how to change format of date from string date

Question

I have date as a string like this

String date = \"11-12-2018\"

I want to change it to \"2018-12-11\"

with the same var

Answer 1

Try the code below that will work

1) Make method like below

public String changeDateFormat(String currentFormat, String requiredFormat, String dateString) {
        String result = "";

        SimpleDateFormat formatterOld = new SimpleDateFormat(currentFormat, Locale.getDefault());
        SimpleDateFormat formatterNew = new SimpleDateFormat(requiredFormat, Locale.getDefault());
        Date date = null;
        try {
            date = formatterOld.parse(dateString);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        if (date != null) {
            result = formatterNew.format(date);
        }
        return result;
    }//end of changeDateFormat()

1st argument of the method is your current date format in your case it will be 'dd-MM-yyyy'

2nd argument is output or requires date format in your case it will be 'yyyy-MM-dd'

3rd argument is your date that you want to change the format

2) Run the method like below

String oldFormatDate = "11-12-2018";
String myDate = changeDateFormat("dd-MM-yyyy", "yyyy-MM-dd", oldFormatDate);
Log.d(TAG, "Old formatted Date : " + oldFormatDate);
Log.d(TAG, "New Date is : " + myDate);

3) Output:

Old formatted Date : 11-12-2018
New Date is : 2018-12-11