gaugedemo.java~3~

J2ME高级用户界面的学习代码

//GaugeDemo.java

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class GaugeDemo extends MIDlet implements CommandListener
{
  private Display display;
  private Form form;
  private Command cmdExit = new Command("Exit",Command.SCREEN,1);
  private Gauge gauge;

  public GaugeDemo()
  {
    display = Display.getDisplay(this);
    gauge = new Gauge("Gauge Demo",true,10,3);
    form = new Form("Degree");
    form.append(gauge);
    form.append(new StringItem("Current Degree:"," 3"));
    form.addCommand(cmdExit);
    form.setCommandListener(this);

    ItemStateListener listener = new ItemStateListener()
    {
      public void itemStateChanged(Item item)
      {
        if(item == gauge)
        {
          ((StringItem)form.get(1)).setText(" " + gauge.getValue());
        }
      }
    };
    form.setItemStateListener(listener);
  }

  public void startApp()
  {
    display.setCurrent(form);
  }

  public void pauseApp(){}
  public void destroyApp(boolean unconditional){}
  public void commandAction(Command c,Displayable d)
  {
    if(cmdExit == c)
    {
      destroyApp(false);
      notifyDestroyed();
    }
  }
}