whenever you open the input help for a date field (value help, F4 help) – the first day of the week in the calender is per default Monday:
You want to change the first day to e.g. Sunday?
Use the Badi CALENDAR_DEFINITION with method GET_FIRST_DAY_OF_WEEK.
The allowed values to change the parameter weekday are:
You may use the constants defined in class interface IF_CALENDAR_DEFINITION .
For example: in the calendar, the first day of the week always shall be Sunday. The coding needed in the method will simply be:
weekday = IF_CALENDAR_DEFINITION=>C_SUNDAY.