App Designer Error Message.

I randomly get the following error message in my app designer app.

1. How to I determine which line of code is causing the issue? The error does not occur when stepping through the code. Matlab does not provide a line number for the error/ warning.
2. How do fix the issue?

Warning: Error occurred while executing the listener callback for event Action defined for class matlab.graphics.interaction.graphicscontrol.AxesControl:

Dot indexing is not supported for variables of this type.

Error in matlab.graphics.interaction.graphicscontrol.InteractionObjects.DataTipBaseInteraction/response

Error in matlab.graphics.interaction.graphicscontrol.InteractionObjects.InteractionBase/responseevent

Error in matlab.graphics.interaction.graphicscontrol.InteractionObjects.InteractionBase

Error in matlab.graphics.interaction.graphicscontrol.GenericControl/process

Error in matlab.graphics.interaction.graphicscontrol.layoutable.LayoutableControl/process

Error in matlab.graphics.interaction.graphicscontrol.layoutable.GridLayoutableControl/process

Error in matlab.graphics.interaction.graphicscontrol.AxesControl/process

Error in matlab.graphics.interaction.graphicscontrol.ControlManager/processMessage

> In matlab.graphics.interaction.graphicscontrol/GenericControl/process

In matlab.graphics.interaction.graphicscontrol.layoutable/LayoutableControl/process

In matlab.graphics.interaction.graphicscontrol.layoutable/GridLayoutableControl/process

In matlab.graphics.interaction.graphicscontrol/AxesControl/process

In matlab.graphics.interaction.graphicscontrol/ControlManager/processMessage

Warning: Error occurred while executing the listener callback for event ButtonMotion defined for class matlab.graphics.primitive.canvas.HTMLCanvas:

Dot indexing is not supported for variables of this type.

Error in matlab.graphics.controls.internal.PointerMixin/hasUserModifiedPointer

Error in matlab.graphics.controls.internal.PointerMixin/updatePointer

Error in matlab.graphics.controls.WebToolbarController/handleMouseMotion

Error in matlab.graphics.controls.ToolbarController>@(e,d)obj.handleMouseMotion(e,d)

[dpb]

That's something broke in the internal TMW graphics code -- think you'll need to send this to official support to have any chance of any resolution.

Answer 1

[Yash]

Hi,

The line "Dot indexing is not supported for variables of this type." indicates that you are using dot indexing on wrong variable type. Dot indexing is generally used for struct and Table data types, not for arrays.

Also, see this line "Error occurred while executing the listener callback for event ButtonMotion defined for class matlab.graphics.primitive.canvas.HTMLCanvas:". This suggests that the error is in the callback function for the Button Motion event.

The best method to detect the error is to debug by creating breakpoints. Create breakpoints at the lines where you suspect the error might have occurred. When you would step in one by one, you will eventually get the line causing the error.

To remove the error you need to check the data type and apply the dot indexing properly.

If the issue is still not resolved, kindly share the code for better understanding.

[ILoveMATLAB]

Thank you for trying the to anwser the the question. As stated in the post, the error does not show up when "stepping through code". Thus, break points will not work for diagnosing the issue. When I step through my code there is no dot indexing error. This error is happening in Mathworks internal graphics code.

[dpb]

dbstop if error 

and

dbstack 

might be of some benefit here to pinpoint the way you get to the problem.

Were you able to followup on the previous suggestion to build a sample case that generates the problem and submit it to MW support?