/*
   创建单选按钮组
*/import java.awt.*;
import java.applet.*;
import java.awt.event.*;public class CheckboxGroups extends Applet {
CheckboxGroup sex;
Checkbox maleSex;
Checkbox femaleSex;

public void init() {                //创建CheckboxGroup
sex=new CheckboxGroup();
maleSex=new Checkbox("男",true,sex);
add(maleSex);
femaleSex=new Checkbox("女",false,sex);
add(femaleSex);
} public void paint(Graphics g) {
//sex.setSelectedCheckbox(femaleSex); //指定单选按钮组中的那个按钮
femaleSex.setState(true);
g.drawString(sex.getSelectedCheckbox().getLabel(), 50, 60 );
}
}

解决方案 »

  1.   

    javax.swing.ButtonGroup bg=new javax.swing.ButtonGroup();//主要是这个
        javax.swing.JRadioButton jrb1=new javax.swing.JRadioButton("radio1");
        javax.swing.JRadioButton jrb2=new javax.swing.JRadioButton("radio1");
        bg.add(jrb1);
        bg.add(jrb2);
      

  2.   

    干嘛用全名呢,这样不好么
    import java.swing.*;
    ...
         ButtonGroup bg=new ButtonGroup();
         JRadioButton jrb1=new JRadioButton("radio1");
         JRadioButton jrb2=new JRadioButton("radio1");
         bg.add(jrb1);
         bg.add(jrb2);
      

  3.   

    /*
     <applet code=TURadioButton width=400 height=300>
     </applet>
     */
    import java.awt.*;
    import javax.swing.*;
    import java.awt.event.*;
    public class TURadioButton extends JApplet
     {
       JRadioButton rButton1,rButton2,rButton3;
       JRadioButton rButton4,rButton5,rButton6;
       JLabel label=null;
       String message=null;
       Font font=null;
       Container container;
       String LF="com.sun.java.swing.plaf.motif.MotifLookAndFeel";
       public void init()
         {
           try
            {
              UIManager.setLookAndFeel(LF);
             }
           catch(Exception e)
             {
               System.out.println("Look and Feel not Initialized!");
             }
           container=this.getContentPane();
           font=new Font("Serif",Font.PLAIN,16);
           message="Check or Uncheck any Radio Button?";
           container.setLayout(new GridLayout(2,1));       rButton1=new JRadioButton("Serif",true);
           CustomListener c1=new CustomListener();
           rButton1.addActionListener(c1);       rButton2=new JRadioButton("SanSerif");
           rButton2.addActionListener(c1);       rButton3=new JRadioButton("Monospaced");
           rButton3.addActionListener(c1);       ButtonGroup group1=new ButtonGroup();
           group1.add(rButton1);
           group1.add(rButton2);
           group1.add(rButton3);       rButton4=new JRadioButton("Plain",true);
           rButton4.addActionListener(c1);       rButton5=new JRadioButton("Bold");
           rButton5.addActionListener(c1);       rButton6=new JRadioButton("Italic");
           rButton6.addActionListener(c1);       ButtonGroup group2=new ButtonGroup();
           group2.add(rButton4);
           group2.add(rButton5);
           group2.add(rButton6);       JPanel panel=new JPanel();
           panel.setLayout(new GridLayout(4,2));
           Icon picture=new ImageIcon("pointer.gif");
           label=new JLabel(message,picture,SwingConstants.CENTER);       panel.add(new JLabel("Font"));
           panel.add(new JLabel("Font Type"));
           panel.add(rButton1);panel.add(rButton4);
           panel.add(rButton2);panel.add(rButton5);
           panel.add(rButton3);panel.add(rButton6);       container.add(panel);
           container.add(label);
         }  class CustomListener implements ActionListener
         {
           public void actionPerformed(ActionEvent evt)
            {
              JRadioButton rButton=(JRadioButton)evt.getSource();
              if(rButton==rButton1)
                {
                  font=new Font("Serif",font.getStyle(),16);
                  label.setFont(font);
                  label.setText("You Selected the SERIF font!");
                  container.validate();
                }          else if(rButton==rButton2)
                {
                  font=new Font("SanSerif",font.getStyle(),16);
                  label.setFont(font);
                  label.setText("You Selected the SANSERIF font!");
                  container.validate();
                }         else if(rButton==rButton3)
                {
                  font=new Font("Monospaced",font.getStyle(),16);
                  label.setFont(font);
                  label.setText("You Selected the MONOSPACED font!");
                  container.validate();
                }        else if(rButton==rButton4)
                {
                  font=new Font(font.getName(),Font.PLAIN,16);
                  label.setFont(font);
                  label.setText("You Selected the PLAIN font!");
                  container.validate();
                }       else if(rButton==rButton5)
                {
                  font=new Font(font.getName(),Font.BOLD,16);
                  label.setFont(font);
                  label.setText("You Selected the BOLD font!");
                  container.validate();
                }      else if(rButton==rButton6)
                {
                  font=new Font(font.getName(),Font.ITALIC,16);
                  label.setFont(font);
                  label.setText("You Selected the ITALIC font!");
                  container.validate();
                }
          }
       }
     }
      

  4.   

    //使用复选框组件-----Checkbox类
    import java.awt.*;
    public class ch16
    {
       public static void main(String args[])
       {
        CheckboxGroup cg=new CheckboxGroup();
        Checkbox C1=new Checkbox();
        Checkbox C2=new Checkbox("王普",true);
        Checkbox C3=new Checkbox("冲姐");
        Checkbox C4=new Checkbox("汉堡");
        Checkbox C5=new Checkbox("薯条",cg,false);
        Checkbox C6=new Checkbox("可乐",cg,false);
        C1.setLabel("王志强");
        C1.setState(true);    //设置复选框的选取状态
        C4.setCheckboxGroup(cg);   //将此复选矿加入群组中
        cg.setSelectedCheckbox(C4);   //设置在群组中的复选框的选取状态    Frame f1=new Frame("使用复选框组件");
        Frame f2=new Frame("使用单选按钮组件");
        f1.setBounds(250,250,250,100);
        f2.setBounds(250,350,250,100);    f1.add(C1,BorderLayout.NORTH);
        f1.add(C2,BorderLayout.CENTER);
        f1.add(C3,BorderLayout.SOUTH);
        f2.add(C4,BorderLayout.NORTH);
        f2.add(C5,BorderLayout.CENTER);
        f2.add(C6,BorderLayout.SOUTH);
        f1.setVisible(true);
        f2.setVisible(true);
       }
    }