图片浏览小程序(java+applet)的设计

import java.awt.*; import java.applet.*; import java.awt.event.*; public class Pic_show extends Applet implements ActionListener { Button pic_first,pic_next,pic_forword,pic_last,pic_goto,pic_fangda,pic_suoxiao, mid_play,mid_loop,mid_stop; static int number=10; static int count=0; static int pan; Label yeshu; AudioClip clip; TextField text1; static Image[] card=new Image[number]; Mycanvas canvas; static String str=String.valueOf(count); public void init() { setLayout(new BorderLayout()); FlowLayout flow=new FlowLayout(); flow.setAlignment(FlowLayout.CENTER); clip=getAudioClip(getCodeBase(),"mytest.mid"); text1=new TextField("1",2); Panel p1=new Panel(); Panel p2=new Panel(); p1.setLayout(flow); p2.setLayout(flow); pic_first=new Button("第一张"); pic_forword=new Button("上一张"); pic_next=new Button("下一张"); pic_last=new Button("最后一张"); pic_goto=new Button("转到"); pic_fangda=new Button("放大"); pic_suoxiao=new Button("缩小"); mid_play=new Button("开始播放"); mid_loop=new Button("循环播放"); mid_stop=new Button("停止播放"); canvas=new Mycanvas(); add(p2,BorderLayout.SOUTH); add(canvas,BorderLayout.CENTER); add(p1,BorderLayout.NORTH); String bbb=String.valueOf(number); yeshu=new Label("1"); p1.add(yeshu); p1.add(new Label("/")); p1.add(new Label(bbb)); p1.add(pic_first); p1.add(pic_forword); p1.add(pic_next); p1.add(pic_last); p1.add(text1); p1.add(pic_goto); p1.add(pic_fangda); p1.add(pic_suoxiao); p2.add(mid_play); p2.add(mid_loop); p2.add(mid_stop); pic_first.addActionListener(this); pic_forword.addActionListener(this); pic_next.addActionListener(this); pic_last.addActionListener(this); pic_goto.addActionListener(this); pic_fangda.addActionListener(this); pic_suoxiao.addActionListener(this); mid_play.addActionListener(this); mid_loop.addActionListener(this); mid_stop.addActionListener(this); for(int i=0;i<number;i++) { card[i]=getImage(getCodeBase(),"a"+(i+1)+".gif"); } } public void stop() {clip.stop();} public void actionPerformed(ActionEvent e) { if(e.getSource()==pic_first) { pan=0; count=0; yeshu.setText(String.valueOf(count+1)); text1.setText(String.valueOf(count+1)); pic_forword.setEnabled(false); canvas.repaint(); pic_next.setEnabled(true); } else if(e.getSource()==pic_forword) { pan=0; if(count<=0) {pic_forword.setEnabled(false);} else {count--; yeshu.setText(String.valueOf(count+1)); text1.setText(String.valueOf(count+1)); canvas.repaint(); pic_next.setEnabled(true);} } else if(e.getSource()==pic_next) { pan=0; if (count>=number-1) {pic_next.setEnabled(false);} else {count++; yeshu.setText(String.valueOf(count+1)); text1.setText(String.valueOf(count+1)); canvas.repaint(); pic_forword.setEnabled(true); } } else if(e.getSource()==pic_last) { pan=0; count = number-1; pic_next.setEnabled(false); canvas.repaint(); pic_forword.setEnabled(true); yeshu.setText(String.valueOf(count+1)); text1.setText(String.valueOf(count+1)); } else if(e.getSource()==pic_goto||e.getSource()==text1) { pan=0; int num=0; try {num=Integer.parseInt(text1.getText());} catch(NumberFormatException event) {text1.setText("张数");} count=num-1; yeshu.setText(String.valueOf(count+1)); canvas.repaint(); } else if(e.getSource()==pic_fangda) { pan=1; canvas.repaint(); } else if(e.getSource()==pic_suoxiao) { pan=2; canvas.repaint(); } else if(e.getSource()==mid_play) { clip.play(); } else if(e.getSource()==mid_loop) { clip.loop(); } if(e.getSource()==mid_stop) { clip.stop(); } } } class Mycanvas extends Canvas { float width, height, pWidth, pHeight,bi; public void paint(Graphics g) { if((Pic_show.card[Pic_show.count])!=null) { if(Pic_show.pan==0) { width = Pic_show.card[Pic_show.count].getWidth(this); height = Pic_show.card[Pic_show.count].getHeight(this); pWidth = getSize().width-20; pHeight = getSize().height-20; if(width>=pWidth || height>=pHeight) { float x = height/width; if(x >= 0.75) { width = width*pHeight/height; height = pHeight; } else { height = height*pWidth/width; width = pWidth; } } g.drawImage(Pic_show.card[Pic_show.count], (int)(pWidth-width+20)/2, 10, (int)width, (int)height, this);} else if(Pic_show.pan==1) { bi=width/height; height=(int)(width*1.1/bi); width=(int)(width*1.1); g.drawImage(Pic_show.card[Pic_show.count], (int)(pWidth-width+20)/2, 10, (int)width, (int)height, this); } else if(Pic_show.pan==2) { bi=width/height; height=(int)(width*0.9/bi); width=(int)(width*0.9); g.drawImage(Pic_show.card[Pic_show.count], (int)(pWidth-width+20)/2, 10, (int)width, (int)height, this); } } } }