If the Chart Data is empty and no limits are provided to axis, it should not throw an exception but it should default to a value.

[khanliKU]

if no max/min is provided in both axis and if there is no data, I believe it should default to min = 0, max = 1.

In my application I am displaying live RSSI data of BLE devices. When no BLE device is detected horizontal axis (time) is irrelevant. My chart computes X axis values from the x field of FlSpot x values.

Describe the bug When LineChartData is empty and maxX is null it throws the following exception:

══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
The following LateError was thrown building RSSIChart(dirty, dependencies:
[_InheritedProviderScope<PlotDataManager?>], state: _RSSIChartState#77d4d):
LateInitializationError: Field 'mostRightSpot' has not been initialized.

The relevant error-causing widget was:
  RSSIChart
  RSSIChart:file:///C:/Users/kutlay.hanli/AndroidStudioProjects/adi_attach/lib/main.dart:52:19

When the exception was thrown, this was the stack:
#0      LineChartBarData.mostRightSpot (package:fl_chart/src/chart/line_chart/line_chart_data.dart)
#1      LineChartHelper.calculateMaxAxisValues (package:fl_chart/src/chart/line_chart/line_chart_helper.dart:49:19)
#2      new LineChartData (package:fl_chart/src/chart/line_chart/line_chart_data.dart:93:31)

To Reproduce

Scaffold(
  body: SafeArea(
    child: LineChart(
      LineChartData(
        lineBarsData: null,
        maxY: -30,
        minY: -150,
      ),
    ),
  ),
);

Versions

Flutter 3.0.5 • channel stable • https://github.com/flutter/flutter.git
Framework • revision f1875d570e (8 weeks ago) • 2022-07-13 11:24:16 -0700
Engine • revision e85ea0e79c
Tools • Dart 2.17.6 • DevTools 2.12.2

fl_chart: ^0.55.1

[khanliKU]

https://github.com/imaNNeoFighT/fl_chart/pull/1142

[imaNNeo]

I couldn't reproduce it. There's no exception, and below is the result of your code in my machine (latest fl_chart version, 0.55.1):

[imaNNeo]

Please give me a valid reproducible code (a main.dart file). Or a video shot of what you're facing.

[khanliKU]

Hi,

To reproduce: https://github.com/imaNNeoFighT/fl_chart/pull/1142#issue-1366216416

Fixed the issue in this PR https://github.com/imaNNeoFighT/fl_chart/pull/1142/commits/36701547c8d86e3172e6c8c66912548f3556b68b

It is awaiting approval to merge.

[khanliKU]

I followed the contributing steps and it still failed. Can you help me understand why?

[khanliKU]

@imaNNeoFighT can you guide me?

[CodesbyRobot]

Please give me a valid reproducible code (a main.dart file). Or a video shot of what you're facing.

 LineChartBarData(
            spots: spots,
            dotData: FlDotData(show: false),
            color: Colors.blue,
          ),
          LineChartBarData(
            spots: spots2,
            dotData: FlDotData(show: false),
            color: Colors.green,
          ),
          LineChartBarData(
            spots: null,
            dotData: FlDotData(show: false),
            color: Colors.yellow,
          ),

I am having the same issue, Try with multiple LineChartBarData, with one being completely null.

[PetrachkovArtem]

Hi everyone! The code checks max position X and Y coordinates by spot elements. If your spot list is empty or null, use [FlSpot.zero] for the spot list by default. It helped me. Don't use [FlSpot.nullSpot]