Why setState isn't working inside selectionChanged method ?

[aMaqboolTapPayments]

I'm trying to use setState() inside this function but with this my onSelection method is not updating range.

void selectionChanged(DateRangePickerSelectionChangedArgs args) {
isSameDate(date1, date2) {
if (date2 == date1) {
return true;
}
if (date1 == null || date2 == null) {
return false;
}
return date1.month == date2.month && date1.year == date2.year && date1.day == date2.day;
}
int firstDayOfWeek = DateTime.sunday % 7;
int endDayOfWeek = (firstDayOfWeek - 1) % 7;
endDayOfWeek = endDayOfWeek < 0 ? 7 + endDayOfWeek : endDayOfWeek;
PickerDateRange ranges = args.value;

  DateTime date1 = ranges.startDate!;
  DateTime date2 = (ranges.endDate ?? ranges.startDate)!;

  if (date1.isAfter(date2)) {
    var date = date1;
    date1 = date2;
    date2 = date;
  }
  int day1 = date1.weekday % 7;
  int day2 = date2.weekday % 7;

  DateTime dat1 = date1.add(Duration(days: (firstDayOfWeek - day1) + 1));
  DateTime dat2 = date2.add(Duration(days: (endDayOfWeek - day2) + 1));

  if (!isSameDate(dat1, date1) || !isSameDate(dat2, date2)) {
    datePickerController.selectedRange = PickerDateRange(dat1, dat2);
    setState((){
    // do some update
    });
  }

}