onChartTouchInteractionUp only for taps and not long press, pan, zoom, etc.

[KD]

I'm using onChartTouchInteractionUp to get notified of the end of a tap event. I need the exact dx/dy coordinate of the tap so that I can use pixelToPoint of the appropriate series controller to get an interpolated value on the X/Y axis the corresponding point to the tap. This is all working perfectly.

However, onChartTouchInteractionUp is being called not just for regular taps, but also at the end of a long press, after the mouse was used to click/drag (panning), end of zooming, etc.

How can I distinguish in onChartTouchInteractionUp if it's just the end of a regular tap vs the end of these other kinds of events?

Thanks!

[Lokesh Palani]

Hi KD,

You can achieve your requirement by using the onChartTouchInteractionUp callback in the SfCartesianChart. To ignore the coordinate point during LongPress, panning, and zooming, we have declared a condition to check whether it is onChartTouchInteractionUp and onChartTouchInteractionDown offset value is equal, and longPress is false. Only then it calculates the x and y coordinate point. We have shared a code snippet and workaround sample for your reference, which you can modify based on your case. Please let us know if you need any further assistance.

Code snippet:

onChartTouchInteractionUp: (ChartTouchInteractionArgs args) {

                final Offset value = Offset(args.position.dx, args.position.dy);

                if (_position == value && _isLongPress == false) {

                  CartesianChartPoint<dynamic> chartPoint =

                      seriesController!.pixelToPoint(value);

                  print(' X point: ${chartPoint.x}');

                  print(' Y point: ${chartPoint.y}');

                }

                _isLongPress = false;

              },

              onChartTouchInteractionDown: (ChartTouchInteractionArgs args) {

                _position = Offset(args.position.dx, args.position.dy);

              },

 

Regards,

Lokesh.

Attachment: chart_182481_96014259.zip

[KD]

Thanks. I found a more robust solution by using the https://pub.dev/packages/gesture_x_detector package, which provides the XGestureDetector widget. This widget can be a parent widget of SfCartesianChart. Underneath the covers this uses the low-level Listener widget and so does not interfere with the GestureDetector inside of SfCartesianChart.

[Lokesh Palani]

Hi KD,

Most Welcome. Kindly get back to us if you have further queries. We are always happy to assist you.

Regards,

Lokesh.