import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.event.*;/* * SliderDemo.java is a 1.4 application that requires all the * files in the images/doggy directory. */public class SliderDemo extends JPanel                        implements ActionListener,                                   WindowListener,                                   ChangeListener {    //Set up animation parameters.    static final int FPS_MIN = 0;    static final int FPS_MAX = 30;    static final int FPS_INIT = 15;    //initial frames per second    int frameNumber = 0;    int NUM_FRAMES = 14;    ImageIcon[] images = new ImageIcon[NUM_FRAMES];    int delay;    Timer timer;    boolean frozen = false;    //This label uses ImageIcon to show the doggy pictures.    JLabel picture;    public SliderDemo() {        setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));        delay = 1000 / FPS_INIT;        //Create the label.        JLabel sliderLabel = new JLabel("Frames Per Second", JLabel.CENTER);        sliderLabel.setAlignmentX(Component.CENTER_ALIGNMENT);        //Create the slider.        JSlider framesPerSecond = new JSlider(JSlider.HORIZONTAL,                                              FPS_MIN, FPS_MAX, FPS_INIT);        framesPerSecond.addChangeListener(this);        //Turn on labels at major tick marks.        framesPerSecond.setMajorTickSpacing(10);        framesPerSecond.setMinorTickSpacing(1);        framesPerSecond.setPaintTicks(true);        framesPerSecond.setPaintLabels(true);        framesPerSecond.setBorder(                BorderFactory.createEmptyBorder(0,0,10,0));        //Create the label that displays the animation.        picture = new JLabel();        picture.setHorizontalAlignment(JLabel.CENTER);        picture.setAlignmentX(Component.CENTER_ALIGNMENT);        picture.setBorder(BorderFactory.createCompoundBorder(                BorderFactory.createLoweredBevelBorder(),                BorderFactory.createEmptyBorder(10,10,10,10)));        updatePicture(0); //display first frame        //Put everything together.        add(sliderLabel);        add(framesPerSecond);        add(picture);        setBorder(BorderFactory.createEmptyBorder(10,10,10,10));        //Set up a timer that calls this object's action handler.        timer = new Timer(delay, this);        timer.setInitialDelay(delay * 7); //We pause animation twice per cycle                                          //by restarting the timer        timer.setCoalesce(true);    }    /** Add a listener for window events. */    void addWindowListener(Window w) {        w.addWindowListener(this);    }    //React to window events.    public void windowIconified(WindowEvent e) {        stopAnimation();    }    public void windowDeiconified(WindowEvent e) {        startAnimation();    }    public void windowOpened(WindowEvent e) {}    public void windowClosing(WindowEvent e) {}    public void windowClosed(WindowEvent e) {}    public void windowActivated(WindowEvent e) {}    public void windowDeactivated(WindowEvent e) {}    /** Listen to the slider. */    public void stateChanged(ChangeEvent e) {        JSlider source = (JSlider)e.getSource();        if (!source.getValueIsAdjusting()) {            int fps = (int)source.getValue();            if (fps == 0) {                if (!frozen) stopAnimation();            } else {                delay = 1000 / fps;                timer.setDelay(delay);                timer.setInitialDelay(delay * 10);                if (frozen) startAnimation();            }        }    }    public void startAnimation() {        //Start (or restart) animating!        timer.start();        frozen = false;    }    public void stopAnimation() {        //Stop the animating thread.        timer.stop();        frozen = true;    }    //Called when the Timer fires.    public void actionPerformed(ActionEvent e) {        //Advance the animation frame.        if (frameNumber == (NUM_FRAMES - 1)) {            frameNumber = 0;        } else {            frameNumber++;        }        updatePicture(frameNumber); //display the next picture        if ( frameNumber==(NUM_FRAMES - 1)          || frameNumber==(NUM_FRAMES/2 - 1) ) {            timer.restart();        }    }    /** Update the label to display the image for the current frame. */    protected void updatePicture(int frameNum) {        //Get the image if we haven't already.        if (images[frameNumber] == null) {            images[frameNumber] = createImageIcon("images/doggy/T"                                                  + frameNumber                                                  + ".gif");        }        //Set the image.        if (images[frameNumber] != null) {            picture.setIcon(images[frameNumber]);        } else { //image not found            picture.setText("image #" + frameNumber + " not found");        }    }    /** Returns an ImageIcon, or null if the path was invalid. */    protected static ImageIcon createImageIcon(String path) {        java.net.URL imgURL = SliderDemo.class.getResource(path);        if (imgURL != null) {            return new ImageIcon(imgURL);        } else {            System.err.println("Couldn't find file: " + path);            return null;        }    }    /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event-dispatching thread.     */    private static void createAndShowGUI() {        //Make sure we have nice window decorations.        JFrame.setDefaultLookAndFeelDecorated(true);        //Create and set up the window.        JFrame frame = new JFrame("SliderDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.        SliderDemo animator = new SliderDemo();        animator.setOpaque(true); //content panes must be opaque        frame.setContentPane(animator);        //Display the window.        frame.pack();        frame.setVisible(true);        animator.startAnimation();     }    public static void main(String[] args) {        //Schedule a job for the event-dispatching thread:        //creating and showing this application's GUI.        javax.swing.SwingUtilities.invokeLater(new Runnable() {            public void run() {                createAndShowGUI();            }        });    }}