reactiveUtils

jasonwriter

Does anyone have an example of how to detect when a layer changes visibility? I'm trying to use the reactiveUtils but no luck. 

below is what I think should work and is in one of the reactiveUtils Samples but doesn't seem to work even in the sample. (it never triggers the callback function when i turn on and off layers).

// Use reactiveUtils to check when a Collection has changed
reactiveUtils.watch(
() => [view.map.allLayers.forEach((layer) => layer.visible)],
() => {

console.log("layer visibiblity changed")
let layerNames = "";
renderVisibleLayers(layerNames);
}
);

Or perhaps there is a better way to set up an event listener on all my layers for visibility?

Thanks in advance.

Jason.

 

UndralBatsukh

Hi there, 

So I did confirm that watching layer visibility is not working in the sample you mentioned. We will get it fixed in the sample ASAP. Thank you for bringing this to our attention. 

You can watch the operational layer visibilities the following way: 

view.when(()=>{
  view.map.layers.forEach((layer) => {
    reactiveUtils.watch(() => layer.visible, (visible) => {
      console.log(layer.title, "visible:", layer.visible)
    });
  });
});

 

Or for single layer you can just do the following: 

reactiveUtils.watch(() => layer.visible, (visible) => {
  console.log(layer.title, "visible:", layer.visible)
});