定期更新Android TextView以显示倒计时

package com.sample;

import android.app.Activity;
import android.os.bundle;
import android.os.CountDownTimer;
import android.widget.TextView;

public class SampleTimer extends Activity {

    TextView tv; // textview to display the countdown

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceStatE) {
        super.onCreate(savedInstanceStatE);
        tv = new TextView(this);
        this.setContentView(tv);

         // 10000 is the starTing number (in milliseconds)
        // 1000 is the number to count down each time (in milliseconds)

        MyCount counter = new MyCount(10000,1000);
        counter.start();
    }


    // countdowntimer is an abstract class,so extend it and fill in methods
    public class MyCount extends CountDownTimer {

        public MyCount(long millisInFuture,long countDownInterval) {
            super(millisInFuture,countDownInterval);
        }

        @Override
        public void onFinish() {
            tv.setText("done!");
        }

        @Override
        public void onTick(long millisUntilFinished) {
            tv.setText("Left: " + millisUntilFinished / 1000);
        }
    }
}