hblistenerdemo.java

《java事件处理指南》一书的代码,好东西

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class HBListenerDemo extends JFrame
{
   private JButton button;
   private JTextField jtf;

   public HBListenerDemo()
   {
/*  A JButton is placed on a JFrame.  The button registers   */
/*  a HierarchyBoundsListener.                               */

      button = new JButton("Button");
      button.setBorder(BorderFactory.createRaisedBevelBorder());
      button.addHierarchyBoundsListener(new HierBndsListener());

      jtf = new JTextField(20);
      jtf.setEditable(false);

      JPanel panel = new JPanel();
      panel.add(button);

      getContentPane().add(panel, BorderLayout.CENTER);
      getContentPane().add(jtf, BorderLayout.SOUTH);

      setName("frame");
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setBounds(100, 100, 300, 200);
      setVisible(true);
   }

/*  A HierarchyBoundsListener is implemented as an inner class.       */
/*  If the frame is moved or re-sized, HierarchyEvents generated      */
/*  by the button are sent to either the ancestorResized() or         */
/*  ancestorMoved() methods.  These methods update the text of a      */
/*  JTextField to indicate what has taken place.                      */

   class HierBndsListener implements HierarchyBoundsListener
   {
      public void ancestorResized(HierarchyEvent event)
      {
         Component comp = event.getChanged();
         Dimension d = comp.getSize();
         jtf.setText(comp.getName()+" was resized.  width = "+
                     d.width+" height = "+d.height);
      }

      public void ancestorMoved(HierarchyEvent event) 
      {
         Component comp = event.getChanged();
         jtf.setText(comp.getName()+" was moved to ("+
                     comp.getX()+","+comp.getY()+")");
      }
   }

   public static void main(String args[])
   {
      HBListenerDemo demo = new HBListenerDemo();
   }
}