testkeylistener.java

来自「Java语言」· Java 代码 · 共 23 行

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class TestKeyListener extends Applet implements KeyListener{
   Color clr;
   public void init(){
       addKeyListener(this);
       requestFocus();
   }
   public void keyTyped(KeyEvent e){
      if(e.getKeyChar()=='r'||e.getKeyChar()=='R')
         clr=Color.red;
      else if(e.getKeyChar()=='g'||e.getKeyChar()=='G')
         clr=Color.green;
      else if(e.getKeyChar()=='b'||e.getKeyChar()=='B')
         clr=Color.blue;
      else
         clr=null;
      setBackground(clr);
   }
   public void keyReleased(KeyEvent e){}
   public void keyPressed(KeyEvent e){}   
}