keyeventdemo.java

来自「《java事件处理指南》一书的代码,好东西」· Java 代码 · 共 48 行

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

public class KeyEventDemo extends JFrame 
{
   public KeyEventDemo()
   {
/*  An empty JFrame is created and registers a KeyListener  */

      addKeyListener(new KeyEventHandler());
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setBounds(100, 100, 300, 200);
      setVisible(true);
   }

/*  The KeyListener is implemented as an inner class that extends  */
/*  the KeyAdapter class.  When the JFrame has keyboard focus and  */
/*  a key is typed, a KeyEvent is generated and sent to the        */
/*  keyTyped() method.  If a 'b' is typed, the JFrame is resized   */
/*  bigger.  If a 's' is typed, the JFrame is resized smaller.     */
/*  If a 'q' is typed, the application quits.                      */

   class KeyEventHandler extends KeyAdapter
   {
      public void keyTyped(KeyEvent event)
      {
         if ( event.getKeyChar() == 'b' )
         {
            setSize( (int)(getWidth()*1.1), (int)(getHeight()*1.1) );
         }
         if ( event.getKeyChar() == 's' )
         {
            setSize( (int)(getWidth()*0.9), (int)(getHeight()*0.9) );
         }
         if ( event.getKeyChar() == 'q' )
         {
            System.exit(0);
         }
      }
   }

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