Blinking Chart when refreshing screen

[Peter]

Hi

I am recording Live data and displaying the data Live on the chart.

New data gets added to the FastLineSeries every 5 seconds.

So, what I did was to call setState() every 5 seconds and the whole chart blinks/flashes as it re-draw the first data to the last data. Maybe it has to do with the animation or timing? But can I have the chart showing the series and add new points without the whole screen blinking?

Hope to hear from you soon.

[Yuvaraj Gajaraj]

Hi Peter 

 

Greetings from Syncfusion. We have analyzed your scenario at our end, and we suspect that you are referring the animation as a flickering, you can disable the animation by specifying the animationDuration as zero in the series. And we recommend to you use the updateDataSource method instead of setState, because while calling the setStabte method it will render whole chart again, but in updateDataSource method it only updates the specific point only and internally we have ignored some unwanted code execution for updating the series alone. We have created a simple chart sample with updateDataSource method below for your reference.  

 

Sample: https://www.syncfusion.com/downloads/support/forum/169314/ze/forums_169314-712578441 

User guide: https://help.syncfusion.com/flutter/cartesian-charts/methods#updatedatasource  

 

Regards 

Yuvaraj 

[Peter]

I tried calling the function but I get the following error:

════════ Exception caught by rendering library ═════════════════════════════════

The data points should be available to render fast line series.

'package:syncfusion_flutter_charts/src/chart/series_painter/fastline_painter.dart':

package:syncfusion_flutter_charts/…/series_painter/fastline_painter.dart:1

Failed assertion: line 188 pos 14: 'seriesPoints.isNotEmpty'

The relevant error-causing widget was

SfCartesianChart

Another exception was thrown: The data points should be available to render fast line series.

The following RenderObject was being processed when the exception was fired: RenderCustomPaint#3c13a relayoutBoundary=up2:

  creator: CustomPaint ← RepaintBoundary ← Container ← Stack ← Container ← DecoratedBox ← Container ←

    DecoratedBox ← ConstrainedBox ← Container ← Listener ← _GestureSemantics ← ⋯

  parentData: <none> (can use size)

  constraints: BoxConstraints(0.0<=w<=1017.9, 0.0<=h<=499.0)

  size: Size(0.0, 0.0)

This RenderObject has no descendants.

Any hints?

[Peter]

Ok, I resolve this as I was not doing it correctly.

[Yuvaraj Gajaraj]

Hi Peter, 

 

Happy to hear the issue has been resolved at your end. Kindly get back to us, if you need further assistance. We are always happy in assisting you. 

 

Thanks, 

Yuvaraj. 

[??]

How did you solve this problem, I also encountered the same problem.

[Yuvaraj Gajaraj]

In the FastLineSeries it will remove the closest data points from the data source and render a series. So when using the FastLineSeries the data source list must be not empty, at least you have one data item otherwise it will through an assertion error.