Javascript API 4.2X Removing highlight from a specific feature (not all features)

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11-29-2021 11:27 AM
ShellyM
New Contributor III

Hi everyone,

I am using the highlight method (https://developers.arcgis.com/javascript/latest/api-reference/esri-views-layers-FeatureLayerView.htm... https://developers.arcgis.com/javascript/latest/sample-code/highlight-point-features/) on the map view to highlight individual points one by one based on user input from another part of my application.

 

highlighted = mapView.highlight(feature);

 

Given that there are multiple features highlighted, is there a way to selectively remove the highlight from a feature (perhaps using the ObjectId or attribute) without removing the highlight from all of the features?

Every example that I've seen so far suggests removing all of the highlights and then creating a new highlight with the new graphic or array of graphics, like so.

 

if (highlighted) {
     highlighted.remove();
}

highlighted = mapView.highlight(feature);  // new graphic or array of graphics

 

This technically works, but it creates an undesirable effect where the highlighted features briefly flash before showing the new highlighted selection. If possible, I do not want the highlighted features to flash when removing/updating a highlight.

I've been looking into this for a while now and haven't found a solution. I'm hoping there is some way to do it. It looks possible because the Feature Table widget has a highlightOnRowSelectEnabled property, and that works smoothly when adding/removing highlights, but I don't know if any part of that is transferable here.

Any help is much appreciated. Thanks in advance!

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shaylavi
Esri Contributor

I had a look at the API and you can use the following example -

view.allLayerViews.items[2]._highlightIds.delete(7423)

item #2 is the feature layer object - in your case, you'll need to recognise the right layer in the array of allLayersViews. You can do that in many way (hard coded like in my example would be the worse option.

Once you have the layer object available, you could have access to an object called _highlightIds which contains a map of all highlighted features. This array has a delete function that you pass an objectId you would like to remove as highlighted.

 

Shay

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7 Replies
shaylavi
Esri Contributor

Hi,

Have you tried to highlight all the relevant features again minus the one you want to remove the highlight for?

Shay
ShellyM
New Contributor III

Hi @shaylavi ,

Thanks for your reply. Yes, I have tried to call highlight again on the modified array. Added features get highlighted just fine, but any features that I remove from the array stay highlighted on the map (hence the need to remove all existing highlights before calling highlight again, but then this causes the flashing).

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shaylavi
Esri Contributor

Well, I haven't checked this myself but my guess is that when features are highlighted, it's a new separated graphic layer created, which you can access and modify manually. Once you are able to validate this, your next issue would probably be to recognise the right point you would like to remove, which surely can be solved easily with a filter based on an attribute. Hope that make sense

Shay
ShellyM
New Contributor III

Hi @shaylavi,

Thanks. Your explanation makes sense, but how do I access the separated graphic layer that was created so that I can query it for the right point? I don't have a reference to the layer, I don't know the ID, and it doesn't show up when I loop through all layers (I'm sure I'm overlooking something here).

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shaylavi
Esri Contributor

I had a look at the API and you can use the following example -

view.allLayerViews.items[2]._highlightIds.delete(7423)

item #2 is the feature layer object - in your case, you'll need to recognise the right layer in the array of allLayersViews. You can do that in many way (hard coded like in my example would be the worse option.

Once you have the layer object available, you could have access to an object called _highlightIds which contains a map of all highlighted features. This array has a delete function that you pass an objectId you would like to remove as highlighted.

 

Shay
ShellyM
New Contributor III

@shaylavi, that worked! Great! A BIG thank you! :)

I had to use _updateHighlight after removing the feature in order to see the change on the map.

 

const layer = view.allLayerViews.items.filter(d => d.layer.id === 'layer-id')[0]

layer._highlightIds.delete(id)  // feature - object id
layer._updateHighlight();

 

shaylavi
Esri Contributor

Cool, glad I could help

Shay
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