一、进度条类   Gauge控件就是一个进度条，通过图形的方式表达一个程序运行的进度或其它操作的运行过程，Gauge的构造函数如下：
Gauge(String label,boolean interactive,int maxValue,int initialValue)   其中，参数"label"指定了控件的标题，参数"interactive"指定了控件的类型，如果设置为true,则表示为交互类型（用于音量控制等），如设置为false,则为不交互类型，只能通过程序控制进度条。参数"maxValue"指定了进度条的最大值，参数initialValue指定了进度条的初始值。import javax.microedition.lcdui.*;
public class GaugeThread extends Gauge  implements Runnable {
 private int maxValue = 10;
   private int add = 1;
   private boolean done = false;  
   
    public GaugeThread(String label, int maxValue,
           int initialValue) {
        super(label, false, maxValue, initialValue);
        this.maxValue = maxValue;
        new Thread(this).start();
    }
    public void run() {
        while (!done) {
            int newValue = getValue() + add;
            if (newValue == maxValue) {
                add = -1;
            } else if (newValue == 0) {
                add = 1;
            }
            setValue(newValue);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException err) {
            }
        }
    }
   
    void setDone() {
        done = true;
    }
}

 
  二、主程序
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class gaugeDemo_2 extends MIDlet implements CommandListener {
 private Command exitCommand;
 private Form mainform;
 private GaugeThread gthread;
 public gaugeDemo_2() {
  exitCommand = new Command("Exit", Command.EXIT, 1);
  mainform = new Form("gauge实例");
  mainform.addCommand(exitCommand);
  mainform.setCommandListener(this);
  gthread = new GaugeThread("后台自动增加",40,0);
  //new Thread(gthread).start();
  
  mainform.append(gthread);
  mainform.get(0).setLayout(Item.LAYOUT_EXPAND|Item.LAYOUT_NEWLINE_AFTER);
 }
 protected void startApp() throws MIDletStateChangeException {
  Display.getDisplay(this).setCurrent(mainform);
 }
 protected void pauseApp() {
 }
 protected void destroyApp(boolean p1) {
  gthread.setDone();
 }
 public void commandAction(Command c, Displayable d) {
  if (c == exitCommand) {
   destroyApp(false);
   notifyDestroyed();
  }
 }