Android 는 CountDownTimer 를 사용 하여 카운트다운 효 과 를 실현 합 니 다.

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

  private Button tvTime;//     
  private MyCountDownTimer myCountDownTimer;//      

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

      @Override
      public void onClick(View v) {

        start();

        tvTime.setEnabled(false);//         

      }
    });
  }

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



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

    }
  }

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

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

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

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

    @Override
    public void onFinish() {
      tvTime.setText("     ");
      tvTime.setEnabled(true);//            

    }

  }

}