使用Java编写浏览图片和播放音乐的程序

本文介绍了Java中浏览图片和播放音乐的实现方法。

/**
 *程序要求:编写一个Applet的小程序，准备5幅图片和三个音乐文件，绘制到Applet中，
 *并增加几个按钮，控制图片的切换、放大、缩小和音乐文件的播放。
 *作者：wwj
 *日期：2012/4/29
 *参考：neicole
 *功能：能进行图片和歌曲的选择变换的applet小程序
 **/

 import javax.swing.*;
 import java.awt.*;
 import java.awt.event.*;
 import java.applet.Applet;
 import java.applet.AudioClip;

 public class Ex7_2 extends Applet implements ActionListener,ItemListener
 {

  //创建两个面板
  JPanel p1=new JPanel();
  JPanel p2=new JPanel();
  JPanel p3=new JPanel();
  //声音对象
  AudioClip[] sound=new AudioClip[3];
  int playingSong=0;
  //切换图片的按钮
  JButton lastPic=new JButton("上一张");
  JButton setLarge=new JButton("放大");
  JButton setLittle=new JButton("缩小");
  JButton nextPic=new JButton("下一张");
  //切换歌曲的按钮
  JButton lastSound=new JButton("上一首");
  JButton play=new JButton("播放");
  JButton loop=new JButton("连续");
  JButton stop=new JButton("停止");
  JButton nextSound=new JButton("下一首");
  //曲目下拉列表
  JComboBox xx;
  String names[]={ "曲目1.wav","曲目2.wav","曲目3.wav"};
 
 //创建画布对象
 MyCanvasl showPhotos;

  public void init()
  {
   //窗口布局
   this.setLayout(new BorderLayout());

   //为图片控制按钮注册监听器
   lastPic.addActionListener(this);
   setLarge.addActionListener(this);
   setLittle.addActionListener(this);
   nextPic.addActionListener(this);

   //向面板p1添加组件
   p1.add(lastPic);
   p1.add(setLarge);
   p1.add(setLittle);
   p1.add(nextPic);
   p1.repaint();
 
  //实例化下拉列表对象
  xx = new JComboBox(names);
  xx.addItemListener(this);

     //为控制播放音乐按钮注册监听器
  lastSound.addActionListener(this);
  play.addActionListener(this);
  loop.addActionListener(this);
  stop.addActionListener(this);
  nextSound.addActionListener(this);

  for(int i=0;i<3;i++)
   {
   sound[i]=getAudioClip(getCodeBase(),"music/"+"曲目"
     +Integer.toString(i+1)+".wav");
   }
  

  
     //向面板p2添加组件
   p2.add(xx);
   p2.add(lastSound);
   p2.add(play);
   p2.add(loop);
   p2.add(stop);
   p2.add(nextSound);
   p2.repaint();
  
  showPhotos = new MyCanvasl();
  p3.add(showPhotos);
   p3.repaint();

  //把面板p1和p2分别布置到窗口的北部和南部
   add(p1,BorderLayout.NORTH);
   add(p2,BorderLayout.SOUTH);
   add(p3,BorderLayout.CENTER);

   this.repaint();

  }

  //按钮的事件处理
  public void actionPerformed(ActionEvent e)
  {

  
  if(e.getSource() == lastPic){
   showPhotos.changePhotoShow('P');
  }
  else if(e.getSource() == nextPic){
   showPhotos.changePhotoShow('N');
  }
  else if(e.getSource() == setLarge){
   showPhotos.changePhotoSize('B');
  }
  else if(e.getSource() == setLittle){
   showPhotos.changePhotoSize('S');
  }
 
  else if(e.getSource()==lastSound){ //上一首
   sound[playingSong].stop();
   playingSong=(playingSong-1+3)%3;
   xx.setSelectedIndex(playingSong);
   sound[playingSong].play();

  }
  else if(e.getSource()==play){  //按下播放按钮
   sound[playingSong].play();
  }
  else if(e.getSource()==loop){  //按下循环按钮
   sound[playingSong].loop();
  }
  else if(e.getSource()==stop){  //按下停止按钮
   sound[playingSong].stop();
  }
  else{        //下一首
   sound[playingSong].stop();
   playingSong=(playingSong+1)%3;
   xx.setSelectedIndex(playingSong);
   sound[playingSong].play();

  } 
  }

  //下拉列表的事件处理
  public void itemStateChanged(ItemEvent e)
  {
  
   sound[playingSong].stop();
   sound[playingSong]=getAudioClip(getCodeBase(),"music/"+xx.getSelectedItem());
  }

 class MyCanvasl extends Canvas
 {
  
  public Image[] img=new Image[5];

  int MaxWidth = 600;
  int MaxHeight = 500;
  int nowImageIndex = 0;
  int coordinateX = 0;
  int coordinateY = 0;
  int currentWidth = MaxWidth;
  int currentHeight = MaxHeight;

  
  MyCanvasl(){
   setSize(MaxWidth,MaxHeight);
   //获取当前目录下的图片
   for(int i=0;i<5;i++){
    img[i]=getImage(getCodeBase(),"image/"+Integer.toString(i+1)+".jpg");
   }
  }

  private void changePhotoIndex(int index){
   nowImageIndex = index;
   changePhotoSize('M');
  }

  public void changePhotoShow(char command){
   if('P' == command){
    changePhotoIndex((nowImageIndex + 5 - 1 ) % 5);
   }
   else if('N' == command){
    changePhotoIndex((nowImageIndex + 1) % 5);
   }
  }
  

   public void changePhotoSize(char command){
   if ('M' == command){
    currentWidth = MaxWidth;
    currentHeight = MaxHeight;
   }
   else if ('B' == command){
    if(MaxWidth >= (currentWidth + 100) && MaxHeight >= (currentHeight + 100)){
     currentWidth += 100;
     currentHeight += 100;
    }
   }
   else if('S' == command){
    if((0 < (currentWidth - 100)) && (0 < (currentHeight - 100))){
     currentWidth = currentWidth - 100;
     currentHeight = currentHeight - 100;
    }
   }
   coordinateX = (MaxWidth - currentWidth) / 2;
   coordinateY = (MaxHeight - currentHeight) / 2;
   repaint();
  }
   //paint方法用来在窗口显示图片
  public void paint(Graphics g){
        g.drawImage(img[nowImageIndex],coordinateX,coordinateY,currentWidth,currentHeight,this);

  }
 }
 }

 最终效果如下图所示：