samples/web/charts/lib/axes/bar_secondary_axis.dart

// Copyright 2018 the Charts project authors. Please see the AUTHORS file
// for details.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/// Bar chart example
// EXCLUDE_FROM_GALLERY_DOCS_START
import 'dart:math';
// EXCLUDE_FROM_GALLERY_DOCS_END
import 'package:flutter/material.dart';
import 'package:charts_flutter/flutter.dart' as charts;

/// Example of using a primary and secondary axis (left & right respectively)
/// for a set of grouped bars. This is useful for comparing Series that have
/// different units (revenue vs clicks by region), or different magnitudes (2017
/// revenue vs 1/1/2017 revenue by region).
///
/// The first series plots using the primary axis to position its measure
/// values (bar height). This is the default axis used if the measureAxisId is
/// not set.
///
/// The second series plots using the secondary axis due to the measureAxisId of
/// secondaryMeasureAxisId.
///
/// Note: primary and secondary may flip left and right positioning when
/// RTL.flipAxisLocations is set.
class BarChartWithSecondaryAxis extends StatelessWidget {
  static const secondaryMeasureAxisId = 'secondaryMeasureAxisId';
  final List<charts.Series> seriesList;
  final bool animate;

  const BarChartWithSecondaryAxis(this.seriesList, {this.animate, Key key})
      : super(key: key);

  factory BarChartWithSecondaryAxis.withSampleData() {
    return BarChartWithSecondaryAxis(
      _createSampleData(),
      // Disable animations for image tests.
      animate: false,
    );
  }

  // EXCLUDE_FROM_GALLERY_DOCS_START
  // This section is excluded from being copied to the gallery.
  // It is used for creating random series data to demonstrate animation in
  // the example app only.
  factory BarChartWithSecondaryAxis.withRandomData() {
    return BarChartWithSecondaryAxis(_createRandomData());
  }

  /// Create random data.
  static List<charts.Series<OrdinalSales, String>> _createRandomData() {
    final random = Random();

    final globalSalesData = [
      OrdinalSales('2014', random.nextInt(100) * 100),
      OrdinalSales('2015', random.nextInt(100) * 100),
      OrdinalSales('2016', random.nextInt(100) * 100),
      OrdinalSales('2017', random.nextInt(100) * 100),
    ];

    final losAngelesSalesData = [
      OrdinalSales('2014', random.nextInt(100)),
      OrdinalSales('2015', random.nextInt(100)),
      OrdinalSales('2016', random.nextInt(100)),
      OrdinalSales('2017', random.nextInt(100)),
    ];

    return [
      charts.Series<OrdinalSales, String>(
        id: 'Global Revenue',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: globalSalesData,
      ),
      charts.Series<OrdinalSales, String>(
        id: 'Los Angeles Revenue',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: losAngelesSalesData,
      )..setAttribute(charts.measureAxisIdKey, secondaryMeasureAxisId)
      // Set the 'Los Angeles Revenue' series to use the secondary measure axis.
      // All series that have this set will use the secondary measure axis.
      // All other series will use the primary measure axis.
    ];
  }
  // EXCLUDE_FROM_GALLERY_DOCS_END

  @override
  Widget build(BuildContext context) {
    return charts.BarChart(
      seriesList,
      animate: animate,
      barGroupingType: charts.BarGroupingType.grouped,
      // It is important when using both primary and secondary axes to choose
      // the same number of ticks for both sides to get the gridlines to line
      // up.
      primaryMeasureAxis: const charts.NumericAxisSpec(
          tickProviderSpec:
              charts.BasicNumericTickProviderSpec(desiredTickCount: 3)),
      secondaryMeasureAxis: const charts.NumericAxisSpec(
          tickProviderSpec:
              charts.BasicNumericTickProviderSpec(desiredTickCount: 3)),
    );
  }

  /// Create series list with multiple series
  static List<charts.Series<OrdinalSales, String>> _createSampleData() {
    final globalSalesData = [
      OrdinalSales('2014', 5000),
      OrdinalSales('2015', 25000),
      OrdinalSales('2016', 100000),
      OrdinalSales('2017', 750000),
    ];

    final losAngelesSalesData = [
      OrdinalSales('2014', 25),
      OrdinalSales('2015', 50),
      OrdinalSales('2016', 10),
      OrdinalSales('2017', 20),
    ];

    return [
      charts.Series<OrdinalSales, String>(
        id: 'Global Revenue',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: globalSalesData,
      ),
      charts.Series<OrdinalSales, String>(
        id: 'Los Angeles Revenue',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: losAngelesSalesData,
      )..setAttribute(charts.measureAxisIdKey, secondaryMeasureAxisId)
      // Set the 'Los Angeles Revenue' series to use the secondary measure axis.
      // All series that have this set will use the secondary measure axis.
      // All other series will use the primary measure axis.
    ];
  }
}

/// Sample ordinal data type.
class OrdinalSales {
  final String year;
  final int sales;

  OrdinalSales(this.year, this.sales);
}