Error: A value of type 'List<String>' can't be assigned to a variable of type 'List<ChartData>', trying to create a Chart with a list of Strings, - list

Question

I'm trying to create a graph and i don't know how to set values on this graph (I know how to set the values manually but i created a field in firestore that receives the value of x and y of the graph when you click on a button ), i'm using SyncFusion Flutter Chart (if you have any another idea to solve my problem feel free to say) and i'm trying to add the values ( String ) to the list and for that i Created in firestore when you click on the button (ChartData(x,y)) so all i need is add this string to the list of type ChartData, and for that i'm trying to use decode and split but now returned this error and i don't know how to solve. i'm sorry for the long text.
List<ChartData> convert(String input) {
List<ChartData> output;
try {
output = json.decode(input);
return output;
} catch (err) {
print('The input is not a string representation of a list');
return [ChartData(0, 0)];
}
}
List<ChartData> testim = testefinal.split(',');
final List<ChartData> list1 = convert(testefinal);
final List<ChartData> chartData = list1;
Error: A value of type 'List<String>' can't be assigned to a variable of type 'List<ChartData>'.
Full Code:
import 'dart:convert';
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: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"];
});
print(testefinal);
}
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 {
output = json.decode(input);
return output;
} catch (err) {
print('The input is not a string representation of a list');
return [ChartData(0, 0)];
}
}
List<ChartData> testim = testefinal.split(',');
final List<ChartData> list1 = convert(testefinal);
final List<ChartData> chartData = list1;
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;
}

Answer 1

I think, output = json.decode(input) as List();