Question

I want to calculate the difference of days between two dates. My code works fine when the year of the date does not change, but when I calculate the difference between two dates like so: (13/01/2012 to 13/12/2011), it gives a negative value. It also gives wrong values of difference when I calculate the difference between today’s date and a future date. Please help me. Thank you in advance. Here is my code:

//getting values from text box
String fromtext = from.getText().toString();
String totext = to.getText().toString();
//sdf if a simple date formatter
SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy");
Date fromdate = (Date) sdf.parse(fromtext);
Date todate = (Date) sdf.parse(totext);

Calendar fromcal = Calendar.getInstance();
Calendar tocal = Calendar.getInstance();


    fromcal.setTime(fromdate);
    tocal.setTime(todate);// setting to date


    int reportDays=(int)(todate.getTime()-fromdate.getTime())/(3600*24*1000);

please tell me what is the best way to calculate the difference in days.

Answer 1

In addition to the format issue already mentionned, you are likely to have an overflow.
Try this:

int reportDays=(int)((todate.getTime()-fromdate.getTime())/(3600*24*1000));