adding date to calendar is not updating month

Question

I'm working on an android application and new to it.

I have to get date from user and then add 28 days and store it in database.

This is what I have done so far

private void saveDate() throws ParseException {
    DatabaseHelper db = new DatabaseHelper(ActivityPeriodToday.this.getActivity());

    String pDate = periodDate.getText().toString().trim();
    String pTime = periodTime.getText().toString().trim();
    String next_expected = getNextExpected(pDate);

    boolean isInserted = db.insertPeriodTodayIntoPeriods(pDate, pTime, early_late, pDifference, pType, next_expected);

    if (isInserted == true) {
        Toast.makeText(ActivityPeriodToday.this.getActivity(), "Saved", Toast.LENGTH_SHORT).show();

    } else {
        Toast.makeText(ActivityPeriodToday.this.getActivity(), "Could not be saved", Toast.LENGTH_SHORT).show();
    }

}

private String getNextExpected(String pDate) {
    SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
    Calendar c = Calendar.getInstance();
    try {
        c.setTime(sdf.parse(pDate));
    } catch (ParseException e) {
        e.printStackTrace();
    }

    c.add(Calendar.DAY_OF_MONTH, 28);
    return sdf.format(c.getTime());
}

But is code is not incrementing month.

Ex. If user selects 01/11/2016, then date is incremented and is saved 29/11/2016. But if user selects 16/11/2016 then saves date is 28/11/2016 but this should be 14/12/2016

Why adding 28 to 01/11/2016 is 28/11/2016? Shouldn't it be 29/11/2016? — Marat, Nov 16 '16 at 11:41
Are you sure you are getting the result wrong? Maybe you are checking wrong column or row? Because your code is ok and it is working. — Marat, Nov 16 '16 at 11:44

score 1 · Answer 1 · answered Nov 16 '16 at 11:15

1

Try using this:

calendar.add(Calendar.DAY_OF_YEAR, 28);

answered Nov 16 '16 at 11:15

MihaiV

695
6
14

score 1 · Accepted Answer · answered Nov 16 '16 at 11:17

1

Step 1

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            Calendar c = Calendar.getInstance();
            c.setTime(sdf.parse(dateInString));

Step-2 use add() to add number of days to calendar

c.add(Calendar.DATE, 40);

answered Nov 16 '16 at 11:17

Victor

4,171
1
29
37

score 0 · Answer 3 · answered Nov 16 '16 at 11:31

Its Working for me.

Calendar c = Calendar.getInstance();
            int Year = c.get(Calendar.YEAR);
            int Month = c.get(Calendar.MONTH);
            int Day = c.get(Calendar.DAY_OF_MONTH);
            //  current date
            String CurrentDate = Year + "/" + Month + "/" + Day;
            String dateInString = CurrentDate; // Start date
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            c = Calendar.getInstance();
            try {
                c.setTime(sdf.parse(dateInString));
            } catch (ParseException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            c.add(Calendar.DATE, 28);//insert the number of days that you want
            sdf = new SimpleDateFormat("dd/MM/yyyy");
            Date resultdate = new Date(c.getTimeInMillis());
            dateInString = sdf.format(resultdate);
            Toast.makeText(MainActivity.this, ""+dateInString, Toast.LENGTH_SHORT).show();

score 0 · Answer 4 · edited May 23 '17 at 11:53

0

Your question may already have an answer here: How can I increment a date by one day in Java?

Or you can simply use

c.add(Calendar.DATE, 28);

instead of

c.add(Calendar.DAY_OF_MONTH, 28);

edited May 23 '17 at 11:53

Community

1
1

answered Nov 16 '16 at 11:49

Dmitriy Kravchenko

1
4

adding date to calendar is not updating month

4 Answers4