anceventdemo.java

《java事件处理指南》一书的代码,好东西

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

public class AncEventDemo extends JFrame implements AncestorListener
{
   private JButton button; 
   private JTextField jtf;

   public AncEventDemo()
   {
/*   A JButton is created and placed on a JFrame.  The JButton         */
/*   registers an AncestorListener.  Because the AncEventDemo          */
/*   class serves as the AncestorListener, the addAncestorListener()   */
/*   method is passed the "this" reference.                            */

      button = new JButton("help");
      button.setBorder(BorderFactory.createRaisedBevelBorder());
      button.addAncestorListener(this);

      jtf = new JTextField(15);
      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);
   }

/*  The AncEventDemo class serves as the AncestorListener so the     */
/*  implementations of the methods declared in the AncestorListener  */
/*  interface are provided inside the AncEventDemo class. If the     */
/*  JFrame is moved, the JButton generates an AncestorEvent which    */
/*  is sent to the ancestorMoved() method.                           */

   public void ancestorMoved(AncestorEvent event)
   {
      Container ancestor = event.getAncestor();
	  String framename=ancestor.getName();
	  try{
      if (framename.equals("frame") )
      {
         jtf.setText("frame was moved to ("+ancestor.getX()+","+
                      ancestor.getY()+")");
      }
	  }catch(Exception e){}
   }

   public void ancestorAdded(AncestorEvent event) {}
   public void ancestorRemoved(AncestorEvent event){}

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