topic Re: handle/listen Layer visibility events in ArcGIS JavaScript Maps SDK Questions

handle/listen Layer visibility events

davizuco666 — Wed, 05 Apr 2023 09:40:31 GMT

I need to listen to layer visibility changes, but can´t figure out how to do it with Javascript 4.x SDK.

LayerList "trigger-action" never triggers on layer visibility changes.

I Tryed like:LayerList.on

But just working on "load" event..

Also triyed to see all events to find the right one, with no success.

Any ideas?

davizuco666 — Wed, 05 Apr 2023 10:34:22 GMT

Auto awnser:

layer.watch('visible', (visibility, a, eventName,layer) => { console.log("visible: ", visibility); console.log(layer, eventName, a); });

I don't understand why there is no mention of this in the documentation, watch is not even in the list of methods.

You just have to guess...

KenBuja — Wed, 05 Apr 2023 13:38:41 GMT

Have you seen this section in the Programming patterns page that discusses watching for property changes?

davizuco666 — Wed, 05 Apr 2023 15:27:19 GMT

No I didn´t 😅, it was quite hidden. 🤔 Thank you for the link! 😜

LaurenBoyd — Wed, 05 Apr 2023 15:52:37 GMT

@davizuco666 there is also a sample that shows how to take advantage of reactiveUtils and watch for when the map's layer visibility changes: https://developers.arcgis.com/javascript/latest/sample-code/watch-for-changes-reactiveutils/