Java - How to calculate the first and last day of each week

Question

I'm trying to create a weekly calendar that looks like this: http://dhtmlx.com/docs/products/dhtmlxScheduler/sample_basic.html

How can I calculate every week date? For example, this week is:

Monday - Sunday
7 June, 8 June, 9 June, 10 June, 11 June, 12 June, 13 June

Answer 1

Yes. Use Joda Time

http://joda-time.sourceforge.net/

Answer 2

If you know which day it is (Friday) and the current date (June 11), you can calculate the other days in this week.

Answer 3

I recommend that you use Joda Time library. Gregorian Calendar class has weekOfWeekyear and dayOfWeek methods.

Answer 4

First day of this week.

    Calendar c = Calendar.getInstance();
    while (c.get(Calendar.DAY_OF_WEEK) != Calendar.MONDAY) {
        c.add(Calendar.DATE, -1);
    }

Answer 5

The algorithm you're looking for (calculating the day of the week for any given date) is "Zeller's Congruence". Here's a Java implementation:

http://technojeeves.com/joomla/index.php/free/57-zellers-congruence

Answer 6

I guess this does what you want:

// Get calendar set to current date and time
Calendar c = Calendar.getInstance();

// Set the calendar to monday of the current week
c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);

// Print dates of the current week starting on Monday
DateFormat df = new SimpleDateFormat("EEE dd/MM/yyyy");
for (int i = 0; i < 7; i++) {
    System.out.println(df.format(c.getTime()));
    c.add(Calendar.DATE, 1);
}

Answer 7

You can build up on this: The following code prints the first and last dates of each week for 15 weeks from now.

Calendar c = Calendar.getInstance();
c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
for(int i=0; i<15; i++)
{
    System.out.print("Start Date : " + c.getTime() + ", ");
    c.add(Calendar.DAY_OF_WEEK, 6);
    System.out.println("End Date : " + c.getTime());
    c.add(Calendar.DAY_OF_WEEK, 1);
}