如何从14:45到16:15运行计时器

Question

我需要从14:45到16:15运行timer。

这是我的代码：

public class MainActivity extends Activity {

    CheckBox optSingleShot;
    Button btnStart, btnCancel;
    TextView textCounter;

    Timer timer;
    MyTimerTask myTimerTask;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        optSingleShot = (CheckBox)findViewById(R.id.singleshot);
        btnStart = (Button)findViewById(R.id.start);
        btnCancel = (Button)findViewById(R.id.cancel);
        textCounter = (TextView)findViewById(R.id.counter);

        btnStart.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {

                if(timer != null){
                    timer.cancel();
                }

                //re-schedule timer here
                //otherwise, IllegalStateException of
                //"TimerTask is scheduled already" 
                //will be thrown
                timer = new Timer();
                myTimerTask = new MyTimerTask();

                if(optSingleShot.isChecked()){
                    //singleshot delay 1000 ms
                    timer.schedule(myTimerTask, 1000);
                }else{
                    //delay 1000ms, repeat in 5000ms
                    timer.schedule(myTimerTask, 1000, 1000);
                }
            }});

        btnCancel.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                if (timer!=null){
                    timer.cancel();
                    timer = null;
                }
            }
        });

    }

    class MyTimerTask extends TimerTask {

        @Override
        public void run() {
            Calendar calendar = Calendar.getInstance();
            SimpleDateFormat simpleDateFormat = 
                    //new SimpleDateFormat("dd:MMMM:yyyy HH:mm:ss a");
                    new SimpleDateFormat(" HH:mm:ss a");

            final String strDate = simpleDateFormat.format(calendar.getTime());

            //Calendar cal = Calendar.getInstance();
            //cal.setTime(new Date());
            final int hour = calendar.get(Calendar.HOUR_OF_DAY);
            final int minute = calendar.get(Calendar.MINUTE);

            System.out.println("HOUR:"+hour);
            System.out.println("MINUTE:"+minute);

            runOnUiThread(new Runnable(){


                @Override
                public void run() {
//135
                    if( hour >= 14 && hour <= 17) {
                        if (minute >= 45 && minute <= 59 || minute >= 00 && minute <=59 || minute >= 00 && minute <= 15 ) {
                            textCounter.setText(strDate);

                        } else {
                            timer.cancel();

                        }

                    }else{
                        timer.cancel();

                    }
                }});
        }

    }

}

但是timer总是在运行。 我错了什么？

有人可以帮助我吗？

感谢