Hi,
Unfortunately this does not solve the problem. I created an example for demonstration of the issue:
import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_charts/charts.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
bool ranged = false;
bool calculatedZoom = false;
DateTime? _startDate;
DateTime? _endDate;
@override
Widget build(BuildContext context) {
final List<ChartData> inData = [
ChartData(DateTime(2023, 1), 1000),
ChartData(DateTime(2023, 2), 100),
];
final List<ChartData> outData = [
ChartData(DateTime(2023, 1), -500),
ChartData(DateTime(2023, 2), -50),
];
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Column(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
children: [
Row(
children: [
const Text("Ranged"),
Switch(
// This bool value toggles the switch.
value: ranged,
activeColor: Colors.red,
onChanged: (bool value) {
// This is called when the user toggles the switch.
setState(() {
ranged = value;
_setDataRange();
});
}),
],
),
Expanded(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: SfCartesianChart(
enableSideBySideSeriesPlacement: false,
primaryYAxis: NumericAxis(
// minimum: min,
// maximum: max,
),
primaryXAxis: DateTimeAxis(
minimum: _startDate, maximum: _endDate),
legend: Legend(
isVisible: true, position: LegendPosition.top),
series: <ChartSeries<ChartData, DateTime>>[
ColumnSeries<ChartData, DateTime>(
dataSource: inData,
xValueMapper: (ChartData data, _) => data.x,
yValueMapper: (ChartData data, _) => data.y,
emptyPointSettings:
EmptyPointSettings(mode: EmptyPointMode.zero),
name: "in",
color: Colors.green,
opacity: 0.75,
),
ColumnSeries<ChartData, DateTime>(
dataSource: outData,
xValueMapper: (ChartData data, _) => data.x,
yValueMapper: (ChartData data, _) => data.y,
name: "out",
color: Colors.red,
opacity: 0.75,
emptyPointSettings:
EmptyPointSettings(mode: EmptyPointMode.zero),
),
])))
]),
);
}
_setDataRange() {
setState(() {
if (ranged) {
_startDate = DateTime(2023, 2);
_endDate = DateTime(2023, 3);
} else {
// fall back
_startDate = null;
_endDate = null;
}
});
}
}
class ChartData {
ChartData(this.x, this.y);
final DateTime x;
final double y;
}
Showing all data zooms fine. If you select the ranged data only the last part of data is shown but the zoom does not adapt. This results in unfavorable data view. If the data spread is even bigger the user might not see any data at all after selecting a range of data.
Can you provide a hint of to zoom the data when only a range of data is displayed? This should also work if the user is de-selecting on data series by tapping on the legend item.
