widthWithPadding property

Leave this empty if you want your PersianDatePicker to contain the whole width of the screen

If there is a Padding widget as parent of this widget and you want it to have a desired width too, simply make a sum of width and the padding. For example:

int desiredWidth = 400;
int horizontalPadding = 10;
widthWithPadding = desiredWidth + (horizontalPadding * 2)

If you only want a desired width and there are no Padding as it's parent, just pass the width

If there is Padding as it's parent and you want it to take the whole width, make a sum of your padding and

MediaQuery.of(context).size.width