samples/web/charts/lib/bar_chart/horizontal_bar_label.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.

/// Horizontal bar chart with bar label renderer example and hidden domain axis.
// EXCLUDE_FROM_GALLERY_DOCS_START
import 'dart:math';
// EXCLUDE_FROM_GALLERY_DOCS_END
import 'package:charts_flutter/flutter.dart' as charts;
import 'package:flutter/material.dart';

class HorizontalBarLabelChart extends StatelessWidget {
  final List<charts.Series> seriesList;
  final bool animate;

  HorizontalBarLabelChart(this.seriesList, {this.animate});

  /// Creates a [BarChart] with sample data and no transition.
  factory HorizontalBarLabelChart.withSampleData() {
    return new HorizontalBarLabelChart(
      _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 HorizontalBarLabelChart.withRandomData() {
    return new HorizontalBarLabelChart(_createRandomData());
  }

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

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

    return [
      new charts.Series<OrdinalSales, String>(
          id: 'Sales',
          domainFn: (OrdinalSales sales, _) => sales.year,
          measureFn: (OrdinalSales sales, _) => sales.sales,
          data: data,
          // Set a label accessor to control the text of the bar label.
          labelAccessorFn: (OrdinalSales sales, _) =>
              '${sales.year}: \$${sales.sales.toString()}')
    ];
  }
  // EXCLUDE_FROM_GALLERY_DOCS_END

  // [BarLabelDecorator] will automatically position the label
  // inside the bar if the label will fit. If the label will not fit and the
  // area outside of the bar is larger than the bar, it will draw outside of the
  // bar. Labels can always display inside or outside using [LabelPosition].
  //
  // Text style for inside / outside can be controlled independently by setting
  // [insideLabelStyleSpec] and [outsideLabelStyleSpec].
  @override
  Widget build(BuildContext context) {
    return new charts.BarChart(
      seriesList,
      animate: animate,
      vertical: false,
      // Set a bar label decorator.
      // Example configuring different styles for inside/outside:
      //       barRendererDecorator: new charts.BarLabelDecorator(
      //          insideLabelStyleSpec: new charts.TextStyleSpec(...),
      //          outsideLabelStyleSpec: new charts.TextStyleSpec(...)),
      barRendererDecorator: new charts.BarLabelDecorator<String>(),
      // Hide domain axis.
      domainAxis:
          new charts.OrdinalAxisSpec(renderSpec: new charts.NoneRenderSpec()),
    );
  }

  /// Create one series with sample hard coded data.
  static List<charts.Series<OrdinalSales, String>> _createSampleData() {
    final data = [
      new OrdinalSales('2014', 5),
      new OrdinalSales('2015', 25),
      new OrdinalSales('2016', 100),
      new OrdinalSales('2017', 75),
    ];

    return [
      new charts.Series<OrdinalSales, String>(
          id: 'Sales',
          domainFn: (OrdinalSales sales, _) => sales.year,
          measureFn: (OrdinalSales sales, _) => sales.sales,
          data: data,
          // Set a label accessor to control the text of the bar label.
          labelAccessorFn: (OrdinalSales sales, _) =>
              '${sales.year}: \$${sales.sales.toString()}')
    ];
  }
}

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

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