两天之间的Android天数

Question

我想比较我的Android应用程序的两个日期,但我有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天前:

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

然后将其与当前日期(天数之间)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,这完全不是预期的.

我做错了什么,或者这是Calendar班级的问题？

Answer 1

这是一个双线解决方案:

long msDiff = Calendar.getInstance().getTimeInMillis() - testCalendar.getTimeInMillis();
long daysDiff = TimeUnit.MILLISECONDS.toDays(msDiff);

在此示例中,它获取日期"testCalendar"和当前日期之间的天数.

Answer 2

请参考此代码,这可能对您有所帮助.

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");
}

Answer 3

我终于找到了最简单的方法来解决这个问题.这是我的代码:

public int getTimeRemaining()
{
    Calendar sDate = toCalendar(this.dateEvent);
    Calendar eDate = toCalendar(System.currentTimeMillis());

    // Get the represented date in milliseconds
    long milis1 = sDate.getTimeInMillis();
    long milis2 = eDate.getTimeInMillis();

    // Calculate difference in milliseconds
    long diff = Math.abs(milis2 - milis1);

    return (int)(diff / (24 * 60 * 60 * 1000));
}

private Calendar toCalendar(long timestamp)
{
    Calendar calendar = Calendar.getInstance();
    calendar.setTimeInMillis(timestamp);
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);
    calendar.set(Calendar.MILLISECOND, 0);
    return calendar;
}

希望能帮助到你.

Answer 4

public long Daybetween(String date1,String date2,String pattern)
{
    SimpleDateFormat sdf = new SimpleDateFormat(pattern,Locale.ENGLISH);
    Date Date1 = null,Date2 = null;
    try{
        Date1 = sdf.parse(date1);
        Date2 = sdf.parse(date2);
    }catch(Exception e)
    {
        e.printStackTrace();
    }
    return (Date2.getTime() - Date1.getTime())/(24*60*60*1000);
}

Answer 5

    Date userDob = new SimpleDateFormat("yyyy-MM-dd").parse(dob);
    Date today = new Date();
    long diff =  today.getTime() - userDob.getTime();
    int numOfYear = (int) ((diff / (1000 * 60 * 60 * 24))/365);
    int numOfDays = (int) (diff / (1000 * 60 * 60 * 24));
    int hours = (int) (diff / (1000 * 60 * 60));
    int minutes = (int) (diff / (1000 * 60));
    int seconds = (int) (diff / (1000));

Answer 6

绝对不要使用24 * 60 * 60 * 1000这样的公式！为什么？因为有节省时间的时间，并且并非全天都有24小时，所以leap年也有+1天。这就是为什么有日历类的原因。如果您不想像Jodatime这样将任何外部库放入项目中，则可以使用具有非常高效功能的纯Calendar类：

public static int numDaysBetween(final Calendar c, final long fromTime, final long toTime) {
    int result = 0;
    if (toTime <= fromTime) return result;

    c.setTimeInMillis(toTime);
    final int toYear = c.get(Calendar.YEAR);
    result += c.get(Calendar.DAY_OF_YEAR);

    c.setTimeInMillis(fromTime);
    result -= c.get(Calendar.DAY_OF_YEAR);

    while (c.get(Calendar.YEAR) < toYear) {
        result += c.getActualMaximum(Calendar.DAY_OF_YEAR);
        c.add(Calendar.YEAR, 1);
    }

    return result;
}