data_table_demo.dart

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';

class Desert {
  Desert(this.name, this.calories, this.fat, this.carbs, this.protein, this.sodium, this.calcium, this.iron);
  final String name;
  final int calories;
  final double fat;
  final int carbs;
  final double protein;
  final int sodium;
  final int calcium;
  final int iron;

  bool selected = false;
}

class DesertDataSource extends DataTableSource {
  final List<Desert> _deserts = <Desert>[
    new Desert('Frozen yogurt',                        159,  6.0,  24,  4.0,  87, 14,  1),
    new Desert('Ice cream sandwich',                   237,  9.0,  37,  4.3, 129,  8,  1),
    new Desert('Eclair',                               262, 16.0,  24,  6.0, 337,  6,  7),
    new Desert('Cupcake',                              305,  3.7,  67,  4.3, 413,  3,  8),
    new Desert('Gingerbread',                          356, 16.0,  49,  3.9, 327,  7, 16),
    new Desert('Jelly bean',                           375,  0.0,  94,  0.0,  50,  0,  0),
    new Desert('Lollipop',                             392,  0.2,  98,  0.0,  38,  0,  2),
    new Desert('Honeycomb',                            408,  3.2,  87,  6.5, 562,  0, 45),
    new Desert('Donut',                                452, 25.0,  51,  4.9, 326,  2, 22),
    new Desert('KitKat',                               518, 26.0,  65,  7.0,  54, 12,  6),

    new Desert('Frozen yogurt with sugar',             168,  6.0,  26,  4.0,  87, 14,  1),
    new Desert('Ice cream sandwich with sugar',        246,  9.0,  39,  4.3, 129,  8,  1),
    new Desert('Eclair with sugar',                    271, 16.0,  26,  6.0, 337,  6,  7),
    new Desert('Cupcake with sugar',                   314,  3.7,  69,  4.3, 413,  3,  8),
    new Desert('Gingerbread with sugar',               345, 16.0,  51,  3.9, 327,  7, 16),
    new Desert('Jelly bean with sugar',                364,  0.0,  96,  0.0,  50,  0,  0),
    new Desert('Lollipop with sugar',                  401,  0.2, 100,  0.0,  38,  0,  2),
    new Desert('Honeycomb with sugar',                 417,  3.2,  89,  6.5, 562,  0, 45),
    new Desert('Donut with sugar',                     461, 25.0,  53,  4.9, 326,  2, 22),
    new Desert('KitKat with sugar',                    527, 26.0,  67,  7.0,  54, 12,  6),

    new Desert('Frozen yogurt with honey',             223,  6.0,  36,  4.0,  87, 14,  1),
    new Desert('Ice cream sandwich with honey',        301,  9.0,  49,  4.3, 129,  8,  1),
    new Desert('Eclair with honey',                    326, 16.0,  36,  6.0, 337,  6,  7),
    new Desert('Cupcake with honey',                   369,  3.7,  79,  4.3, 413,  3,  8),
    new Desert('Gingerbread with honey',               420, 16.0,  61,  3.9, 327,  7, 16),
    new Desert('Jelly bean with honey',                439,  0.0, 106,  0.0,  50,  0,  0),
    new Desert('Lollipop with honey',                  456,  0.2, 110,  0.0,  38,  0,  2),
    new Desert('Honeycomb with honey',                 472,  3.2,  99,  6.5, 562,  0, 45),
    new Desert('Donut with honey',                     516, 25.0,  63,  4.9, 326,  2, 22),
    new Desert('KitKat with honey',                    582, 26.0,  77,  7.0,  54, 12,  6),

    new Desert('Frozen yogurt with milk',              262,  8.4,  36, 12.0, 194, 44,  1),
    new Desert('Ice cream sandwich with milk',         339, 11.4,  49, 12.3, 236, 38,  1),
    new Desert('Eclair with milk',                     365, 18.4,  36, 14.0, 444, 36,  7),
    new Desert('Cupcake with milk',                    408,  6.1,  79, 12.3, 520, 33,  8),
    new Desert('Gingerbread with milk',                459, 18.4,  61, 11.9, 434, 37, 16),
    new Desert('Jelly bean with milk',                 478,  2.4, 106,  8.0, 157, 30,  0),
    new Desert('Lollipop with milk',                   495,  2.6, 110,  8.0, 145, 30,  2),
    new Desert('Honeycomb with milk',                  511,  5.6,  99, 14.5, 669, 30, 45),
    new Desert('Donut with milk',                      555, 27.4,  63, 12.9, 433, 32, 22),
    new Desert('KitKat with milk',                     621, 28.4,  77, 15.0, 161, 42,  6),

    new Desert('Coconut slice and frozen yogurt',      318, 21.0,  31,  5.5,  96, 14,  7),
    new Desert('Coconut slice and ice cream sandwich', 396, 24.0,  44,  5.8, 138,  8,  7),
    new Desert('Coconut slice and eclair',             421, 31.0,  31,  7.5, 346,  6, 13),
    new Desert('Coconut slice and cupcake',            464, 18.7,  74,  5.8, 422,  3, 14),
    new Desert('Coconut slice and gingerbread',        515, 31.0,  56,  5.4, 316,  7, 22),
    new Desert('Coconut slice and jelly bean',         534, 15.0, 101,  1.5,  59,  0,  6),
    new Desert('Coconut slice and lollipop',           551, 15.2, 105,  1.5,  47,  0,  8),
    new Desert('Coconut slice and honeycomb',          567, 18.2,  94,  8.0, 571,  0, 51),
    new Desert('Coconut slice and donut',              611, 40.0,  58,  6.4, 335,  2, 28),
    new Desert('Coconut slice and KitKat',             677, 41.0,  72,  8.5,  63, 12, 12),
  ];

