java - Android Days between two dates

Question

I want to compare two dates for my Android application, but I got a really weird issue.

For example:

If I set the back in the past date to 127 days ago:

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

And then compare it to the current date (Days between)

    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;

It will return 22 which is not at all what was expected.

Did I make something wrong or is that an issue with the Calendar class ?

Answer 1

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.