topic Re: How to force a refresh on a FeatureLayer in ArcGIS JavaScript Maps SDK Questions

How to force a refresh on a FeatureLayer

PHerk — Mon, 02 Mar 2020 12:51:30 GMT

We have a WebMap with a FeatureLayer. The FeatureLayer has 2 sublayers. One has areas (polygons) where you can click on, the other layer should be visible after a click on the area. This is accomplished by a filter. If a field in the FeatureLayer.attributes is filled with a value, the polygon is visible in the color defined in ArcGIS online portal. In the Javascript code I return a value in the specific field. That works. The refresh() command does not update the polygon on the screen. The issue is that I have to reload the browser to see the change on the screen. The layer is updated by using the zoom buttons, but I can't find a method to refresh the layer in code, or even better, refresh the polygon. I made a silly hidescreen -> zoom in -> zoom out -> show screen function to have the layer refreshed by controlling the zoom buttons, but I can't imagine there are no other options. Found various similar questions in this community portal, tried all suggestions but there is no success.

Who has a solution?

Appreciated.

Re: How to force a refresh on a FeatureLayer

Egge-Jan_Pollé — Mon, 02 Mar 2020 16:04:49 GMT

Hi P Herk‌,

What about the refresh() method?

refresh() - FeatureLayer | ArcGIS API for JavaScript 4.14

Cheers,

Egge-Jan

Re: How to force a refresh on a FeatureLayer

PHerk — Mon, 02 Mar 2020 16:57:10 GMT

refresh() method does not update the graphics in the map....

Re: How to force a refresh on a FeatureLayer

Noah-Sager — Tue, 03 Mar 2020 23:30:00 GMT

Not sure I understand what a FeatureLayer with sublayers is, but perhaps the load() method is what you want:

FeatureLayer.load() - API Reference

Re: How to force a refresh on a FeatureLayer

JohnGrayson — Tue, 03 Mar 2020 23:49:18 GMT

Having a simple CodePen (or similar) that demonstrates the workflow normally helps others understand the issue and provide suggestions.

Re: How to force a refresh on a FeatureLayer

PHerk — Wed, 04 Mar 2020 08:46:12 GMT

OK, you are right. I will ask my customer to make a map public, put up the Codepen and we can go from there. Thank you all for the replies.

Re: How to force a refresh on a FeatureLayer

PHerk — Wed, 04 Mar 2020 16:55:49 GMT

OK the CodePen is working.

https://codepen.io/powerm/pen/BaNwNzd?editors=1010

The featurelayer has 2 layers. One layer has 4 polygons with colors Purple, Olive, Red and Blue. Always visible.

The second layer has the same polygons, in the color green, but initial invisible because of a filter setting.

The filter is set, so the layer polygon is invisible depending of a value in a Dat_uitv field.

No value, no polygon visible.

A valid date value, a green polygon visible.

The goal is that a polygon can be clicked, a timestamp will be set in the Dat_uitv field in the FeatureLayer. This results in a visible second layer by a green color.

This works for 3 polygons, the purple one excluded.

When these 3 polygons are clicked, the Dat_uitv belonging to the graphic is set with the actual date/time stamp.

For this sample, a second click on the polygon, removes the date and clears the Dat_uitv field, so the polygon will have only layer visible, the original color.

You can toggle as much as you like.

So, by clicking on the polygon the date is constructed and returned to ArcGIS online through the ApplyEdits() function.

This works like a charm, except, the screen is not updated, and a call to refresh() does not help.

When the polygon is clicked, and the screen is redrawn, the polygon shows the second layer, because the date field Dat_uitv, has a valid date value.

The only 2 ways to force the graphics to show the correct layer, is a zoom in / zoom out, or pan the polygons uit of the screen, and pan back.

I am looking for a way to update the screen, so I see the correct layers directly after a click on the polygon.

Currently I made a function where I zoom the screen but that is pretty ridiculous, because you need a delay etc. etc.

I would be very pleased if I can get directions how a direct screen update, refresh, redrawn, can be achieved by a function or command.

I do not want to redraw the whole FeatureLayer, because this is just a sample with a few field. The Featurelayer for a client has hundreds of polygons...

Re: How to force a refresh on a FeatureLayer

JohnGrayson — Wed, 04 Mar 2020 18:27:50 GMT

Is your intent to work with the layers in the Web Map? If so, you should find the specific FeatureLayer you want to update that has been added to the map (via the Web Map) instead of creating a new instance.

Re: How to force a refresh on a FeatureLayer

PHerk — Wed, 04 Mar 2020 18:56:35 GMT

Hi John, that is correct, but using this: webMap.findLayerById('b7408a1c740d401288521f3834088778') does not work.

b7408a1c740d401288521f3834088778 is the id of the Featurelayer in ArcGIS online.

