public class ClockActivity extends Activity {
    private TextView tvClock;
    public static final String CLOCK_ACTION="com.jereh.Clock_Action";
    public static  int TIME=2*60*60*1000;//倒計時2個小時
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_clock);
        tvClock
 
=(TextView)super.findViewById(R.id.tvClock);
        regReceiver();//註冊廣播
        startService(new Intent(this,ClockService.class));//啟動計時服務
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        super.unregisterReceiver(clockReceiver);
        TIME=2*60*60*1000;
        Intent intent
 
=new Intent();
        intent.setAction(ClockService.CLOCK_SERVICE_ACTION);
        intent.putExtra("method", "stop");
        super.sendBroadcast(intent);
    }
    private void regReceiver(){
        IntentFilter intentFilter=new IntentFilter();
        intentFilter.addAction(CLOCK_ACTION);
        
 
super.registerReceiver(clockReceiver, intentFilter);
    }
    /**
    *廣播接受者，接受來自ClockService（計時服務）的廣播，ClockService每隔一秒
*鍾發一次廣播
    */    
    private BroadcastReceiver clockReceiver=new BroadcastReceiver(){
        @Override
        public void onReceive(Context context, Intent intent) {
            changeTime();//改變TextView中的顯示時間
        }
    };
    //通過傳送廣播，控制計時服務
    //繼續計時
    public void restart(View view){
        Intent intent=new Intent();
        intent.setAction(ClockService.CLOCK_SERVICE_ACTION);
        intent.putExtra("method", "continue");
        super.sendBroadcast(intent);
    }
    //通過傳送廣播，控制計時服務
    //暫停計時
    public void pause(View view){
        Intent intent=new Intent();
        intent.setAction(ClockService.CLOCK_SERVICE_ACTION);
        intent.putExtra("method","pause");
        super.sendBroadcast(intent);
    }
    private void changeTime(){
        String stime="";
        if(TIME==0){
            stime="計時結束";
        }else{
                int hour=TIME/(1000*60*60);
                int minute=TIME%(1000*60*60)/(60*1000);
                int second=(TIME%(1000*60*60))%(60*1000)/1000;
                String shour=""+hour,sminute=""+minute,ssecond=""+second;
                if(hour<=9){
                    shour="0"+hour;
                }
                if(minute<=9){
                    sminute="0"+minute;
                }
                if (second<=9){
                    ssecond="0"+second;
                }
                stime=shour+":"+sminute+":"+ssecond;
        }
        tvClock.setText(stime);
    }

}