Plotting lists of doubles in flutter - flutter

Question

I have one data type in my app which contains two lists:
class DeviceData {
List<double> frequency;
List<double> value;
DeviceData({this.frequency, this.value});
}
I don't want to separate the data types in my app into individual nums due to it being reused everywhere from displaying raw data to writing/reading from the database. I need to plot the two lists in Flutter with frequency on the y axis and value on x.
All the libraries/packages I found on pub.dev use a data model containing pure int/double values to plot the data which they then convert into a list of that data model. I want to use lists containing all of x and all of y data, not one containing one x frequency corresponding to one y value. How does one do that? What if I want to use a map to plot the data?
An example:
SfCartesianChart(
plotAreaBorderWidth: 0,
primaryXAxis: NumericAxis(
edgeLabelPlacement: EdgeLabelPlacement.shift,
interval: 2,
majorGridLines: MajorGridLines(width: 0)),
primaryYAxis: NumericAxis(
labelFormat: '{value}',
axisLine: AxisLine(width: 0),
majorTickLines: MajorTickLines(color: Colors.transparent)),
series: <LineSeries<DeviceData, List<num>>>[
LineSeries<DeviceData, List<num>>(
animationDuration: 1500,
dataSource: _result, //Contains List<DeviceData>
xValueMapper: (DeviceData data, _) => data.frequency,
yValueMapper: (DeviceData data, _) => data.value,
width: 2,
markerSettings: MarkerSettings(isVisible: true))
],
tooltipBehavior: TooltipBehavior(enable: true),
);
What am I doing wrong here?

Answer 1

You could easily map your current devideData into a List<SingleDeviceData>:
dataSource: List.generate(
deviceData.frequency.length,
(index) => SingleDeviceData(
frequency: deviceData.frequency[index],
value: deviceData.value[index],
),
).toList(),
Full source code for easy copy-paste:
import 'dart:math';
import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_charts/charts.dart';
void main() {
runApp(
MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Flutter Demo',
home: Scaffold(
body: MyWidget(),
),
),
);
}
class MyWidget extends StatelessWidget {
#override
Widget build(BuildContext context) {
return SfCartesianChart(
plotAreaBorderWidth: 0,
primaryXAxis: NumericAxis(
edgeLabelPlacement: EdgeLabelPlacement.shift,
interval: 2,
majorGridLines: MajorGridLines(width: 0)),
primaryYAxis: NumericAxis(
labelFormat: '{value}',
axisLine: AxisLine(width: 0),
majorTickLines: MajorTickLines(color: Colors.transparent)),
series: dataList
.map((deviceData) => LineSeries<SingleDeviceData, double>(
animationDuration: 1500,
dataSource: List.generate(
deviceData.frequency.length,
(index) => SingleDeviceData(
frequency: deviceData.frequency[index],
value: deviceData.value[index],
),
).toList(),
xValueMapper: (SingleDeviceData data, _) => data.frequency,
yValueMapper: (SingleDeviceData data, _) => data.value,
width: 2,
markerSettings: MarkerSettings(isVisible: true)))
.toList(),
tooltipBehavior: TooltipBehavior(enable: true),
);
}
}
class DeviceData {
List<double> frequency;
List<double> value;
DeviceData({this.frequency, this.value});
}
class SingleDeviceData {
final double frequency;
final double value;
SingleDeviceData({this.frequency, this.value});
}
final Random random = Random();
final List<DeviceData> dataList = List.generate(
10,
(_) => DeviceData(
frequency: List.generate(100, (_) => random.nextDouble() * 100)..sort(),
value: List.generate(100, (_) => random.nextDouble() * 10 - 3)
.fold([0], (prev, curr) => prev..add(prev.last + curr)),
),
);