手机J2ME程序开发(二)
上一篇文章介绍了一个简单的秒表程序，是使用J2ME提供的StringItem开发的，简单，但是不够美观，下面贴一个使用Canvas编写的秒表程序，就当做一个进阶的例子吧。
package midp.wallimn.com;import java.util.Date;import java.util.Timer;import java.util.TimerTask;import javax.microedition.lcdui.Canvas;import javax.microedition.lcdui.Command;import javax.microedition.lcdui.CommandListener;import javax.microedition.lcdui.Display;import javax.microedition.lcdui.Displayable;import javax.microedition.lcdui.Graphics;import javax.microedition.lcdui.Image;import javax.microedition.lcdui.game.Sprite;import javax.microedition.midlet.MIDlet;import javax.microedition.midlet.MIDletStateChangeException;/** *//** * 秒表程序的高级版本，使用Canvas，外观稍好。 <br/> * * @version : V1.0<br/> * @author : (Email: wallimn@sohu.com QQ: 54871876)<br/> * @date : 2008-1-14 下午01:37:28<br/> */public class StopWatchMIDlet extends MIDlet implements CommandListener ...{ private MyCanvas mainForm; private Timer m_timer;// 定时器 private Display display; private Command EXIT_CMD = new Command("退出", Command.EXIT, 1); private Command STOP_CMD = new Command("停止", Command.STOP, 1); private Command START_CMD = new Command("开始", Command.STOP, 1); private MyTimerTask timerTask; class MyTimerTask extends TimerTask ...{ public int s = 0;// 秒 public int m = 0;// 分 public int h = 0;// 时 public int ms = 0;// 1/100秒 public MyTimerTask() ...{ } public void init() ...{ s = 0; m = 0; h = 0; ms = 0; } public void run() ...{ if (ms == 9) ...{ ms = 0; if (s == 59) ...{ s = 0; if (m == 59) ...{ m = 0; h++; } else ...{ m++; } } else ...{ s++; } } else ...{ ms++; } mainForm.repaint(); } } public StopWatchMIDlet() ...{ display = Display.getDisplay(this); mainForm = new MyCanvas(); mainForm.addCommand(EXIT_CMD);// 添加命令显示 mainForm.addCommand(START_CMD);// 添加命令显示 mainForm.setCommandListener(this);// 添加事件监听 } protected void destroyApp(boolean arg0) ...{ } protected void pauseApp() ...{ } protected void startApp() throws MIDletStateChangeException ...{ display.setCurrent(mainForm); } public void commandAction(Command c, Displayable s) ...{ if (c == EXIT_CMD) ...{ if (m_timer != null) ...{// 停止计时器，释放资源 m_timer.cancel(); m_timer = null; } destroyApp(false); notifyDestroyed(); } else if (c == STOP_CMD) ...{ this.m_timer.cancel(); m_timer = null; mainForm.removeCommand(STOP_CMD); mainForm.addCommand(START_CMD); } else if (c == START_CMD) ...{ // 初始化一个计时器，初始化一个任务 m_timer = new Timer(); timerTask = null;// 先释放旧的任务 timerTask = new MyTimerTask(); timerTask.init(); m_timer.schedule(timerTask, new Date(), 100); mainForm.removeCommand(START_CMD); mainForm.addCommand(STOP_CMD); } } /** *//** * 日历显示输出 <br/> * * @version : V1.0<br/> * @author : wallimn(Email: wallimn@sohu.com QQ: 54871876)<br/> * @date : 2008-1-22 下午04:19:51<br/> */ class MyCanvas extends Canvas ...{ int m_width, m_height; private Image numberImage = null; /** *//** * 数字的宽度 */ private final int numWidth = 11; /** *//** * 数字的高度 */ private final int numHeight = 15; /** *//** * 冒号的宽度 */ private final int colonWidth = 7; private int xPos, yPos; /** *//** * 数字的Y坐标 */ private int numStyle = 15; public MyCanvas() ...{ try ...{ numberImage = Image.createImage("/images/misc.png"); } catch (Exception e) ...{ return; } // 计算数字显示位置，以便使数字居中显示 xPos = (this.getWidth() - numWidth * 9) / 2; yPos = (this.getHeight() - numHeight) / 2; } protected void paint(Graphics g) ...{ g.setColor(0xFFFFFF); g.fillRect(0, 0, this.getWidth(), this.getHeight()); drawMyFlag(g); int h = 0, m = 0, s = 0, ms = 0; if (timerTask != null) ...{ h = timerTask.h; m = timerTask.m; s = timerTask.s; ms = timerTask.ms; } int x = xPos; drawNumber(g, x, yPos, h / 10, numStyle); x += numWidth; drawNumber(g, x, yPos, h % 10, numStyle); x += numWidth; drawNumber(g, x, yPos, 10, numStyle); x += colonWidth; drawNumber(g, x, yPos, m / 10, numStyle); x += numWidth; drawNumber(g, x, yPos, m % 10, numStyle); x += numWidth; drawNumber(g, x, yPos, 10, numStyle); x += colonWidth; drawNumber(g, x, yPos, s / 10, numStyle); x += numWidth; drawNumber(g, x, yPos, s % 10, numStyle); x += numWidth; drawNumber(g, x, yPos, 10, numStyle); x += colonWidth; drawNumber(g, x, yPos, ms, numStyle); } /** *//** * 输出图形格式的数字，这种方式利于数字的多样化 <br/> 编码：wallimn 时间：2008-1-22 下午04:22:55<br/> */ private void drawNumber(Graphics g, int x, int y, int num, int ypos) ...{ int wid = numWidth; if(num==10)wid =colonWidth; g.drawRegion(numberImage, num * numWidth, ypos, wid, numHeight, Sprite.TRANS_NONE, x, y, Graphics.HCENTER | Graphics.VCENTER); } private void drawMyFlag(Graphics g)...{ g.drawRegion(numberImage, 0, 32, 118, 22, Sprite.TRANS_NONE, 0, 0, Graphics.TOP | Graphics.LEFT); } protected void showNotify() ...{ } protected void hideNotify() ...{ } /** *//** * 按钮处理 功能描述： 编码时间：2008-1-22 下午04:23:14 参数及返回值： * * @param kc * @see javax.microedition.lcdui.Canvas#keyPressed(int) */ protected void keyPressed(int kc) ...{ int ga = this.getGameAction(kc); if (ga == Canvas.FIRE || kc == Canvas.KEY_NUM5) ...{ if (numStyle == 0) ...{ numStyle = numHeight; } else if (numStyle == numHeight) ...{ numStyle = 0; } repaint(); } } protected void keyReleased(int arg0) ...{ // 时间: 2008-1-22 上午10:40:00 } }}