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
  }
 }

}

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作者：wallimn　电邮：wallimn@sohu.com　时间：2008-02-13
博客：http://blog.csdn.net/wallimn　http://wallimn.iteye.com
网络硬盘：http://wallimn.ys168.com
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