paginated table flutter

import 'dart:async';
import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

Future<List<Result>> fetchResults(http.Client client) async {
  final response = await client.get('https://api.myjson.com/bins/j5xau');

  // Use the compute function to run parseResults in a separate isolate
  return compute(parseResults, response.body);
}

// A function that will convert a response body into a List<Result>
List<Result> parseResults(String responseBody) {
  final parsed = json.decode(responseBody).cast<Map<String, dynamic>>();

  return parsed.map<Result>((json) => Result.fromJson(json)).toList();
}

class Result {
  final String sex;
  final String region;
  final int year;
  final String statistic;
  final String value;

  Result({this.sex, this.region, this.year, this.statistic, this.value});

  bool selected = false;

  factory Result.fromJson(Map<String, dynamic> json) {
    return Result(
      sex: json['sex'] as String,
      region: json['region'] as String,
      year: json['year'] as int,
      statistic: json['statistic'] as String,
      value: json['value'] as String,
    );
  }
}

class ResultsDataSource extends DataTableSource {
  final List<Result> _results;
  ResultsDataSource(this._results);

  void _sort<T>(Comparable<T> getField(Result d), bool ascending) {
    _results.sort((Result a, Result b) {
      if (!ascending) {
        final Result c = a;
        a = b;
        b = c;
      }
      final Comparable<T> aValue = getField(a);
      final Comparable<T> bValue = getField(b);
      return Comparable.compare(aValue, bValue);
    });
    notifyListeners();
  }

  int _selectedCount = 0;

  @override
  DataRow getRow(int index) {
    assert(index >= 0);
    if (index >= _results.length) return null;
    final Result result = _results[index];
    return DataRow.byIndex(
        index: index,
        selected: result.selected,
        onSelectChanged: (bool value) {
          if (result.selected != value) {
            _selectedCount += value ? 1 : -1;
            assert(_selectedCount >= 0);
            result.selected = value;
            notifyListeners();
          }
        },
        cells: <DataCell>[
          DataCell(Text('${result.sex}')),
          DataCell(Text('${result.region}')),
          DataCell(Text('${result.year}')),
          DataCell(Text('${result.statistic}')),
          DataCell(Text('${result.value}')),
        ]);
  }

  @override
  int get rowCount => _results.length;

  @override
  bool get isRowCountApproximate => false;

  @override
  int get selectedRowCount => _selectedCount;

  void _selectAll(bool checked) {
    for (Result result in _results) result.selected = checked;
    _selectedCount = checked ? _results.length : 0;
    notifyListeners();
  }
}

class DataTableDemo extends StatefulWidget {
  ResultsDataSource _resultsDataSource = ResultsDataSource([]);
  bool isLoaded = false;

  @override
  _DataTableDemoState createState() => _DataTableDemoState();
}

class _DataTableDemoState extends State<DataTableDemo> {
  ResultsDataSource _resultsDataSource = ResultsDataSource([]);
  bool isLoaded = false;
  int _rowsPerPage = PaginatedDataTable.defaultRowsPerPage;
  int _sortColumnIndex;
  bool _sortAscending = true;

  void _sort<T>(
      Comparable<T> getField(Result d), int columnIndex, bool ascending) {
    _resultsDataSource._sort<T>(getField, ascending);
    setState(() {
      _sortColumnIndex = columnIndex;
      _sortAscending = ascending;
    });
  }

  Future<void> getData() async {
    final results = await fetchResults(http.Client());
    if (!isLoaded) {
      setState(() {
        _resultsDataSource = ResultsDataSource(results);
        isLoaded = true;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    getData();
    return Scaffold(
        appBar: AppBar(
          title: const Text('Data tables'),
        ),
        body: ListView(padding: const EdgeInsets.all(20.0), children: <Widget>[
          PaginatedDataTable(
              header: const Text('Census Data'),
              rowsPerPage: _rowsPerPage,
              onRowsPerPageChanged: (int value) {
                setState(() {
                  _rowsPerPage = value;
                });
              },
              sortColumnIndex: _sortColumnIndex,
              sortAscending: _sortAscending,
              onSelectAll: _resultsDataSource._selectAll,
              columns: <DataColumn>[
                DataColumn(
                    label: const Text('Sex'),
                    onSort: (int columnIndex, bool ascending) => _sort<String>(
                        (Result d) => d.sex, columnIndex, ascending)),
                DataColumn(
                    label: const Text('Region'),
                    numeric: true,
                    onSort: (int columnIndex, bool ascending) => _sort<String>(
                        (Result d) => d.region, columnIndex, ascending)),
                DataColumn(
                    label: const Text('Year'),
                    numeric: true,
                    onSort: (int columnIndex, bool ascending) => _sort<num>(
                        (Result d) => d.year, columnIndex, ascending)),
                DataColumn(
                    label: const Text('Data'),
                    numeric: true,
                    onSort: (int columnIndex, bool ascending) => _sort<String>(
                        (Result d) => d.statistic, columnIndex, ascending)),
                DataColumn(
                    label: const Text('Value'),
                    numeric: true,
                    onSort: (int columnIndex, bool ascending) => _sort<String>(
                        (Result d) => d.value, columnIndex, ascending)),
              ],
              source: _resultsDataSource)
        ]));
  }
}

void main() {
  runApp(MaterialApp(home: DataTableDemo()));
}

Just wanted to say thank you for this. It helped me somewhere.

where is the url of the exported json coming from?

Just wanted to say thank you for this. It helped me somewhere.

can you help me , im new to flutter, i know how to connect flutter to google sheets but my problem is to make this code works

Just wanted to say thank you for this. It helped me somewhere.

can you help me , im new to flutter, i know how to connect flutter to google sheets but my problem is to make this code works

I haven't worked with Google Sheets, but as long as you're able to fetch the data into your app, the displaying it using a Paginated Table should work. What point are you having problems?