两个日期之间的Android天数

Question

我想比较我的Android应用程序的两个日期，但是遇到了一个非常奇怪的问题。

例如：

如果我将back in the past日期设置为127天之前：

this.dateEvent = System.currentTimeMillis() - (127 * 24 * 3600 * 1000)

然后将其与当前日期（两天之间）进行比较

    Calendar sDate = getDatePart(new Date(this.dateEvent));
    Calendar eDate = getDatePart(new Date(System.currentTimeMillis()));

    int daysBetween = 0;
    while (sDate.before(eDate))
    {
        sDate.add(Calendar.DAY_OF_MONTH, 1);
        daysBetween ++;
    }

    while (sDate.after(eDate))
    {
        eDate.add(Calendar.DAY_OF_MONTH, 1);
        daysBetween ++;
    }

    return daysBetween;

它将返回22，这根本不是预期的结果。

我做错什么了Calendar吗？还是班上有问题？

Answer 1

请参考此代码，这可能会对您有所帮助。

public String getCountOfDays(String createdDateString, String expireDateString) {
    SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy", Locale.getDefault());

    Date createdConvertedDate = null, expireCovertedDate = null, todayWithZeroTime = null;
    try {
        createdConvertedDate = dateFormat.parse(createdDateString);
        expireCovertedDate = dateFormat.parse(expireDateString);

        Date today = new Date();

        todayWithZeroTime = dateFormat.parse(dateFormat.format(today));
    } catch (ParseException e) {
        e.printStackTrace();
    }

    int cYear = 0, cMonth = 0, cDay = 0;

    if (createdConvertedDate.after(todayWithZeroTime)) {
        Calendar cCal = Calendar.getInstance();
        cCal.setTime(createdConvertedDate);
        cYear = cCal.get(Calendar.YEAR);
        cMonth = cCal.get(Calendar.MONTH);
        cDay = cCal.get(Calendar.DAY_OF_MONTH);

    } else {
        Calendar cCal = Calendar.getInstance();
        cCal.setTime(todayWithZeroTime);
        cYear = cCal.get(Calendar.YEAR);
        cMonth = cCal.get(Calendar.MONTH);
        cDay = cCal.get(Calendar.DAY_OF_MONTH);
    }


    /*Calendar todayCal = Calendar.getInstance();
    int todayYear = todayCal.get(Calendar.YEAR);
    int today = todayCal.get(Calendar.MONTH);
    int todayDay = todayCal.get(Calendar.DAY_OF_MONTH);
    */

    Calendar eCal = Calendar.getInstance();
    eCal.setTime(expireCovertedDate);

    int eYear = eCal.get(Calendar.YEAR);
    int eMonth = eCal.get(Calendar.MONTH);
    int eDay = eCal.get(Calendar.DAY_OF_MONTH);

    Calendar date1 = Calendar.getInstance();
    Calendar date2 = Calendar.getInstance();

    date1.clear();
    date1.set(cYear, cMonth, cDay);
    date2.clear();
    date2.set(eYear, eMonth, eDay);

    long diff = date2.getTimeInMillis() - date1.getTimeInMillis();

    float dayCount = (float) diff / (24 * 60 * 60 * 1000);

    return ("" + (int) dayCount + " Days");
}