import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.border.*;import java.net.URL;import java.applet.*;public class Animator extends JApplet implements ActionListener {  JTextField jtfSpeed = new JTextField();  JTextField jtfPrefix = new JTextField();  JTextField jtfNumOfImages = new JTextField();  JTextField jtfAudioFile = new JTextField();  JButton jbtStartAnimation = new JButton("Start Animation");  PlayImage playImage = new PlayImage();  Image[] images;  AudioClip audioClip;  int sleepTime;  int numOfImages;     public void init() {         JPanel p = new JPanel();    p.setLayout(new GridLayout(4, 2));    p.add(new JLabel("Animation speed in milliseconds"));    p.add(jtfSpeed);    p.add(new JLabel("Image file prefix (只存有g)"));    p.add(jtfPrefix);    p.add(new JLabel("Number of images (<=24)"));    p.add(jtfNumOfImages);    p.add(new JLabel("Audio file"));    p.add(jtfAudioFile);    p.setBorder(new TitledBorder(      "Enter information for animation"));         JPanel jpButton = new JPanel();    jpButton.setLayout(new FlowLayout(FlowLayout.RIGHT));    jpButton.add(jbtStartAnimation);    JPanel p1 = new JPanel();    JPanel p2 = new JPanel();    JPanel p3 = new JPanel();    p1.setLayout(new BorderLayout());    p2.setLayout(new FlowLayout(FlowLayout.RIGHT));    p2.add(jpButton);    p1.add(p2,BorderLayout.NORTH);    p1.add(playImage,BorderLayout.CENTER);        getContentPane().setLayout(new GridLayout(2,1));    getContentPane().add(p1  );    getContentPane().add(p );         jbtStartAnimation.addActionListener(this);  }     public void actionPerformed(ActionEvent e) {    startAnimation();  }  public void startAnimation() {    MediaTracker imageTracker = new MediaTracker(this);         Toolkit toolkit = Toolkit.getDefaultToolkit();    URL url = null;    String prefix = jtfPrefix.getText().trim();    numOfImages =      new Integer(jtfNumOfImages.getText().trim()).intValue();    String audioFile = jtfAudioFile.getText().trim();    sleepTime = new Integer(jtfSpeed.getText().trim()).intValue();         images = new Image[numOfImages];    for (int i=0; i<images.length; i++) {             url = this.getClass().getResource("image/" + prefix + (i+1)        + ".gif");      images[i] = toolkit.getImage(url);             imageTracker.addImage(images[i], i);    }        try {      url = this.getClass().getResource(audioFile);    }    catch (Exception ex) {      System.out.println(ex);    }    System.out.println("url = " + url);    audioClip = Applet.newAudioClip(url);         try {      imageTracker.waitForAll();    }    catch (InterruptedException ex) {      System.out.println(ex);    }        imageTracker = null;         playImage.beginAnimation();  }     public static void main(String[] args) {         JFrame frame = new JFrame("Animator");         Animator applet = new Animator();        frame.getContentPane().add(applet, BorderLayout.CENTER);    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        applet.init();    applet.start();        frame.setSize(500, 400);    frame.setVisible(true);  }  class PlayImage extends JPanel implements Runnable {    private Thread thread = null;    int currentImageIndex = 0;    Image imageToDisplay;         protected boolean suspended = false;         public PlayImage() {             currentImageIndex = 0;      thread = new Thread(this);      setBorder(new LineBorder(Color.yellow, 1));    }    public void beginAnimation() {      thread.start();      if (audioClip != null) audioClip.loop();    }    public void start() {      resume();    }    public void stop() {      suspend();    }    public synchronized void resume() {      if (suspended) {        suspended = false;        notify();      }    }    public synchronized void suspend() {      suspended = true;    }    public void destroy() {      thread = null;    }    public void run() {      while (true) {        imageToDisplay =          images[currentImageIndex%numOfImages];                 if (currentImageIndex == 0) currentImageIndex = 52;        currentImageIndex = currentImageIndex + 1;        repaint();        try {          thread.sleep(sleepTime);          synchronized (this) {            while (suspended)              wait();          }        }        catch (InterruptedException ex) {        }      }    }         public void paintComponent(Graphics g) {      super.paintComponent(g);      if (imageToDisplay != null) {        g.drawImage(imageToDisplay, 0, 0, getSize().width,          getSize().height, this);      }    }  }}