texteventdemo.java

来自「《java事件处理指南》一书的代码,好东西」· Java 代码 · 共 60 行

import java.awt.*;
import java.awt.event.*;

public class TextEventDemo extends Frame 
{
   private TextField tf1, tf2; 

   public TextEventDemo()
   {
/*  A TextField is created and placed on a Frame.  It registers   */
/*  a TextListener.  A second TextField is used to reflect        */
/*  changes in the text contained by the first TextField.         */

      tf1 = new TextField(25);
      tf1.addTextListener(new TextEventHandler());

      tf2 = new TextField(25);
      tf2.setEditable(false);

      Panel panel = new Panel();
      panel.add(tf1);

      add(panel, BorderLayout.NORTH);
      add(tf2, BorderLayout.SOUTH);

      addWindowListener(new WinAdapter());
      setBounds(100, 100, 300, 200);
      setVisible(true);
   }

/*  The TextListener is implemented as an inner class.  Whenever  */
/*  the text inside the top TextField is changed, a TextEvent is  */
/*  generated and sent to the textValueChanged() method.          */

   class TextEventHandler implements TextListener
   {
      public void textValueChanged(TextEvent event)
      {
         TextField tf = (TextField)event.getSource();
         tf2.setText("Text is: "+tf.getText());
      }
   }

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

/*  This makes sure the application terminates if the window is closed   */

class WinAdapter extends WindowAdapter
{
   public void windowClosing(WindowEvent event) 
   {
      System.exit(0);
   }
}