Flutter 怎样导入csv数据并绘制图表呢？求指导

我能导入数据，就没法将导入的数据绘制图表。

mport 'dart:math';
import 'package:csv/csv.dart';
import 'package:flutter/material.dart';
import 'package:charts_flutter/flutter.dart' as charts;
import 'package:flutter/services.dart' show rootBundle;

class ChartTestPage extends StatelessWidget {
  //const ChartTestPage({Key key}) : super(key: key);
   List<List<dynamic>> _counter  = [];
   loadCSVFormAssets() async {
     final myData = await rootBundle.loadString("assets/testdata1.csv");
     List<List<dynamic>> csvTable = CsvToListConverter().convert(myData);
     print(csvTable);
     _counter.add(csvTable);
   //setState(() {});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("chart_flutter")),
      body: Column(children: [Container(height: 240, child: _simpleLine())]),
    );
  }

  Widget _simpleLine() {
    //var random = Random();
    loadCSVFormAssets();
    var data = [
      for (var i = 1; i < csvTable.length; i++)
        LinearSales(csvTable[i][0], csvTable[i][1])

      // LinearSales(0, random.nextInt(100)),
    ];

    var seriesList = [
      charts.Series<LinearSales, int>(
        id: 'Sales',
        colorFn: (_, __) => charts.MaterialPalette.blue.shadeDefault,
        domainFn: (LinearSales sales, _) => sales.year,
        measureFn: (LinearSales sales, _) => sales.sales,
        data: data,
      )
    ];

    return charts.LineChart(seriesList, animate: true);
  }
}

class LinearSales {
  final int year;
  final int sales;

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

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