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

  int _selectedCount = 0;

  @override
  DataRow getRow(int index) {
    assert(index >= 0);
    if (index >= _deserts.length)
      return null;
    final Desert desert = _deserts[index];
    return new DataRow.byIndex(
      index: index,
      selected: desert.selected,
      onSelectChanged: (bool value) {
        if (desert.selected != value) {
          _selectedCount += value ? 1 : -1;
          assert(_selectedCount >= 0);
          desert.selected = value;
          notifyListeners();
        }
      },
      cells: <DataCell>[
        new DataCell(new Text('${desert.name}')),
        new DataCell(new Text('${desert.calories}')),
        new DataCell(new Text('${desert.fat.toStringAsFixed(1)}')),
        new DataCell(new Text('${desert.carbs}')),
        new DataCell(new Text('${desert.protein.toStringAsFixed(1)}')),
        new DataCell(new Text('${desert.sodium}')),
        new DataCell(new Text('${desert.calcium}%')),
        new DataCell(new Text('${desert.iron}%')),
      ]
    );
  }

  @override
  int get rowCount => _deserts.length;

  @override
  bool get isRowCountApproximate => false;

  @override
  int get selectedRowCount => _selectedCount;

  void _selectAll(bool checked) {
    for (Desert desert in _deserts)
      desert.selected = checked;
    _selectedCount = checked ? _deserts.length : 0;
    notifyListeners();
  }
}

class DataTableDemo extends StatefulWidget {
  static const String routeName = '/data-table';

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

class _DataTableDemoState extends State<DataTableDemo> {
  int _rowsPerPage = PaginatedDataTable.defaultRowsPerPage;
  int _sortColumnIndex;
  bool _sortAscending = true;
  DesertDataSource _desertsDataSource = new DesertDataSource();

  void _sort/*<T>*/(Comparable<dynamic/*=T*/> getField(Desert d), int columnIndex, bool ascending) {
    _desertsDataSource._sort/*<T>*/(getField, ascending);
    setState(() {
      _sortColumnIndex = columnIndex;
      _sortAscending = ascending;
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(title: new Text('Data tables')),
      body: new Block(
        padding: const EdgeInsets.all(20.0),
        children: <Widget>[
          new PaginatedDataTable(
            header: new Text('Nutrition'),
            rowsPerPage: _rowsPerPage,
            onRowsPerPageChanged: (int value) { setState(() { _rowsPerPage = value; }); },
            sortColumnIndex: _sortColumnIndex,
            sortAscending: _sortAscending,
            onSelectAll: _desertsDataSource._selectAll,
            columns: <DataColumn>[
              new DataColumn(
                label: new Text('Dessert (100g serving)'),
                onSort: (int columnIndex, bool ascending) => _sort/*<String>*/((Desert d) => d.name, columnIndex, ascending)
              ),
              new DataColumn(
                label: new Text('Calories'),
                tooltip: 'The total amount of food energy in the given serving size.',
                numeric: true,
                onSort: (int columnIndex, bool ascending) => _sort/*<num>*/((Desert d) => d.calories, columnIndex, ascending)
              ),
              new DataColumn(
                label: new Text('Fat (g)'),
                numeric: true,
                onSort: (int columnIndex, bool ascending) => _sort/*<num>*/((Desert d) => d.fat, columnIndex, ascending)
              ),
              new DataColumn(
                label: new Text('Carbs (g)'),
                numeric: true,
                onSort: (int columnIndex, bool ascending) => _sort/*<num>*/((Desert d) => d.carbs, columnIndex, ascending)
              ),
              new DataColumn(
                label: new Text('Protein (g)'),
                numeric: true,
                onSort: (int columnIndex, bool ascending) => _sort/*<num>*/((Desert d) => d.protein, columnIndex, ascending)
              ),
              new DataColumn(
                label: new Text('Sodium (mg)'),
                numeric: true,
                onSort: (int columnIndex, bool ascending) => _sort/*<num>*/((Desert d) => d.sodium, columnIndex, ascending)
              ),
              new DataColumn(
                label: new Text('Calcium (%)'),
                tooltip: 'The amount of calcium as a percentage of the recommended daily amount.',
                numeric: true,
                onSort: (int columnIndex, bool ascending) => _sort/*<num>*/((Desert d) => d.calcium, columnIndex, ascending)
              ),
              new DataColumn(
                label: new Text('Iron (%)'),
                numeric: true,
                onSort: (int columnIndex, bool ascending) => _sort/*<num>*/((Desert d) => d.iron, columnIndex, ascending)
              ),
            ],
            source: _desertsDataSource
          )
        ]
      )
    );
  }
}