Question

我一直在尝试为Android应用创建一个将圣诞节倒计时的代码。

这是我到目前为止所做的。

      Calendar thatDay = Calendar.getInstance();
      thatDay.setTime(new Date(0)); /* reset */
      thatDay.set(Calendar.DAY_OF_MONTH, 25);
      thatDay.set(Calendar.MONTH, 11); // 0-11 so 1 less
      thatDay.set(Calendar.YEAR, 2014);

      Calendar today = Calendar.getInstance();


     while (true)
     {


     long diff = thatDay.getTimeInMillis() - today.getTimeInMillis();
     long diffSec = diff / 1000;

     long days = diffSec / SECONDS_IN_A_DAY;
     long secondsDay = diffSec % SECONDS_IN_A_DAY;
     long seconds = secondsDay % 60;
     long minutes = (secondsDay / 60) % 60;
     long hours = (secondsDay / 3600); // % 24 not needed

  }

然而，当我尝试循环它时，它会产生太多输出。如何每秒显示代码更新？

请帮助!!

Answer 1

你的循环

while (true) {
    ...
}

永远不会终止，因为你内部没有break;。

相反，请尝试for循环：

import java.text.SimpleDateFormat;
import java.util.concurrent.TimeUnit;

SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
Date xmas = f.parse("2014-12-25");
for (long i = System.currentTimeMillis(); i < xmas.getTime(); i += TimeUnit.HOURS.toMillis(1)) { 
    long hours = TimeUnit.MILLISECONDS.toHours(xmas.getTime() - i);
    // do something with hours
}

这几个小时循环直到圣诞节，但你可以很容易地改变它。

请注意使用TimeUnit类而不是多行数学。

Answer 2

最好使用ScheduledExecutorService，它会重复到达目的地时间。它的优点是它不会在打印输出之间使用您的处理器时间。

    final ScheduledExecutorService service = new ScheduledThreadPoolExecutor(1);
    final Calendar thatDay = new GregorianCalendar(2014, 11, 25);
    final Calendar today = Calendar.getInstance();
    service.schedule(new Runnable() {

        @Override
        public void run() {
            long diff = thatDay.getTimeInMillis() - today.getTimeInMillis();
            long diffSec = diff / 1000;
            long days = diffSec / SECONDS_IN_A_DAY;
            long secondsDay = diffSec % SECONDS_IN_A_DAY;
            long seconds = secondsDay % 60;
            long minutes = (secondsDay / 60) % 60;
            long hours = (secondsDay / 3600); // % 24 not needed
            if (diff > 0) {
                ses2.schedule(this, 1, TimeUnit.SECONDS);
            }
        }
    }, 1, TimeUnit.SECONDS);

如何创建圣诞节的倒计时

2 个答案: