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javaandroiddategregorian-calendar

Android (Java) GregorianCalendar odd behavior

I have problem with java Date type. Why in my code days and days1 both equall 88?

GregorianCalendar dateNow = new GregorianCalendar(2014,03,31);
GregorianCalendar dateFirstDay = new GregorianCalendar(2014,01,01);
long diffInMillies = dateNow. getTimeInMillis() - dateFirstDay. getTimeInMillis();
int days = (int) (diffInMillies / (1000*60*60*24));

GregorianCalendar dateNow1 = new GregorianCalendar(2014,04,01);
GregorianCalendar dateFirstDay1 = new GregorianCalendar(2014,01,01);
long diffInMillies1 = dateNow1. getTimeInMillis() - dateFirstDay1. getTimeInMillis();
int days1 = (int) (diffInMillies1 / (1000*60*60*24));
Solution

  • The reason is that you are giving dateNow a month of 03, which means it is taking it as April, since it starts the month from 0. 0=Jan;1=Feb etc. Now, you are giving day of month as 31. Since April only has 30 days, it is incrementing and treating the date as 1 May, which is same as your dateNow1.

    Hence the same values.

    Hope this helps.