topic How to move (or dynamically create and delete) markers in Qt Maps SDK Questions

How to move (or dynamically create and delete) markers

KennSebesta — Thu, 05 Aug 2021 02:45:51 GMT

I have a very simple task for a QML app, but it's proving to be harder than I expected. I would like to display a set of markers, and then as a function of user input redraw a different set of markers. There are several examples I found for building geometries, but none of tearing them down, nor moving them.

What is the simplest way to accomplish this?

Re: How to move (or dynamically create and delete) markers

LucasDanzinger — Thu, 05 Aug 2021 14:13:15 GMT

To add a new graphic marker on the map, you can follow this sample - https://github.com/Esri/arcgis-runtime-samples-qt/tree/main/ArcGISRuntimeSDKQt_QMLSamples/DisplayInformation/Simple_Marker_Symbol

The graphic is the visual object, which contains geometry (where to display) and a symbol (how to display it).

After you have created a graphic, you can indefinitely assign new Point objects to the Graphic, and it will update (move) location:

e.g.

const pt = ArcGISRuntimeEnvironment.createObject("Point", {x: 1.2, y: 3.4}); graphic.geometry = pt;

To remove/tear down the graphic, simply remove the graphic from the graphics overlay:

e.g.

graphicsOverlay.graphics.removeOne(graphic);

https://developers.arcgis.com/qt/qml/api-reference/qml-esri-arcgisruntime-graphiclistmodel.html

Re: How to move (or dynamically create and delete) markers

KennSebesta — Mon, 09 Aug 2021 18:26:17 GMT

Thanks! As an addition to your suggestions, I also found that I could just nuke the entire set of points by `

graphicsOverlay.graphics.clear()

This lets me sidestep the problem of building the scaffold to tracking individual points separately.

Could I humbly suggest expanding the list of examples to include simple manipulation of points? I think what made it confusing is that move and remove markers can only happen in JS code, whereas the simple creation of the point happens quite naturally in QML.C.f. https://github.com/Esri/arcgis-runtime-samples-qt/blob/main/ArcGISRuntimeSDKQt_QMLSamples/DisplayInformation/Simple_Marker_Symbol/Simple_Marker_Symbol.qml#L5.