在charts_flutter小部件中使用NumericEndPointsTickProviderSpec在图形外部呈现的条形图

import 'package:charts_flutter/flutter.dart' as charts;

final data = [
  new LinearSales('2014', 10),
  new LinearSales('2015', 12),
  new LinearSales('2016', 8),
  new LinearSales('2017', 14),
];

final series = [
  new charts.Series<LinearSales, String>(
    id: 'Sales',
    domainFn: (LinearSales sales, _) => sales.year,
    measureFn: (LinearSales sales, _) => sales.sales,
    data: data,
  ),
];

final chart = new charts.BarChart(
  series,
  animate: true,
);

chart.primaryMeasureAxis?.tickProvider = new charts.NumericEndPointsTickProviderSpec();

new charts.PaddedScaffold(
  body: new SizedBox(
    height: 200.0,
    child: chart,
  ),
)