnimator extends JPanel
                          implements ActionListener {
   protected ImageIcon images[];
   protected int totalImages = 8,   //changed from 30 to 8
                 currentImage = 0,
                 animationDelay = 1500; // 50 millisecond delay
   protected Timer animationTimer;
   public LogoAnimator()
      setSize( getPreferredSize() );
      images = new ImageIcon[ totalImages ];
      for ( int i = 0; i < images.length; ++i )
         images[ i ] =
            new ImageIcon( "images/bug" + i + ".gif" );  //?!?! here, in this program, each file would have to be named "bug#"
      startAnimation();
   public void paintComponent( Graphics g )
      super.paintComponent( g );
      if ( images[ currentImage ].getImageLoadStatus() ==
           MediaTracker.COMPLETE ) {
         images[ currentImage ].paintIcon( this, g, 0, 0 );
         currentImage = ( currentImage + 1 ) % totalImages;
   public void actionPerformed( ActionEvent e )
      repaint();
   public void startAnimation()
      if ( animationTimer == null ) {
         currentImage = 0;
         animationTimer = new Timer( animationDelay, this );
         animationTimer.start();
      else  // continue from last image displayed
         if ( ! animationTimer.isRunning() )
            animationTimer.restart();
   public void stopAnimation()
      animationTimer.stop();
   public Dimension getMinimumSize()
      return getPreferredSize();
   public Dimension getPreferredSize()
      return new Dimension( 160, 80 );
   public static void main( String args[] )
      LogoAnimator anim = new LogoAnimator();
      JFrame app = new JFrame( "Animator test" );
      app.getContentPane().add( anim, BorderLayout.CENTER );
      app.addWindowListener(
         new WindowAdapter() {
            public void windowClosing( WindowEvent e )
               System.exit( 0 );
      // The constants 10 and 30 are used below to size the
      // window 10 pixels wider than the animation and
      // 30 pixels taller than the animation.
      app.setSize( anim.getPreferredSize().width + 10,
                   anim.getPreferredSize().height + 30 );
      app.show();
}

Answer 1

This is set up to compile and run in j2se 1.4
You can swap the comments in three marked areas to compile and run in j2se 1.5
If using earlier versions than j2se 1.4 you'll need to replace the image loading code (2 lines, marked)
with earlier code, such as ImageIcon (j2se 1.2) or the earlier Toolkit methods with MediaTracker.
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import java.util.*;
import java.util.List;
import javax.imageio.ImageIO;
import javax.imageio.stream.FileImageInputStream;
import javax.swing.*;
public class SlideShow
    SlidePanel slidePanel;
    JFileChooser fileChooser;
    JComboBox slides;
    JFrame f;
    public SlideShow()
        slidePanel = new SlidePanel();
        f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(getSlidePanel(), "North");
        f.getContentPane().add(slidePanel);
        f.getContentPane().add(getControlPanel(), "South");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    private JPanel getSlidePanel()
        fileChooser = new JFileChooser("images/");
        slides = new JComboBox();
        Dimension d = slides.getPreferredSize();
        d.width = 125;
        slides.setPreferredSize(d);
        final JButton
            open   = new JButton("open"),
            remove = new JButton("remove");
        ActionListener l = new ActionListener()
            public void actionPerformed(ActionEvent e)
                JButton button = (JButton)e.getSource();
                if(button == open)
                    showDialog();
                if(button == remove)
                    removeSlide();
        open.addActionListener(l);
        remove.addActionListener(l);
        JPanel panel = new JPanel();
        panel.add(open);
        panel.add(slides);
        panel.add(remove);
        return panel;
    private JPanel getControlPanel()
        final JButton
            start = new JButton("start"),
            stop  = new JButton("stop");
        ActionListener l = new ActionListener()
            public void actionPerformed(ActionEvent e)
                JButton button = (JButton)e.getSource();
                if(button == start)
                    slidePanel.start();
                if(button == stop)
                    slidePanel.stop();
        start.addActionListener(l);
        stop.addActionListener(l);
        JPanel panel = new JPanel();
        panel.add(start);
        panel.add(stop);
        return panel;
    private void showDialog()
        if(fileChooser.showOpenDialog(f) == JFileChooser.APPROVE_OPTION)
            File file = fileChooser.getSelectedFile();
            if(hasValidExtension(file))
                Slide slide = new Slide(file);
                slides.addItem(slide);
                slides.setSelectedItem(slide);
                slidePanel.addImage(slide.getFile());
    private boolean hasValidExtension(File file)
        String[] okayExtensions = { "gif", "jpg", "png" };
        String path = file.getPath();
        String ext = path.substring(path.lastIndexOf(".") + 1).toLowerCase();
        for(int j = 0; j < okayExtensions.length; j++)
            if(ext.equals(okayExtensions[j]))
                return true;
        return false;
    private void removeSlide()
        Slide slide = (Slide)slides.getSelectedItem();
        int index = slides.getSelectedIndex();
        slides.removeItem(slide);
        slidePanel.removeImage(index);
    public static void main(String[] args)
        new SlideShow();
class Slide
    File file;
    public Slide(File file)
        this.file = file;
    public File getFile()
        return file;
    public String toString()
        return file.getName();
class SlidePanel extends JPanel
    //List<BufferedImage> images;  // j2se 1.5
    List images;                   // j2se 1.4
    int count;
    boolean keepRunning;
    Thread animator;
    public SlidePanel()
        //images = Collections.synchronizedList(new ArrayList<BufferedImage>());  // 1.5
        images = Collections.synchronizedList(new ArrayList());  // j2se 1.4
        count = 0;
        keepRunning = false;
        setBackground(Color.white);
    protected void paintComponent(Graphics g)
        super.paintComponent(g);
        int w = getWidth();
        int h = getHeight();
        if(images.size() > 0)
            //BufferedImage image = images.get(count);               // j2se 1.5
            BufferedImage image = (BufferedImage)images.get(count);  // j2se 1.4
            int imageWidth = image.getWidth();
            int imageHeight = image.getHeight();
            int x = (w - imageWidth)/2;
            int y = (h - imageHeight)/2;
            g.drawImage(image, x, y, this);
    private Runnable animate = new Runnable()
        public void run()
            while(keepRunning)
                if(images.size() == 0)
                    stop();
                    break;
                count = (count + 1) % images.size();
                repaint();
                try
                    Thread.sleep(1000);
                catch(InterruptedException ie)
                    System.err.println("animate interrupt: " + ie.getMessage());
            repaint();
    public void start()
        if(!keepRunning)
            keepRunning = true;
            animator = new Thread(animate);
            animator.start();
    public void stop()
        if(keepRunning)
            keepRunning = false;
            animator = null;
    public void addImage(File file)
        try
            FileImageInputStream fiis = new FileImageInputStream(file);  // j2se 1.4+
            images.add(ImageIO.read(fiis));                              //    "
        catch(FileNotFoundException fnfe)
            System.err.println("file: " + fnfe.getMessage());
        catch(IOException ioe)
            System.err.println("read: " + ioe.getMessage());
    public void removeImage(int index)
        images.remove(index);
}