fcs/lib/charts/bar_chart.dart

import 'package:charts_flutter/flutter.dart' as charts;
import 'package:charts_flutter/flutter.dart';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:provider/provider.dart';
import 'package:fcs/charts/qtyby_customer_table.dart';
import 'package:fcs/model/chart_model.dart';
import 'package:fcs/model/product_model.dart';
import 'package:fcs/fcs/common/helpers/theme.dart';
import 'package:fcs/vo/po.dart';
import 'package:fcs/widget/local_text.dart';

class BarChart extends StatefulWidget {
  @override
  _BarChartState createState() => _BarChartState();
}

class _BarChartState extends State<BarChart> {
  static final numberFormatter = new NumberFormat("#,###");
  List<POChartData> chartSummary = new List();
  List<charts.Series<POChartData, String>> series;

  @override
  void initState() {
    super.initState();
    var chartModel = Provider.of<ChartModel>(context, listen: false);
    this.chartSummary = chartModel.chartSummary;
  }

  @override
  Widget build(BuildContext context) {
    var productModel = Provider.of<ProductModel>(context);
    if (this.chartSummary.isNotEmpty) {
      this.chartSummary.forEach((s) {
        productModel.products.forEach((p) {
          if (p.id == s.productID) {
            s.displayOrder = p.displayOrder;
          } else {
            return;
          }
        });
      });

      this
          .chartSummary
          .sort((s1, s2) => s1.displayOrder.compareTo(s2.displayOrder));
    }
    List<charts.Series<POChartData, String>> series = [
      charts.Series(
          id: "Subscribers",
          data: this.chartSummary,
          domainFn: (POChartData series, _) => series.productName,
          measureFn: (POChartData series, _) => series.balanceQty,
          colorFn: (POChartData series, _) =>
              charts.ColorUtil.fromDartColor(series.getColor),
          labelAccessorFn: (POChartData series, _) =>
              '${numberFormatter.format(series.balanceQty)}'),
    ];

    return Container(
      height: 200,
      child: Column(
        children: <Widget>[
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              LocalText(context, 'product.balance_qty',
                  color: primaryColor, fontSize: 16),
              IconButton(
                icon: Icon(
                  Icons.refresh,
                  color: primaryColor,
                ),
                onPressed: () {
                  _load();
                },
              )
            ],
          ),
          Expanded(
            child: charts.BarChart(
              series,
              animate: true,
              vertical: false,
              defaultRenderer: new charts.BarRendererConfig(
                barRendererDecorator: new charts.BarLabelDecorator<String>(
                  labelPosition: charts.BarLabelPosition.auto,
                ),
              ),
              selectionModels: [
                SelectionModelConfig(changedListener: (SelectionModel model) {
                  final selectedDatum = model.selectedDatum;
                  if (selectedDatum.isNotEmpty) {
                    selectedDatum.forEach((charts.SeriesDatum datumPair) {
                      Navigator.push(
                        context,
                        MaterialPageRoute(
                            builder: (context) => QtyByCustomerTable(
                                  poChartData: datumPair.datum,
                                )),
                      );
                    });
                  }
                })
              ],
            ),
          ),
        ],
      ),
    );
  }

  Future<void> _load() async {
    var chartModel = Provider.of<ChartModel>(context);
    var _s = await chartModel.loadSummary();
    setState(() {
      this.chartSummary = _s ?? [];
    });
  }
}