Widget DataTable has an built-in icon for sorting indication
How can I change the color or even the icon?
Scrollbar(
controller: _scrollController,
child: SingleChildScrollView(
controller: _scrollController,
scrollDirection: Axis.horizontal,
child: DataTable(
border: TableBorder.all(width: 0.2),
headingRowColor: MaterialStateProperty.resolveWith<Color?>(
(Set<MaterialState> states) {
return Styles.TableHeaderColor;
}),
columns: getColumns(TableTitles),
rows: getRows(),
sortColumnIndex: sortColumnIndex,
sortAscending: isAscending,
dataRowHeight: 50,
headingRowHeight: 40,
),
),
),

The icon use the IconThemeData, so either change that for the entire app, or for the specific widget. I.e. you can wrap your DataTable in a
Themewidget, something like this: