/** * 倒計時 *  * @author admin *  */public class MainActivity extends ActionBarActivity {  private Button tvTime;// 顯示時間  private MyCountDownTimer myCountDownTimer;// 倒計時對象  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    tvTime = (Button) findViewById(R.id.time);    tvTime.setText("發送驗證碼");    tvTime.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        start();        tvTime.setEnabled(false);// 倒計時時不可點擊      }    });  }  /**   * 開始   *    * @param view   */  public void start() {    long countDownInterval = 1000;// 間隔時間    long millisInFuture = 20000;// 時長    myCountDownTimer = new MyCountDownTimer(millisInFuture,        countDownInterval);    myCountDownTimer.start();  }  /**   * 結束   *    * @param view   */  public void end() {    if (myCountDownTimer != null) {      myCountDownTimer.cancel();    }  }  @Override  protected void onDestroy() {    super.onDestroy();    end();  }  /**   * 倒計時   *    * @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("剩余時間：" + millisUntilFinished / 1000);// 轉化為秒    }    @Override    public void onFinish() {      tvTime.setText("獲取驗證碼");      tvTime.setEnabled(true);// 當時間結束時才可以點擊    }  }}