Java图形设计和多媒体基础

ITJS的这篇文章主要介绍了Java的图形设计以及多媒体处理，源码作者也做了详细的注释，对于初学者应该不难。详细请看下文。

同心圆效果图：

/**  
 *程序要求：新建一个600*600像素的应用程序窗口，并在窗口中绘制5个不同颜色的同心圆，  
 *所有圆心都是屏幕的中心点，相邻两个圆直接的半径相差50像素  
 *效果图如下图所示（颜色随机设置），源程序保存为Ex7_1.java。  
 *作者：wwj  
 *日期：2012/4/25  
 *功能：显示一个有5个不同颜色的同心圆  
 **/ 

 import javax.swing.*;  
 import java.awt.*;  
 import java.awt.Color;  
 public class Ex7_1 extends JFrame  
 {  
     int red,green,blue;  
     Color color;  

     public Ex7_1()  
     {  
         super("一个有5个不同颜色的同心圆");    //显示窗口名称  
         setSize(600,600);                      //设置窗口大小  
         setVisible(true);                      //设置为可见  
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置窗口关闭动作  

     }  

     public void paint(Graphics g)  
     {  
         //第一个圆  
        red=(int)(Math.random()*255);  
        green=(int)(Math.random()*255);  
        blue=(int)(Math.random()*255);  
        color=new Color(red,green,blue);  
        g.setColor(color);  
        g.fillOval(175,175,250,250);  
        //第二个圆  
        red=(int)(Math.random()*255);  
        green=(int)(Math.random()*255);  
        blue=(int)(Math.random()*255);  
        color=new Color(red,green,blue);  
        g.setColor(color);  
        g.fillOval(200,200,200,200);  
        //第三个圆  
        red=(int)(Math.random()*255);  
        green=(int)(Math.random()*255);  
        blue=(int)(Math.random()*255);  
        color=new Color(red,green,blue);  
        g.setColor(color);  
        g.fillOval(225,225,150,150);  
        //第四个圆  
        red=(int)(Math.random()*255);  
        green=(int)(Math.random()*255);  
        blue=(int)(Math.random()*255);  
        color=new Color(red,green,blue);  
        g.setColor(color);  
        g.fillOval(250,250,100,100);  
        //第五个圆  
        red=(int)(Math.random()*255);  
        green=(int)(Math.random()*255);  
        blue=(int)(Math.random()*255);  
        color=new Color(red,green,blue);  
        g.setColor(color);  
        g.fillOval(275,275,50,50);  

     }         

     public static void main(String[] args)  
     {  
         Ex7_1 e = new Ex7_1();       
     }  

 }

播放音乐和切换图片的小程序效果图：

/**  
 *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);  

     }  
    }  
 }