Android 计时器

计时器的实现常用的三种方法：
方法一：Handler +Thread

public class TimerUtil {
    private final int MSG_TYPE_START = 0;
    private final int MSG_TYPE_PAUSE = 1;
    private final int MSG_TYPE_STOP = 2;
    private int passedTime ;
    private TimeCallBack timeCallBack;

    public TimerUtil() {
        passedTime = 0;
    }

    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case MSG_TYPE_START:
                    handler.postDelayed(recordTime,1000);
                    break;
                case MSG_TYPE_PAUSE:
                    handler.removeMessages(MSG_TYPE_START);
                    break;
                case MSG_TYPE_STOP:
                    passedTime = 0;
                    if (timeCallBack != null){
                        timeCallBack.onTime(passedTime);
                    }
                    handler.removeCallbacks(recordTime);
                    handler.removeMessages(MSG_TYPE_START);
                    break;
            }
        }
    };

    Runnable recordTime = new Runnable() {
        @Override
        public void run() {
           passedTime++;
            if (timeCallBack != null){
                timeCallBack.onTime(passedTime);
            }
            handler.sendEmptyMessage(MSG_TYPE_START);
        }
    };

    public void startCount(){
        handler.sendEmptyMessage(MSG_TYPE_START);
    }
    public void pauseCount(){
        handler.sendEmptyMessage(MSG_TYPE_PAUSE);
    }
    public void stopCount(){
        handler.sendEmptyMessage(MSG_TYPE_STOP);
//        handler.removeCallbacksAndMessages(null);
    }
    public interface TimeCallBack{
        void onTime(int passedTime);
    }
    public void setTimeCallBack(TimeCallBack timeCallBack){
        this.timeCallBack = timeCallBack;
    }

    public void onDestory(){
        handler.removeCallbacksAndMessages(null);
    }
}

方法二：Handler类的postDelyed

public class HanderActivity extends Activity {  
    TextView tvShow;  
    private int i = 0;  
    private int TIME = 1000;  
  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        tvShow = (TextView) findViewById(R.id.tv_show);  
        handler.postDelayed(runnable, TIME); //每隔1s执行  
    }  
  
    Handler handler = new Handler();  
    Runnable runnable = new Runnable() {  
  
        @Override  
        public void run() {  
            // handler自带方法实现定时器  
            try {  
                handler.postDelayed(this, TIME);  
                tvShow.setText(Integer.toString(i++));  
                System.out.println("do...");  
            } catch (Exception e) {  
                // TODO Auto-generated catch block  
                e.printStackTrace();  
                System.out.println("exception...");  
            }  
        }  
    };  
  
}  

方法三：Handler+Timer+TimerTask

public class HanderDemoActivity extends Activity {  
    TextView tvShow;  
    private int i = 0;  
    private int TIME = 1000;  
  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        tvShow = (TextView) findViewById(R.id.tv_show);  
        timer.schedule(task, 1000, 1000); // 1s后执行task,经过1s再次执行  
    }  
  
    Handler handler = new Handler() {  
        public void handleMessage(Message msg) {  
            if (msg.what == 1) {  
                tvShow.setText(Integer.toString(i++));  
            }  
            super.handleMessage(msg);  
        };  
    };  
    Timer timer = new Timer();  
    TimerTask task = new TimerTask() {  
  
        @Override  
        public void run() {  
            // 需要做的事:发送消息  
            Message message = new Message();  
            message.what = 1;  
            handler.sendMessage(message);  
        }  
    };  
}