Trackball and crosshair is not visible in Sfcartision from latest version 27.x.52

[upendra-bajpai]

Bug description

I had implemented trackball with version 24.x.x but recently I updated to latest version.
Now I can't see trackball or crosshair although I can see label on x axis hilighted while traversing.
Restoring to previous version I can see them again.
Is there anything which I need to update or it's a bug?

Ps.Thank you for this library

Steps to reproduce

Just update to 27.x.x for charts and impliment trackball in Sfcartision charts. Both Android and iOS can't show the trackball.

    _trackballBehavior = TrackballBehavior(
      enable: true,
      activationMode: ActivationMode.singleTap,
      lineType: TrackballLineType.vertical,
      lineColor: Colors.blue,
      markerSettings: TrackballMarkerSettings(
          color: Colors.white,
          borderColor: Colors.blue,
          borderWidth: 9,
          width: 5,
          height: 5,
          shape: DataMarkerType.circle,
          markerVisibility: TrackballVisibilityMode.visible),
      lineDashArray: [5, 5],
      builder: (BuildContext context, TrackballDetails trackballDetails) {
        final ChartData point = widget.data[trackballDetails.pointIndex!];
        // widget.onDataPointSelected.call(point);
        return Container(
          decoration: BoxDecoration(
            color: Colors.black.withOpacity(0.4),
            borderRadius: BorderRadius.circular(4),
          ),
          child: SectionSum(
              sum: (point.y! * 100).toInt(),
              textStyle: TextStyle(
                color: Colors.white,
                backgroundColor: Colors.black.withOpacity(0.4),
                fontFamily: GoogleFonts.poppins().fontFamily,
                fontSize: 12,
                fontWeight: FontWeight.w700,
              )),
        );
      },
    );

Screenshots or Video

Screenshots / Video demonstration

I can update if needed

Stack Traces

Stack Traces

No crashes available 

On which target platforms have you observed this bug?

iOS

Flutter Doctor output

Doctor output

[baconbyte]

I am seeing similar after just updating, I have a customised trackball, when I assign a custom builder the line no longer appears in 27.x.x but it did for 24.x.x

[baconbyte]

I had a quick look at the code in the debugger and it looks when I assign a custom builder the chartPointInfo collection is cleared before the line is drawn, it is not cleared when there isn't a custom builder assigned. I'm not sure where/when this is collection is cleared

void _drawTrackballLine(PaintingContext context, Offset offset, SfChartThemeData chartThemeData, ThemeData themeData) { if (chartPointInfo.isNotEmpty && lineType != TrackballLineType.none) { final Paint paint = Paint()

[upendra-bajpai]

Without custom builder is it working? I am trying but no luck. I am expecting someone from syncfustion team to take a look at it.

[baconbyte]

Yes, it works when there isn't a custom builder for me, but I need the builder.

[stephengibson83]

Commenting to bump this issue a bit. I am also encountering the same issue and hoping for a fix ASAP.

[Baranibharathip]

Hi @upendra-bajpai,

We have checked the mentioned issue 'trackball and crosshair is not visible in Charts' and tried to replicate it in SfCartesianChart with version 27.1.52 by,

1. Ensured on Windows, Android, and web platforms.
2. Ensured with trackball and crosshair behavior.
3. Ensured with trackball builder.

However, we were unable to reproduce it on our end. Please check the attached sample, and if you are still experiencing the issue, we request that you replicate it in the attached sample and provide us with more details regarding the specific scenario in which you are encountering this issue. This will help us to assist you more effectively.

Sample : GH_2125.zip

Regards,
Baranibharathi P.

[baconbyte]

I can get the example to work, in my code I have a setState in the builder - this seems to be causing the issue, when I comment it out the trackball is working but the setState notification is obviously no longer working

[baconbyte]

I've updated my code to use a ValueNotifier which it probably should have been using anyway instead of setState and it's working for me now.

Note though setState was working before I upgraded.

[Baranibharathip]

Hi Baconbyte,

We have reviewed your query and would like to inform you that TrackballBehavior.builder is implemented for customizing tooltip content based on the use case. Calling setState inside the builder can lead to issues, as it only executes when the trackball is displayed. Since trackballs are dynamically created and destroyed, this can disrupt the widget lifecycle, resulting in tooltips that may not render or update as expected. Therefore, we have restricted the usage of setState from the latest version and this is the default behavior of the trackball in SfCartesianChart.

Regards,
Baranibharathi P.