charts
Bar Secondary Axis Axes Example
Example:
/// Bar chart example
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;
BarChartWithSecondaryAxis(this.seriesList, {this.animate});
factory BarChartWithSecondaryAxis.withSampleData() {
return new BarChartWithSecondaryAxis(
_createSampleData(),
// Disable animations for image tests.
animate: false,
);
}
@override
Widget build(BuildContext context) {
return new 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: new charts.NumericAxisSpec(
tickProviderSpec:
new charts.BasicNumericTickProviderSpec(desiredTickCount: 3)),
secondaryMeasureAxis: new charts.NumericAxisSpec(
tickProviderSpec:
new charts.BasicNumericTickProviderSpec(desiredTickCount: 3)),
);
}
/// Create series list with multiple series
static List<charts.Series<OrdinalSales, String>> _createSampleData() {
final globalSalesData = [
new OrdinalSales('2014', 5000),
new OrdinalSales('2015', 25000),
new OrdinalSales('2016', 100000),
new OrdinalSales('2017', 750000),
];
final losAngelesSalesData = [
new OrdinalSales('2014', 25),
new OrdinalSales('2015', 50),
new OrdinalSales('2016', 10),
new OrdinalSales('2017', 20),
];
return [
new charts.Series<OrdinalSales, String>(
id: 'Global Revenue',
domainFn: (OrdinalSales sales, _) => sales.year,
measureFn: (OrdinalSales sales, _) => sales.sales,
data: globalSalesData,
),
new 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);
}