Android Days between two dates

Please refer this code, this may help you.

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");
}

You should never use formula such 24 * 60 * 60 * 1000! Why? Because there is day saving time, and not all days have 24 hours, also what about leap year, that has +1 day. That's why there is a calendar class. If you do not want to put any external library to your project like Jodatime, you could use pure Calendar class with very efficient function:

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;
}

I've finally found the easiest way to deal with that. Here is my code:

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;
}

Hope it helps.

Here's a two line solution:

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

In this example it gets the number of days between date "testCalendar" and the current date.