List<String> to List<Object>

I want to convert a List of type String to a list of type ChartData, cause I'm creating a graph and the data (x,y) is saved on Firestore as string, so i converted the string to a List using split and now I have to convert this List of String to List of ChartData, I'm using Sync Fusion Chart. How can I do that? I tried using

 List<ChartData> b = strarray.map((e) => ChartData(5,1)).toList();

But i can't use it because When i try to use ChartData() it asks me to give the x and y.

The code: ´

import 'dart:convert';
import 'dart:ffi';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:mood3/telas/animacao.dart';
import 'package:ntp/ntp.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:syncfusion_flutter_charts/charts.dart';
import '../model/GraphMood.dart';


class Graph extends StatefulWidget {

  @override
  State<Graph> createState() => _GraphState();
}




class _GraphState extends State<Graph> {

  TooltipBehavior? _tooltipBehavior;
  DateTime ntpTime = DateTime.now();
String testefinal = '';
  _loadNTPTime() async {
    FirebaseAuth auth = FirebaseAuth.instance;
    FirebaseFirestore db = FirebaseFirestore.instance;
    setState(() async {
      ntpTime = await NTP.now();
    });
  }
  Future _recuperarNome() async {
    FirebaseAuth auth2 = FirebaseAuth.instance;
    User? user = auth2.currentUser;
    DocumentSnapshot ds = await db.collection('usuarios')
        .doc(user!.uid)
        .get();
    Map<String, dynamic> dss = ds.data() as Map<String, dynamic>;
    setState((){
      testefinal = dss["moodGraph"];
    });
  }

  FirebaseFirestore db = FirebaseFirestore.instance;

  @override
  initState(){
    _recuperarNome();
    _tooltipBehavior = TooltipBehavior(enable: true);
    super.initState();
    _loadNTPTime();
  }




  @override
  Widget build(BuildContext context) {
    List<ChartData> convert(String input) {
      List<ChartData> output;
      try {
        print(json);
        output = json.decode(input);
        return output;
      } catch (err) {
        print(err);
        return [ChartData(0, 0)];
      }
    }


   //List<ChartData> testim = testefinal.split(',');
    final List<ChartData> list1 = convert(testefinal);
    print(list1);
    //List<String> strs = <String>[testefinal];
    List<ChartData> dynamicValues = List<ChartData>.from(list1 as List);
    //print(strs.runtimeType);
   // List<int> numbers = strs.map(int.parse).toList();
   // print(numbers.runtimeType);
   // print(numbers);
    print(dynamicValues);
    List<String> strarray = testefinal.split(" ");
    print(strarray);
    List<ChartData> b = strarray.map((e) => ChartData(5,1)).toList();
   // List<ChartData> stringList = (jsonDecode(testefinal) as List<ChartData>).cast<ChartData>();
    //print("teste1 " + stringList.toString());
    final List<ChartData> chartData = b;



    return Scaffold(
        body: Center(
            child: Container(
                child: SfCartesianChart(

                    primaryXAxis: CategoryAxis(),
                    // Chart title
                    title: ChartTitle(text: 'Mood Chart'),
                    // Enable legend
                    legend: Legend(isVisible: true),
                    // Enable tooltip
                    tooltipBehavior: _tooltipBehavior,

                    series: <ChartSeries>[
                      // Renders line chart
                      LineSeries<ChartData, int>(
                          dataSource: chartData,
                          xValueMapper: (ChartData data, _) => data.x.toInt(),
                          yValueMapper: (ChartData data, _) => data.y
                      )
                    ]
                )
            )
        )
    );
  }
}
class ChartData {
  ChartData(this.x, this.y);
  final double x;
  final double y;
}

Basically, if i try to use the value " e " of the map on ChartData(x,y) List<ChartData> b = strarray.map((e) => ChartData(5,1) <---- here ).toList(); it says Error: Too few positional arguments: 2 required, 1 given. So i can't use the map here. And if i try to add the List of Strings to the list List chartData = [] it says Error: A value of type 'List String' can't be assigned to a variable of type 'List ChartData'. So i'm thinking on add the List of strings to the List of ChartData, or convert the list of strings to list of chartData, but i don't know how to do that