Android项目中利用CountDownTimer实现一个倒数功能

/**
 * 倒计时
 * 
 * @author admin
 * 
 */
public class MainActivity extends ActionBarActivity {

  private Button tvTime;// 显示时间
  private MyCountDownTimer myCountDownTimer;// 倒计时对象

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tvTime = (Button) findViewById(R.id.time);
    tvTime.setText("发送验证码");
    tvTime.setOnClickListener(new OnClickListener() {

      @Override
      public void onClick(View v) {

        start();

        tvTime.setEnabled(false);// 倒计时时不可点击

      }
    });
  }

  /**
   * 开始
   * 
   * @param view
   */
  public void start() {
    long countDownInterval = 1000;// 间隔时间
    long millisInFuture = 20000;// 时长
    myCountDownTimer = new MyCountDownTimer(millisInFuture,
        countDownInterval);
    myCountDownTimer.start();
  }



  /**
   * 结束
   * 
   * @param view
   */
  public void end() {
    if (myCountDownTimer != null) {
      myCountDownTimer.cancel();

    }
  }

  @Override
  protected void onDestroy() {
    super.onDestroy();
    end();
  }

  /**
   * 倒计时
   * 
   * @author admin
   * 
   */
  private class MyCountDownTimer extends CountDownTimer {

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

    // 可直接更新UI
    @Override
    public void onTick(long millisUntilFinished) {
      tvTime.setText("剩余时间：" + millisUntilFinished / 1000);// 转化为秒
    }

    @Override
    public void onFinish() {
      tvTime.setText("获取验证码");
      tvTime.setEnabled(true);// 当时间结束时才可以点击

    }

  }

}