java代码：

Timer timer = new Timer( ); 

TimerTask task = new TimerTask( ) {
 public void run ( ) {
 Message message = new Message( );
 message.what = 1;
 handler.sendMessage(message);
 }
 };final Handler handler = new Handler( ) {
 public void handleMessage(Message msg) {
 switch (msg.what) {
 case 1:
 log.e("Timer","Timer");
 update( );
 break;
 }super.handleMessage(msg);
 }
 };protected void onDestroy ( ) {
 if (timer != null) {
 timer.cancel( );
 timer = null;
 }
 super.onDestroy( );
 }
 protected void onCreate (Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 this.setContentView(R.layout.main);
 timer.schedule(task,1000,5000);
 }

        最重要的一点是 timer.schedule(task,1000,5000),如果设置为 timer.schedule(task,5000)是不会工作的。

        因为timer.schedule(task,5000) 是表示执行一次的任务。
        timer.schedule(task,1000,5000)表示 1 秒钟后开始 5 秒钟为周期 重复执行，
        更好的方法是通过下面的代码 (Handler加Runnable线程，更简洁）

java代码：

private Handler handler = new Handler( );
private Runnable runnable = new Runnable( ) {
 public void run ( ) {
 update( );handler.postDelayed(this,1000); 
 //postDelayed(this,1000)方法安排一个Runnable对象到主线程队列中
 }
 };handler.postDelayed(runnable,1000); // 开始Timer
 handler.removeCallbacks(runnable); //停止Timer