onLazyLoad method

Implementation

Future<PlutoInfinityScrollRowsResponse> onLazyLoad(
    PlutoInfinityScrollRowsRequest request) async {
  // rows are filtered?
  var filter = request.filterRows.isNotEmpty;

  // rows are sorted?
  var sort = request.sortColumn != null && !request.sortColumn!.sort.isNone;

  // number of records to fetch
  var fetchSize = 50;

  // index of last row fetched
  var rowIdx = 0;
  if (request.lastRow != null) {
    var row = request.lastRow!;
    rowIdx = rows.contains(row) ? rows.indexOf(row) : 0;
  }

  // build rows
  if (filter || sort) {
    // build all
    buildAllRows();
  } else {
    buildOutRows(rowIdx + fetchSize);
  }

  // build the list
  List<PlutoRow> tempList = rows.toList();

  // filter the list
  if (filter) {
    tempList = applyFilters(tempList);
  }

  // sort the list
  if (sort) {
    tempList = applySort(tempList);
  }

  // Data needs to be implemented so that the next row
  // to be fetched by the user is fetched from the server according to the value of lastRow.
  //
  // If [request.lastRow] is null, it corresponds to the first page.
  // After that, implement request.lastRow to get the next row from the server.
  //
  // How many are fetched is not a concern in PlutoGrid.
  // The user just needs to bring as many as they can get at one time.
  //
  // To convert data from server to PlutoRow
  // You can convert it using [PlutoRow.fromJson].
  // In the example, PlutoRow is already created, so it is not created separately.
  Iterable<PlutoRow> fetchedRows = tempList.skipWhile(
          (row) => request.lastRow != null && row.key != request.lastRow!.key);

  if (request.lastRow == null) {
    fetchedRows = fetchedRows.take(fetchSize);
  } else {
    fetchedRows = fetchedRows.skip(1).take(fetchSize);
  }

  // await Future.delayed(const Duration(milliseconds: 500));

  // The return value returns the PlutoInfinityScrollRowsResponse class.
  // isLast should be true when there is no more data to load.
  // rows should pass a List<PlutoRow>.
  // total number of rows
  final bool isLast =
      fetchedRows.isEmpty || widget.model.getDataRowCount() < rows.length;

  // notify the user
  if (isLast && mounted) {
    //ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Last Page!')));
  }

  // convert to list
  var list = fetchedRows.toList();

  return Future.value(
      PlutoInfinityScrollRowsResponse(isLast: isLast, rows: list));
}