topic Duplicate layers in TOC widget in ArcGIS JavaScript Maps SDK Questions

Duplicate layers in TOC widget

CM2 — Fri, 21 Mar 2014 16:12:44 GMT

Hey folks,

I'm having an issue where layers I'm using in Nliu's TOC are showing up double in the TOC.

Check out my code on JSFiddle here: http://jsfiddle.net/749QG/1/

Weird! I'm not sure why it's doing that - does so no matter what service I use.

Thanks for any suggestions,

Craig

Re: Duplicate layers in TOC widget

JonathanUihlein — Fri, 21 Mar 2014 16:33:21 GMT

It looks like you are creating a new TOC every time a layer is added to your map.

Your map has multiple layers being added, so the 'layer-add-result' is firing multiple times.

Re: Duplicate layers in TOC widget

CM2 — Sun, 12 Dec 2021 04:06:26 GMT

I don't see how that can be?

One layer is added to the TOC (once):

layerInfos: [{
              layer: dynaLayer1,
              title: "McKenzie Parcels",
              //collapsed: true
              slider: true
              }]

and one layer is added to the map (once):

map.addLayers([dynaLayer1]);

How would I set it so that the TOC isn't firing more than it should?

Re: Duplicate layers in TOC widget

JonathanUihlein — Fri, 21 Mar 2014 17:07:20 GMT

Hi! Thanks for the response. There are two errors with your current sample so let's fix those.

First, you are using parser.parse(); when you already have both "parseOnLoad: true" and "dojo/domReady!" in your code.
I noticed that you were copy/pasting code from Nliu's sample, which included the parser.

These can all be used in different situations. You may find value in reading documentation about the following modules: "dojo/parser", "dom/ready", "dojo/domReady!". Also read about the 'parseOnLoad' djConfig property.

Secondly, you reference dom nodes that do not exist in your sample. Remove the following lines and your sample seems to work for me.

dojo.byId("ChangeFeatureRenderer").disabled = false; dojo.byId("SetVisibleLayersProgramatically").disabled = false; dojo.byId("FindNodeByLayer").disabled = false; dojo.byId("InsertNewLayer").disabled = false;

*edit,

You should always use try/catch blocks if you suspect a problem in a specific section of code.
I also recommend browser-based development tools for troubleshooting problems like these.

Re: Duplicate layers in TOC widget

MichaelVolz — Fri, 21 Mar 2014 17:15:57 GMT

I am having the same issue when I use my own mapservice, so I cannot help out with this specific problem.

I do have some items to add about this TOC widget though. The first instance of the layers in the TOC is not dynamic, so if you have layers with scale dependencies the top TOC never changes but the bottom TOC does so the top TOC is the problem. The bottom TOC does not respect group layers as I have a group layer with scale dependencies, but the group layer never expands in the bottom TOC.

Re: Duplicate layers in TOC widget

BrettGreenfield__DNR_ — Fri, 21 Mar 2014 18:25:07 GMT

The TOC is being loaded twice, for some reason. I got rid of the entire toc.on section, and it only loaded once. Strangely, I also got rid of toc.startup() and again, the TOC loaded but only once. I'm not familiar with Nilu's TOC so I don't know exactly how it works, but if the things within the toc.on function aren't necessary, it looks like you can just get rid of those and the TOC will be fine.

Re: Duplicate layers in TOC widget

CM2 — Fri, 21 Mar 2014 19:40:19 GMT

Interesting; thanks for the replies, everyone. Jon's removal of code worked for me. I thought I had tried that, but I must have removed too much.

Brett your suggestion worked for me as well.

Clearly I had been removing too much or too little when I was trying. Thanks a lot, guys. Is it obvious that I'm new to this? 😄

I'll certainly do some more reading. Thanks again. This is working: http://jsfiddle.net/749QG/4/

Re: Duplicate layers in TOC widget

MayJeff — Tue, 06 May 2014 13:43:10 GMT

I am so new to JavaScript API and try to change version to 3.9 on this sample:
http://jsfiddle.net/749QG/4/ but found error message on console when using Firefox. Can someone try to explain it?
Thanks.

Re: Duplicate layers in TOC widget

KenBuja — Sun, 12 Dec 2021 04:06:29 GMT

You have both

        var djConfig = {
            parseOnLoad: true,
            packages: [{
                "name": "agsjs",
                "location": "http://gmaps-utility-gis.googlecode.com/svn/tags/agsjs/latest/build/agsjs"
            }]
        };

and

parser.parse();

Use one or the other. And take a look at this page on parseOnLoad vs. parser.parse()

Re: Duplicate layers in TOC widget

MayJeff — Tue, 06 May 2014 14:28:42 GMT

Thank you for your suggestion and the info page. But I still see the error message.
http://jsfiddle.net/xZ5QQ/1/

Re: Duplicate layers in TOC widget

KenBuja — Tue, 06 May 2014 14:57:43 GMT

That Fiddle show a new error. However, if you switch back to 3.8, that error goes away.

Re: Duplicate layers in TOC widget

MayJeff — Tue, 06 May 2014 15:04:30 GMT

I realized that too. Only with version 3.9 got errors. Not sure why. Thank you.

Re: Duplicate layers in TOC widget

KenBuja — Tue, 06 May 2014 15:28:05 GMT

You may want to start a separate thread to get the attention of the API developers.

Re: Duplicate layers in TOC widget

NianweiLiu — Thu, 08 May 2014 17:18:19 GMT

That Fiddle show a new error. However, if you switch back to 3.8, that error goes away.

The problem for the code is around the event used to trigger the creation of the digit. The code used 'layer-add-result', which is an event that fired multiple times, thus the developer was actually trying to create many instances of TOC and would running into problems. Even developer code just called 'addLayer' once, the basemap add by API itself would trigger that event internally too.
Having something like "if (toc==null ) toc=new ..." might help, although it is really about make sure knowing when the code will be called.
Why 3.8 worked could be just how DOJO internally check div changed, may not even an ESRI thing.