example5_5.java

书中的例题

  /* 单选按钮和复选框 */
 import java.awt.*; 
 import java.awt.event.*; 
 import javax.swing.*; 
 class BRDemo extends JFrame 
              implements ItemListener,ActionListener
 { 
   JTextField jtf; 
   BRDemo()
	{ 
     setSize(200,200);
     setVisible(true);
     Container contentPane = getContentPane(); 
     contentPane.setLayout(new FlowLayout()); 
     // 建立图标对象 
     ImageIcon icon1 = new ImageIcon("c1.gif"); 
     ImageIcon icon2 = new ImageIcon("c2.gif"); 
     ImageIcon icon3 = new ImageIcon("c3.gif"); 
     // 在面板上添加复选框 
     JCheckBox cb = new JCheckBox("C", icon1); 
     cb.setRolloverIcon(icon2); 
     cb.setSelectedIcon(icon3); 
     cb.addItemListener(this); 
     contentPane.add(cb); 
     cb = new JCheckBox("C++", icon1); 
     cb.setRolloverIcon(icon2); 
     cb.setSelectedIcon(icon3); 
     cb.addItemListener(this); 
     contentPane.add(cb); 
     cb = new JCheckBox("Java", icon1); 
     cb.setRolloverIcon(icon2); 
     cb.setSelectedIcon(icon3); 
     cb.addItemListener(this); 
     contentPane.add(cb); 
     // 在面板上添加单选按钮 
     JRadioButton b1 = new JRadioButton("鲜花"); 
     b1.addActionListener(this); 
     contentPane.add(b1); 
     JRadioButton b2 = new JRadioButton("鼓掌"); 
     b2.addActionListener(this); 
     contentPane.add(b2); 
     JRadioButton b3 = new JRadioButton("鸡蛋"); 
     b3.addActionListener(this); 
     contentPane.add(b3); 
      // 定义按钮组 
     ButtonGroup bg = new ButtonGroup(); 
     bg.add(b1); 
     bg.add(b2); 
     bg.add(b3); 
     // 在面板上添加文本框 
     jtf = new JTextField(15); 
     contentPane.add(jtf); 
     validate();
     addWindowListener(new WindowAdapter()
       {public void windowClosing(WindowEvent e)
          {System.exit(0);}});
   } 
  public void itemStateChanged(ItemEvent ie)
   { 
      JCheckBox cb = (JCheckBox)ie.getItem(); 
      jtf.setText(cb.getText()); 
   } 
  public void actionPerformed(ActionEvent ae)
   { 
      jtf.setText(ae.getActionCommand()); 
   } 
 }
  //主类
  public class Example5_5
  {
	public static void main(String[] args) 
	 {
		new BRDemo();
	 }
  }