midletdemo.java~4~

J2ME高级用户界面的学习代码

//MIDletDemo.java

package ORA.ch3;

import java.util.Timer;
import java.util.TimerTask;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class MIDletDemo extends MIDlet
{
  private boolean started = false;
  private Thread thread;
  private int timerInterval;
  private Timer timer;
  private TimerTask task;

  public MIDletDemo()
  {
    System.out.println("Constructor Executed!");
    String interval = getAppProperty("Timer-Interval");
    timerInterval = Integer.parseInt(interval);
    System.out.println("Timer interval is " + interval);
  }

  protected void startApp()throws MIDletStateChangeException
  {
    if(!started)
    {
      started = true;
      System.out.println("startApp called for the first time!");
      startTimer();
    }
    else
    {
      System.out.println("startApp called following pause!");
    }

    synchronized (this)
    {
      if(thread == null)
      {
        thread = new Thread()
        {
          public void run()
          {
            System.out.println("Thread running!");
            while(thread == this)
            {
              try{
                Thread.sleep(1000);
                System.out.println("Thread still alive!");
              }catch(InterruptedException ex){
              }
            }
            System.out.println("Thread terminating!");
          }
        };
      }
    };
    thread.start();
  }

  protected void pauseApp()
  {
    System.out.println("pauseApp called!");
    synchronized (this)
    {
      if(thread != null)
      {
        thread = null;
      }
    }
  }

  protected void destroyedApp()
      throws MIDletStateChangeException
  {
    System.out.println("destroyApp called - unconditional = " + unconditional);
    if(thread != null)
    {
      Thread bgThread = thread;
      thread = null;
      try{
        bgThread.join();
      }catch(InterruptedException ex){
      }
    }
    stopTimer();

  }
}