Fl_chart: error while clicking on pie chart

Created on 27 Dec 2019 · 9Comments · Source: imaNNeoFighT/fl_chart

Unhandled Exception: NoSuchMethodError: The method '[]' was called on null.
when i am tapping or long tapping some times. getting this error and after that i am not able to get touch event.

i solved it by changing in one file named "PieChartPainter".

sectionsAngle was null and we are getting value of it by index.

to temporary solve it. i made following changes.

1) adding try catch.
2) checking section Angle is null or not and checking its length.

try {
      for (int i = 0; i < data.sections.length; i++) {
        final section = data.sections[i];
        if(sectionsAngle!=null)
        {
          if(sectionsAngle.length > i ) {
            double sectionAngle = sectionsAngle[i];

            tempAngle %= 360;
            sectionAngle %= 360;

            /// degree criteria
            final space = data.sectionsSpace / 2;
            final fromDegree = tempAngle + space;
            final toDegree = sectionAngle + tempAngle - space;
            final isInDegree = touchAngle >= fromDegree &&
                touchAngle <= toDegree;

            /// radius criteria
            final centerRadius = data.centerSpaceRadius;
            final sectionRadius = centerRadius + section.radius;
            final isInRadius = touchR > centerRadius && touchR <= sectionRadius;

            if (isInDegree && isInRadius) {
              foundSectionData = section;
              foundSectionDataPosition = i;
              break;
            }

            tempAngle += sectionAngle;
          }
        }
      }
    } on Exception catch(e)
    {
      print("caught");

    }
    catch(e)
    {
      print("caught");
    }

I dont know my way is right or not as i ddnt go through whole library code. but i am not getting this error now. kindly guide.

Pie Chart bug

Source

sohampandya00

All 9 comments

Hi there,
I didn't understand the problem,
may I ask you to provide a reproducible code (include the main function)?
Thanks!

imaNNeoFighT on 27 Dec 2019

════════ Exception caught by gesture ═══════════════════════════════════════════════════════════════
The following NoSuchMethodError was thrown while handling a gesture:
The method '[]' was called on null.
Receiver: null
Tried calling:

When the exception was thrown, this was the stack:

0 Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)

1 PieChartPainter._getTouchedDetails (package:fl_chart/src/chart/pie_chart/pie_chart_painter.dart:197:42)

2 PieChartPainter.handleTouch (package:fl_chart/src/chart/pie_chart/pie_chart_painter.dart:170:12)

3 PieChartState.build. (package:fl_chart/src/chart/pie_chart/pie_chart.dart:56:28)

4 LongPressGestureRecognizer._checkLongPressEnd. (package:flutter/src/gestures/long_press.dart:333:52)

...
Handler: "onLongPressEnd"
Recognizer: LongPressGestureRecognizer#7f88e
debugOwner: GestureDetector
state: possible
════════════════════════════════════════════════════════════════════════════════════════════════════

i'm getting this error when long press the chart with given sample code.