How to dynamically generate columns using JSON data in a Flutter DataTable (SfDataGrid)?.

In this article, we will show you how to dynamically generate columns using JSON data in a Flutter DataTable.

Initialize the SfDataGrid widget with all the necessary properties. Retrieve the JSON data using the http.get method and decode it. Then, convert the JSON data into a list collection. Once the data is loaded, the first item from the JSON (productlist[0]) is used to generate the columns. Each key in this first item becomes a column header by iterating over the key-value pairs of the first JSON object. The DataGridSource class maps the JSON data to the DataGrid rows. The columns are passed as an argument, and for each row, the values corresponding to those columns are extracted.

class JsonDataGridState extends State<JsonDataGrid> {

  late JsonDataGridSource jsonDataGridSource;
  List<dynamic> productlist = [];
  List<GridColumn> columns = [];

  Future generateProductList() async {
    var response = await rootBundle.loadString("assets/product.json");
    productlist = json.decode(response) as List<dynamic>;
    if (productlist.isNotEmpty) {
      // Generate columns dynamically from the first item in the list.
      columns = generateColumns(productlist[0]);
      jsonDataGridSource = JsonDataGridSource(productlist, columns);
    }
    return productlist;
  }

  List<GridColumn> generateColumns(Map<String, dynamic> data) {
    List<GridColumn> columns = [];

    for (var entry in data.entries) {
      GridColumn gridColumn = GridColumn(
        columnName: entry.key,
        label: Container(
          padding: const EdgeInsets.all(8),
          alignment: Alignment.center,
          child: Text(
            entry.key,
          ),
        ),
      );

      columns.add(gridColumn);
    }

    return columns;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Flutter DataGrid Sample'),
      ),
      body: FutureBuilder(
          future: generateProductList(),
          builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
            return snapshot.hasData
                ? SfDataGrid(
                    source: jsonDataGridSource,
                    columns: columns,
                    columnWidthMode: ColumnWidthMode.fill,
                  )
                : const Center(
                    child: CircularProgressIndicator(strokeWidth: 3),
                  );
          }),
    );
  }
}

class JsonDataGridSource extends DataGridSource {
….

  JsonDataGridSource(List<dynamic> productlist, List<GridColumn> columns) {
    dataGridRows = productlist
        .map<DataGridRow>((product) => DataGridRow(
                cells: columns.map<DataGridCell>((column) {
              return DataGridCell(
                  columnName: column.columnName,
                  value: product[column.columnName]);
            }).toList()))
        .toList();
  }
}

You can download this example on GitHub.