倒计时器，三秒触发消息，接收到键值操作，重新倒计时开始。

  直接上一个计时器线程类，见代码。
package com.cultraview.ctvmenu.ui;
import android.os.Handler;
import android.util.Log;
public class SelectedTimer implements Runnable {
    public final static int SELECTED_SUCCESS_MSG = 102;
    private static Handler handler;
    public static boolean enableMenu = false;
    private static boolean isStopSelected = false;
    private static boolean isStop = true;
    private static SelectedTimer instance;

    public static void resetSelect() {
        isStopSelected = true;
    }
    public static void resumeSelect() {
        if (isStop) {
            isStop = false;
            Log.d("yql", " 2 new Thread");
            new Thread(instance).start();
        }
    }
    public static void pauseSelect() {
        isStop = true;
    }
    private SelectedTimer() {
        isStop = true;
    }
    public void start() {
        if (isStop) {
            isStop = false;
            Log.d("yql", "3 new Thread");
            new Thread(this).start();
        }
        isStopSelected = false;
    }
    public static SelectedTimer getInstance() {
        if (instance == null) {
            instance = new SelectedTimer();
        }
        return instance;
    }
    public static void setHandler(Handler hndler) {
        handler = hndler;
    }
    public static void CloseSelect() {
        if (handler != null)
            handler.sendEmptyMessage(SELECTED_SUCCESS_MSG);
    }
    @Override
    public void run() {
        while (!isStop) {
            isStopSelected = false;
            try {
                Thread.currentThread();
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            Log.d("yql","isStopSelected ="+isStopSelected);
            if(!isStopSelected){
                if (handler != null)
                    Log.d("yql","TIME_OUT_MSG");
                  handler.sendEmptyMessage(SELECTED_SUCCESS_MSG);
            }
        }
    }
}
调用的时候在Activity类中加这这几个接口代码：
    protected void onResume() {
        // TODO Auto-generated method stub
       
        SelectedTimer.resumeSelect();
        
        super.onResume();
    }

    @Override
    public void onUserInteraction() {
        // TODO Auto-generated method stub
        
        SelectedTimer.resetSelect();
        super.onUserInteraction();
    }

    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        
        SelectedTimer.pauseSelect();
        super.onPause();
    }
其中起关键作用的是onUserInteraction()，这个接口是当有按键触发时，或者其他动作操作的时候初始化时会调用一次，所以这个接口可以做到重置计时器的功能，就是一旦按键函数起作用，那么计时器重新开始倒计时。
另外需要注意的是，使用上述倒计时的类需要在引用类Activity中先初始化，及在onCreate中加入：
SelectedTimer.getInstance();
SelectedTimer.setHandler(handler);

方便好用的倒计时类，你值得拥有。