Re: How to force a refresh on a FeatureLayer

JohnGrayson — Fri, 10 Dec 2021 23:23:49 GMT

To find a layer that is currently in the view, you can find it via the 'layers' collection of the map:

view.when(()=>{
 const myFeatureLayer = view.map.layers.find(layer=>{ 
   return (layer.title === "Vlakken - gereed");
 }); 
 console.info(myFeatureLayer.title, myFeatureLayer.id);
);‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

The id of the layer in the Web Map is different than the id of the portal item.

Re: How to force a refresh on a FeatureLayer

PHerk — Wed, 04 Mar 2020 20:49:39 GMT

Hi John,

Thank you for your help. Really appreciated!

I changed the CodePen according to your suggestions, but unfortunately it doesn't make any difference. I changed the layer from the second ("Vlakken - gereed") to the first ("Vlakken") otherwise the Date value field will not get written. What I don't understand is that the Featurelayer ID is not the long ID number from the ArcGIS online portal, but anyhow. Seems the reference is correct. Still the same problem, the graphic is not updated with a refresh(). Only using the zoom buttons, or pan the map.

Re: How to force a refresh on a FeatureLayer

JohnGrayson — Thu, 05 Mar 2020 22:10:17 GMT

Working with the correct layer that is already in the view is one issue we can address simply. Unfortunately, I'm still confused as to what you're trying to do and what is expected behavior. Some additional checks would be to look at the renderer and the definitionExpression property of the layer(s) to make sure they don't conflict with the edits being made. Currently, your code only works with and edits 1 layer. However, your Web Map has 3 Feature Layers and your comment about a FeatureLayer having 2 layers is misleading; a FeatureLayer instance only references 1 layer as indicated by the 'layerId' property. Also, I don't understand how changing the 'Dat_uitv' value will affect either the rendering or defintionExpression, so what is it you expect to happen when you update this value?

Here's a modified version of the codepen, but I still don't understand what the overall goal is for this task:

https://codepen.io/john-grayson/pen/dyoVKqX?editors=1001

Re: How to force a refresh on a FeatureLayer

PHerk — Fri, 06 Mar 2020 11:28:41 GMT

OK, John. What I want to do. This is a requirement from a customer. They have a map with area's / polygons, that indicate a specific location where a certain task:

- should start ( the area is in a color, Purple, Blue or Olive, each color represents a certain task)

- is finished ( the job in this area is done, the color must be Green).

A task is a work job, that a worker must do, example: cleaning the area.

The customer has, (indeed you are correct, sorry for the misleading information), 3 instances of a Featurelayer on his map:

1. Vloer (Dutch for floor)

2. Vlakken (Dutch for area's)

3. Vlakken - gereed (Ducth for area's completed)

It is the same Featurelayer, and the viewable area's on the layers depend on the filter:

1. Vloer, filter setting: only displays the area with id 5, this is the purple area.

2. Vlakken, filter setting: display the area's where id <> 5, the other 3 area's

3. Vlakken - gereed, filter setting: display the area's where id <> 5 AND Attribute: "Dat_uitv" is not empty.

This is the setting my customer made, and he wanted met to fill the "Dat_uitv" attribute with the current date time stamp, when they click on the specific area. Doing that, the map displays which area's have the job finished by showing the area "Vlakken - gereed" layer, according to the filter. Once the "Dat_uitv" attribute has a valid value, the filter of layer "Vlakken - gereed" is TRUE, and this layer displays the area in the color green. The customer can also view the timestamp when this job is finished. This works.

The customer is under the impression, filling the field would have an immediate action where the "Vlakken - gereed" layer is redrawn, refreshed. That is not the case, and should be triggered by an action. This is the question: how to get this done, without a zoom or pan interaction of the user. A browser refresh, zoom or pan action does update the layer...

Maybe the whole interpretation how to solve this is wrong. If there is a better way, let me know.

Hope it is clear now.

Thanks

Pete.

Re: How to force a refresh on a FeatureLayer

JohnGrayson — Tue, 10 Mar 2020 17:18:54 GMT

Pete,

I believe the issue you are seeing is that the attribute value you are editing will have no effect on the defintionExpression or renderer of that feature layer and that is why the layer does not change. The "Vlakken - gereed" layer is the one that that will be affected by the edit and is the one we want to call refresh() on.

https://codepen.io/john-grayson/pen/dyoVKqX?editors=1001

Re: How to force a refresh on a FeatureLayer

PHerk — Tue, 10 Mar 2020 18:21:46 GMT

YES! Thank you John. Appreciated!