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

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

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

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

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

  void _sort<T>(Comparable<T> getField(Dessert d), bool ascending) {
    _desserts.sort((Dessert a, Dessert b) {
      if (!ascending) {
        final Dessert 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 >= _desserts.length)
      return null;
    final Dessert dessert = _desserts[index];
    return new DataRow.byIndex(
      index: index,
      selected: dessert.selected,
      onSelectChanged: (bool value) {
        if (dessert.selected != value) {
          _selectedCount += value ? 1 : -1;
          assert(_selectedCount >= 0);
          dessert.selected = value;
          notifyListeners();
        }
      },
      cells: <DataCell>[
        new DataCell(new Text('${dessert.name}')),
        new DataCell(new Text('${dessert.calories}')),
        new DataCell(new Text('${dessert.fat.toStringAsFixed(1)}')),
        new DataCell(new Text('${dessert.carbs}')),
        new DataCell(new Text('${dessert.protein.toStringAsFixed(1)}')),
        new DataCell(new Text('${dessert.sodium}')),
        new DataCell(new Text('${dessert.calcium}%')),
        new DataCell(new Text('${dessert.iron}%')),
      ]
    );
  }

  @override
  int get rowCount => _desserts.length;

  @override
  bool get isRowCountApproximate => false;

  @override
  int get selectedRowCount => _selectedCount;

  void _selectAll(bool checked) {
    for (Dessert dessert in _desserts)
      dessert.selected = checked;
    _selectedCount = checked ? _desserts.length : 0;
    notifyListeners();
  }
}

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

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

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

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

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