[HELP] Create custom FeatureLayer?

Question

Hi,

We are considering using ArcGIS JavaScript in our Windows 8.1 modern application.

The main scenario is simple: just display some "data layers" on the map.

Seems like FeatureLayer can fulfill our requirements. We did try CSVLayer and it worked.

However, our data source is a Web Service that returns JSON (an OData service) so CSV is not a convenient format for us.

So naturally the questions are...

1. What is alternative for our scenario? I see there are only CSV/StreamLayer, but we need to consume JSON.

2. Do we need to create our custom FeatureLayer (in our case, probably ODataJSONLayer) ?

2. Is there any tutorial, sample or learning material regarding to create a custom FeatureLayer?

3. Does it require "big" effort to do so or it is a relatively easy task?

Thank!

devcig · Answer

Thanks for your quick reply, Riyas. One thing I found just now was, the basic map viewer seems reads layers information from the response.ItemData.operationallayers, so to make my layers appear in the legend and layers picker, I also need add according infomation to the response.ItemData.operationallayers object...

Now I found it's not easy to generated a qualified "operational layer" object, my code is like below:

response.itemInfo.itemData.operationalLayers.push({
   id : "testLayer",
   title : "Test Layer",
   visilbility: true,
   layer : gl,
   url : "",
   opacity : 0.75
  });

It misses some properties compare with the "operational layer" object in server response, e.g. the resourceInfo propety. So there were exceptions, in debugger it shows:

"TypeError: Unable to get property 'on' of undefined or null reference
   at k (http://js.arcgis.com/3.10/init.js:213:276)
   at _layerEvent (http://localhost/ArcGISMeshupApp/js/TableOfContents.js:223:13)
   at _setLayerEvents (http://localhost/ArcGISMeshupApp/js/TableOfContents.js:289:25)
   at _createList (http://localhost/ArcGISMeshupApp/js/TableOfContents.js:189:17)
   at _init (http://localhost/ArcGISMeshupApp/js/TableOfContents.js:352:13)
   at startup (http://localhost/ArcGISMeshupApp/js/TableOfContents.js:59:17)
   at _addLayers (http://localhost/ArcGISMeshupApp/js/main.js:399:21)
   at Anonymous function (http://localhost/ArcGISMeshupApp/js/main.js:154:25)
   at Anonymous function (http://js.arcgis.com/3.10/init.js:174:14)
   at k (http://js.arcgis.com/3.10/init.js:195:425)"

I'm not sure whether there are any official means to generate this "operational layer" object? Riyas Deen‌

RiyasDeen · Answer

Yes dev,

response.map is an esri/map object and you should be able to inject the code for your custom layer in the same way as i have done.

devcig · Answer

Thanks Riyas. The problem with the first solution is, the map is not from us, and we are merely trying to add custom layers on top of it. So I guess I would take you solution #2. Just to confirm, according to your code above, the response from ArcGIS online/ArcGIS server portal contains the esri/map object, so I can inject my custom layers at that point right?