绘制：
1.在pubspec.yaml中引入：fl_chart: 0.55.2
2.绘制：

import 'package:jade/utils/JadeColors.dart';
import 'package:util/easy_loading_util.dart';
import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';

class MyLineChart extends StatefulWidget {
   
  const MyLineChart({
   Key key}) : super(key: key);

  @override
  State<MyLineChart> createState() => _MyLineChartState();
}

class _MyLineChartState extends State<MyLineChart> with TickerProviderStateMixin{
   

 List<String> _tabs = ['近7日','近1月','近3月'];
  TabController _tabController;

  List<Color> gradientColors = [
    Colors.yellow,
    Colors.yellow,
  ];

  //进入后默认显示指示竖线和轨迹球的点
  FlSpot _defaultShowFlSpot = FlSpot(8, 4);
  //进入页面时默认显示的点上的竖线显隐开关
  bool _showSpotLine = true;


  List<String> get weekDays => const ['10.21', '10.22', '10.23', '10.24', '10.25', '10.26', '10.27'];

 @override
  void initState() {
   
    // TODO: implement initState
    super.initState();
    _tabController = TabController(
        length: _tabs.length,vsync: this);
  }

  @override
  void dispose() {
   
    // TODO: implement dispose
    _tabController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
   
    return Container(
      child: Column(
        children: <Widget>[
         _tabBarView(),
          _lineChartWidget()
        ],
      ),
    );
  }

//选项卡
  _tabBarView(){
   
    return Container(
      width: double.infinity,
      height: 120.w,
      margin: EdgeInsets.only(bottom: 20.w),
      decoration: BoxDecoration(
        color: JadeColors.lightGrey,
        borderRadius: BorderRadius.circular(5)
      ),
      child: Column(
        children: [
         Container(
           height: 70.w,
           child: TabBar(
             isScrollable: false,
             labelPadding: EdgeInsets.symmetric(horizontal: 0),
             indicator: BoxDecoration(
                 color: Colors.white,
                 borderRadius: BorderRadius.circular(5),
                 border: Border.all(width: 2,color: JadeColors.lightGrey)
             ),
             labelColor: Color(0xff333333),
             labelStyle: