Flutter Charts: using double in tick spec - flutter

Question

I'm trying to do a chart on flutter and my numbers are decimal, but the charts flutter only let me use whole(int) ticks, that said my chart becomes very uggly.
I've tried to change my tick provider in many ways, but it doesn't seem to accept double in any way.
With this code I can generate a nice graph, but i just want my Measure Axis is between 3 and 4, and I wanted like, 3.1/3.2/3.3.
import 'dart:convert';
import 'package:charts_flutter/flutter.dart' as charts;
import 'package:flutter/material.dart';
import 'dart:async';
import 'package:http/http.dart' as http;
import 'dart:math';
class Graficos extends StatefulWidget {
#override
_GraficosState createState() => _GraficosState();
}
class _GraficosState extends State<Graficos> {
List<charts.Series> seriesList;
int qteMeses = 6;
bool baixou = false;
var jsonData;
List<LinearSales> dados = List();
List<double> precos = List();
double menorPreco = 0;
double maiorPreco = 0;
final myController = TextEditingController();
#override
void initState() {
super.initState();
_Carregar();
}
Future<String> _Carregar( ) async{
print('local');
var response = await _funcaoJson();
if(response.length != null) {
seriesList = await _pegaDados();
}
return 'ok';
}
#override
Widget build(BuildContext context) {
return Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
child: jsonData == null ?
Container(): Column(
children: <Widget>[
Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
child: new charts.TimeSeriesChart(seriesList,primaryMeasureAxis: new charts.NumericAxisSpec(
viewport: new charts.NumericExtents(menorPreco - 0.3, maiorPreco + 0.3), tickProviderSpec:
new charts.BasicNumericTickProviderSpec(desiredTickCount: 1)), behaviors: [
new charts.PanAndZoomBehavior(),
new charts.RangeAnnotation([
new charts.RangeAnnotationSegment(new DateTime(int.parse(((jsonData['pesquisa_total'][0]['pesquisas'][qteMeses]['data_publicacao']).toString()).split("\/")[2]),int.parse(((jsonData['pesquisa_total'][0]['pesquisas'][qteMeses]['data_publicacao']).toString()).split("\/")[1]),int.parse(((jsonData['pesquisa_total'][0]['pesquisas'][qteMeses]['data_publicacao']).toString()).split("\/")[0])),
new DateTime.now(), charts.RangeAnnotationAxisType.domain),
new charts.LineAnnotationSegment(
maiorPreco, charts.RangeAnnotationAxisType.measure,
endLabel: 'Maior Preco: $maiorPreco',
color: charts.MaterialPalette.gray.shade400),
new charts.LineAnnotationSegment(
menorPreco, charts.RangeAnnotationAxisType.measure,
startLabel: 'Menor preco: $menorPreco',
color: charts.MaterialPalette.gray.shade400),
]),
]),
),
],
),
);
}
List<charts.Series<LinearSales, DateTime>> _pegaDados() {
montaGrafico();
menorPreco = precos.reduce(min);
maiorPreco = precos.reduce(max);
return [
new charts.Series<LinearSales, DateTime>(
id: 'Preço',
displayName: 'Preço',
domainFn: (LinearSales sales, _) => sales.mes,
measureFn: (LinearSales sales, _) => sales.sales,
data: dados,
)
];
}
Future<void> montaGrafico() async {
for(var i = qteMeses; i >= 0; i--){
dados.add(
LinearSales(new DateTime(int.parse(((jsonData['pesquisa_total'][0]['pesquisas'][i]['data_publicacao']).toString()).split("\/")[2]),int.parse(((jsonData['pesquisa_total'][0]['pesquisas'][i]['data_publicacao']).toString()).split("\/")[1]),int.parse(((jsonData['pesquisa_total'][0]['pesquisas'][i]['data_publicacao']).toString()).split("\/")[0])), double.parse((jsonData['pesquisa_total'][0]['pesquisas'][i]['items'][0]['ranking'][0]['preco'].toString()).replaceAll(',', '.'))),
);
print(int.parse(((jsonData['pesquisa_total'][0]['pesquisas'][i]['data_publicacao']).toString()).split("\/")[0]));
precos.add(double.parse((jsonData['pesquisa_total'][0]['pesquisas'][i]['items'][0]['ranking'][0]['preco'].toString()).replaceAll(',', '.')));
}
}
var aux;
Future<String> _funcaoJson() async {
var data = await http.get(
'My secret http');
setState(() {
jsonData = jsonDecode(data.body);
});
return 'Sucesso';
}
}
class LinearSales {
final DateTime mes;
final double sales;
LinearSales(this.mes, this.sales);
}
´´´

Answer 1

I found something that can interest those who will see this answer. To display double on your axis you can do so :
In your TimeSeriesChart() widget :
TimeSeriesChart(
primaryMeasureAxis: new charts.NumericAxisSpec(
tickProviderSpec: new charts.StaticNumericTickProviderSpec(
_createTickSpec(),
),
),
),
Then you can create a function _createTickSpec() :
List<charts.TickSpec<num>> _createTickSpec() {
List<charts.TickSpec<num>> _tickProvidSpecs = new List<charts.TickSpec<num>>();
double d = minVal;
while (d <= maxVal) {
_tickProvidSpecs.add(new charts.TickSpec(d,
label: '$d%', style: charts.TextStyleSpec(fontSize: 14)));
d += 0.1;
}
}