爱华网介绍定时执行在一段时间后停止的倒计时，在倒计时执行过程中会在固定间隔得到通知（触发onTick方法），下面的例子显示在一个文本框中显示一个20s倒计时：
倒计时类public class CountDownUtils extends CountDownTimer {
private final String tag = "CountDownUtils";private TextView tv_display;
public CountDownUtils(long millisInFuture, longcountDownInterval,TextView _tv_display) {super(millisInFuture, countDownInterval);// TODO Auto-generated constructor stubLog.i(tag, "CountDownUtils.........");Log.i(tag, "" + _tv_display.getText());tv_display = _tv_display;}
@Overridepublic void onFinish() {// TODO Auto-generated method stubLog.i(tag, "CountDownUtils....onFinish.....");
}
@Overridepublic void onTick(long millisUntilFinished) {// TODO Auto-generated method stubLog.i(tag, "CountDownUtils....onTick....." +millisUntilFinished / 1000);tv_display.setText("还有:" + millisUntilFinished / 1000 + "s");
}
}
调用new CountDownUtils(30000, 500,tv_countdown).start();
Demo地址：Android倒计时DEMO下载密码：123456
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