FlutterDataTableExample.dart

class _DataTableExample extends State<DataTableExample> {
  List<Map> data;
  bool sort;
  int iSortColumnIndex;
 
  @override
  void initState() {
    sort = true; // Note that in flutter ascending/descending icon are inversed
    iSortColumnIndex = 1;
    onCountSortColum(1, true);
    super.initState();
  }

  onNameSortColum(int columnIndex, bool ascending) {
    if (columnIndex == 0) {
      // Flutter considers the ascending logo as (↓) and descending icon as (↑).
      // Due to that fact descending order mechanism is being written in ascending block.
      if (ascending) {
        data.sort((a, b) => b['name'].compareTo(a['name']));
      } else {
        data.sort((a, b) => a['name'].compareTo(b['name']));
      }
    }
  }

  onCountSortColum(int columnIndex, bool ascending) {
    if (columnIndex == 1) {
      // Flutter considers the ascending logo as (↓) and descending icon as (↑).
      // Due to that fact descending order mechanism is being written in ascending block.
      if (ascending) {
        data.sort(
            (a, b) => b['count'].compareTo(a['count']));
      } else {
        data.sort(
            (a, b) => a['count'].compareTo(b['count']));
      }
    }
  }

  List<DataRow> _buildDataRows() {
    return data
        .map(
          (obj) => DataRow(cells: [
            DataCell(
              Text('${obj["name"]}'),
            ),
            DataCell(Text('${obj["count"]}')),
          ]),
        )
        .toList();
  }

  Widget _buildDataTable() {
    return DataTable(
      sortColumnIndex: iSortColumnIndex,
      sortAscending: sort,
      columns: [
        DataColumn(
            onSort: (columnIndex, ascending) {
              setState(() {
                sort = ascending;
                iSortColumnIndex = columnIndex;
              });
              onNameSortColum(columnIndex, ascending);
            },
            label: Text('Name',
                style: TextStyle(
                  fontWeight: FontWeight.bold,
                  letterSpacing: 1.0,
                ))),
        DataColumn(
          onSort: (columnIndex, ascending) {
            setState(() {
              sort = ascending;
              iSortColumnIndex = columnIndex;
            });
            onCountSortColum(columnIndex, ascending);
          },
          label: Text('Count',
              style: TextStyle(
                fontWeight: FontWeight.bold,
                letterSpacing: 1.0,
              )),
        ),
      ],
      rows: _buildDataRows(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          'DataTable Example',
        ),
        centerTitle: true,
      ),
      body: SingleChildScrollView(
        physics: AlwaysScrollableScrollPhysics(),
        child: _buildDataTable(),
      ),
    );
  }
}