keyeventsdemo.java

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/*
 * $Header$
 * $Date$ 
 * $Revision$
 * Copyright (C) 2003-2004 CIC, Tsinghua Univ. 
 */
package jcase.gui;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

/**
 * KeyEventsDemo 
 */
public class KeyEventsDemo extends BaseDemo implements KeyListener{
	String msg;
	int x,y;
	
	/**
	 * @see jcase.gui.BaseDemo#init()
	 */
	protected void init() {
		x=20;
		y=20;
		msg="You input: ";
		addKeyListener(this);
		requestFocus(); // request input focus
	}
	/**
	 * @see jcase.gui.BaseDemo#getTitle()
	 */
	public String getTitle() {
		
		return "键盘事件处理示例";
	}
	
	
	public void paint(Graphics g) {
		g.drawString(msg,x,y);
	}
	/**
	 * @see java.awt.event.KeyListener#keyTyped(java.awt.event.KeyEvent)
	 */
	public void keyTyped(KeyEvent e) {
		msg+=e.getKeyChar();
		repaint();
	}
	/**
	 * @see java.awt.event.KeyListener#keyPressed(java.awt.event.KeyEvent)
	 */
	public void keyPressed(KeyEvent e) {
		int key = e.getKeyCode();
		switch (key) {

			case KeyEvent.VK_F1:
				msg += "<F1>";
				break;

			case KeyEvent.VK_F2:
				msg += "<F2>";

				break;
			case KeyEvent.VK_F3:
				msg += "<F3>";
				break;

			case KeyEvent.VK_PAGE_DOWN:
				msg += "<PgDn>";
				break;
			case KeyEvent.VK_PAGE_UP:
				msg += "<PgUp>";
				break;
			case KeyEvent.VK_LEFT:
				msg += "<Left Arrow>";
				break;

			case KeyEvent.VK_RIGHT:
				msg += "<Right Arrow>";
				break;
			case KeyEvent.VK_BACK_SPACE: //如果是退格键，清空缓冲区内容
				msg ="You input: ";
				break;
		}
		repaint();
	}
	/**
	 * @see java.awt.event.KeyListener#keyReleased(java.awt.event.KeyEvent)
	 */
	public void keyReleased(KeyEvent e) {
		// TODO something else
		System.out.println(e);
	}
	public Dimension getPreferredSize() {
		return new Dimension(400,100);
	}
}