Question

I am working with android + SQLite and DatePicker Widget.

The DatePicker does not format correctly for my SQLite insert commands. I.e, if the chosen date has a month or day less than 10, it does not insert the 0’s. For example if I choose the date “1st January 2010”, the format of the month and date is 1 and 1. This clashes with the usual SQL format of YYYY-MM-DD.

I tried to concatenate 0’s into the integers when they are less than 10 by casting them to strings and prefixing o’s by doing the following:

 // the callback received when the user "sets" the date in the dialog
private DatePickerDialog.OnDateSetListener mDateSetListener =
        new DatePickerDialog.OnDateSetListener() {

            public void onDateSet(DatePicker view, int year, 
                                  int monthOfYear, int dayOfMonth) {
                if(monthOfYear < 10)
                {
                    String mm = Integer.toString(monthOfYear);
                    String m = "0" + mm;
                    mMonth = Integer.parseInt(m);
                }
                else{mMonth = monthOfYear;}


                if (dayOfMonth <10)
                {
                    String dd = Integer.toString(dayOfMonth);
                    String d = "0" + dd;
                    dayOfMonth = Integer.parseInt(d);
                }
                else{mDay = dayOfMonth;}

                mYear = year;

                updateDisplay();
            }
        };


 // updates the date in the TextView
private void updateDisplay() {
    mDateDisplay.setText(
        new StringBuilder()
                // Month is 0 based so add 1
                .append(mYear).append("-")
                .append(mMonth + 1).append("-")
                .append(mDay).append("")
                );

    selecteddate = (String) mDateDisplay.getText();

}

I was expecting this to convert 2010-1-1 to 2010-01-01. It doesnt though. Does anyone have have a simpler way of doing this so that I can get the Date into the correct format before sending it to the sqlite table?

Thanks in advance.

Answer 1

SQLite doesn’t have Date/Time data types (http://www.sqlite.org/datatype3.html), so the ” usual SQL format of YYYY-MM-DD” isn’t the usual, in this case.

There are several date time functions (http://www.sqlite.org/lang_datefunc.html) but you can avoid those, most of the time, by just using the INTEGER data type on your date/time column and storing the epoch stamp (http://en.wikipedia.org/wiki/Unix_time).

DatePicker returns separate values for year/month/day of month, and month is zero-indexed. This is because it’s intended to work with Calendar (as evil as that may be). So with an INTEGER column, and something like this, you can store and retrieve date/times fine:

Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, datePicker.getYear());
cal.set(Calendar.MONTH, datePicker.getMonth());
cal.set(Calendar.DAY_OF_MONTH, datePicker.getDayOfMonth());
long datePubStamp = cal.getTimeInMillis();

Then store the datePubStamp in the INTEGER column.

To restore a Calendar just use Calendar.setTimeInMillis(<value_from_integer_db_column>). And, you can of course get a Date from a Calendar with getTime(), and then format with SimpleDateFormat, etc.