import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.event.*;/** * <p>Title: 滑動桿演示</p> * <p>Description: 使用滑動桿控制定時器，來控制圖片的播放速度</p> * <p>Copyright: Copyright (c) 2003</p> * <p>Filename: SliderDemo.java</p> * @author 杜江 * @version 1.0 */public class SliderDemo extends JPanel                        implements ActionListener,                                   WindowListener,                                   ChangeListener {    //設(shè)置圖片的參數(shù)    static final int FPS_MIN = 0; //設(shè)置最小值    static final int FPS_MAX = 30; //設(shè)置最大值    static final int FPS_INIT = 15;  //初始數(shù)值    int frameNumber = 0;    int NUM_FRAMES = 14;    ImageIcon[] images = new ImageIcon[NUM_FRAMES];    int delay;    Timer timer;    boolean frozen = false;    //這個標(biāo)簽用來顯示這只小狗    JLabel picture;    public SliderDemo() {        setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));        delay = 1000 / FPS_INIT;        //信息提示標(biāo)簽        JLabel sliderLabel = new JLabel("調(diào)整滑動桿，改變播放速度！", JLabel.CENTER);        sliderLabel.setAlignmentX(Component.CENTER_ALIGNMENT);        //創(chuàng)建一個滑動桿，定義了最小值和最大值以及初始值        JSlider framesPerSecond = new JSlider(JSlider.HORIZONTAL,                                              FPS_MIN, FPS_MAX, FPS_INIT);        framesPerSecond.addChangeListener(this);        //定義滑動桿參數(shù)        framesPerSecond.setMajorTickSpacing(10);//每10刻度標(biāo)注一次        framesPerSecond.setMinorTickSpacing(1);//最小刻度為1        framesPerSecond.setPaintTicks(true);//繪制滑動桿上的刻度        framesPerSecond.setPaintLabels(true);//在滑動過程中繪制滑動塊        framesPerSecond.setBorder(                BorderFactory.createEmptyBorder(0,0,10,0));        //定義一個用來顯示圖片的標(biāo)簽        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); //顯示第一張圖        //將成員添加到面板上        add(sliderLabel);        add(framesPerSecond);        add(picture);        setBorder(BorderFactory.createEmptyBorder(10,10,10,10));        //設(shè)置一個定時器來觸發(fā)這個事件        timer = new Timer(delay, this);        timer.setInitialDelay(delay * 7); //在每輪循環(huán)停頓時間        timer.setCoalesce(true);//設(shè)置重復(fù)循環(huán)    }/** *<br>方法說明：添加一個窗體監(jiān)聽 *<br>輸入?yún)?shù)： *<br>返回類型： */    void addWindowListener(Window w) {        w.addWindowListener(this);    }    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) {}/** *<br>方法說明：對滑動桿進(jìn)行監(jiān)聽 *<br>輸入?yún)?shù)：ChangeEvent e 滑動桿變動事件 *<br>返回類型： */    public void stateChanged(ChangeEvent e) {        JSlider source = (JSlider)e.getSource();        if (!source.getValueIsAdjusting()) {            int fps = (int)source.getValue();//獲得滑動桿的值            if (fps == 0) {                if (!frozen) stopAnimation();            } else {                delay = 1000 / fps;                timer.setDelay(delay);                timer.setInitialDelay(delay * 10);                if (frozen) startAnimation();            }        }    }/** *<br>方法說明：開始動畫 *<br>輸入?yún)?shù)： *<br>返回類型： */    public void startAnimation() {        timer.start();        frozen = false;    }/** *<br>方法說明：停止動畫 *<br>輸入?yún)?shù)： *<br>返回類型： */    public void stopAnimation() {        timer.stop();        frozen = true;    }/** *<br>方法說明：事件監(jiān)聽 *<br>輸入?yún)?shù)： *<br>返回類型： */    public void actionPerformed(ActionEvent e) {        //改變圖片幀        if (frameNumber == (NUM_FRAMES - 1)) {            frameNumber = 0;        } else {            frameNumber++;        }        updatePicture(frameNumber); //顯示下張圖        if ( frameNumber==(NUM_FRAMES - 1)          || frameNumber==(NUM_FRAMES/2 - 1) ) {            timer.restart();        }    }/** *<br>方法說明：繪制當(dāng)前幀 *<br>輸入?yún)?shù)：int frameNum 圖片幀數(shù)數(shù) *<br>返回類型： */    protected void updatePicture(int frameNum) {        if (images[frameNumber] == null) {            images[frameNumber] = createImageIcon("images/doggy/T"                                                  + frameNumber                                                  + ".gif");        }        //繪制圖片        if (images[frameNumber] != null) {            picture.setIcon(images[frameNumber]);        } else { //如果沒有發(fā)現(xiàn)圖片            picture.setText("image #" + frameNumber + " not found");        }    }/** *<br>方法說明：獲取圖片 *<br>輸入?yún)?shù)：String path 圖片路徑 *<br>返回類型：ImageIcon 圖片對象 */    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;        }    }/** *<br>方法說明：主方法 *<br>輸入?yún)?shù)： *<br>返回類型： */    public static void main(String[] args) {        JFrame.setDefaultLookAndFeelDecorated(true);        //定義窗體        JFrame frame = new JFrame("SliderDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //實例化本類        SliderDemo animator = new SliderDemo();        animator.setOpaque(true);        frame.setContentPane(animator);        //顯示窗體        frame.pack();        frame.setVisible(true);        animator.startAnimation();     }}