package radio;import java.awt.*;import java.awt.event.*;import java.applet.*;import javax.swing.*;public class che extends Applet {  boolean isStandalone = false;  int nd;  ButtonGroup b1 = new ButtonGroup();  JRadioButton r1 = new JRadioButton();  JRadioButton r2 = new JRadioButton();  JRadioButton r3 = new JRadioButton();  /**Get a parameter value*/  public String getParameter(String key, String def) {    return isStandalone ? System.getProperty(key, def) :      (getParameter(key) != null ? getParameter(key) : def);  }  /**Construct the applet*/  public che() {  }  /**Initialize the applet*/  public void init() {    try {      jbInit();    }    catch(Exception e) {      e.printStackTrace();    }  }  /**Component initialization*/  private void jbInit() throws Exception {    r1.setText("圓形");    r1.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        r1_actionPerformed(e);      }    });    r2.setText("正方形");    r2.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        r2_actionPerformed(e);      }    });    r3.setText("扇形");    r3.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        r3_actionPerformed(e);      }    });    this.add(r1, null);    this.add(r2, null);    this.add(r3, null);    b1.add(r1);    b1.add(r2);    b1.add(r3);  }  /**Get Applet information*/  public String getAppletInfo() {    return "Applet Information";  }  /**Get parameter info*/  public String[][] getParameterInfo() {    return null;  }  void r1_actionPerformed(ActionEvent e) {     clear();     draw(1);  }  void r2_actionPerformed(ActionEvent e) {     clear();     draw(2);  }  void r3_actionPerformed(ActionEvent e) {     clear();     draw(3);  }  public void clear(){     g.clearRect(20,20,280,280);  }  public void draw(int n){    nd=n;    repaint();  }  public void paint(Graphics g){    switch(nd){        case 1:          g.drawOval(60,60,30,30);          break;        case 2:          g.drawRect(120,60,30,30);          break;        case 3:          g.drawArc(180,60,30,30,0,130);          break;     }  }  public void update(Graphics g){     paint(g);  }}