esri javascript api symbolize layers

Question

I have a working application here: http://dola.colorado.gov/gis-cms/sites/default/files/html/census2000v2.html

I'm using the Javascript API with ArcGIS Online. I have a bunch of layers loaded and pre-symbolized in an AGOL 'Web Map'.

I'd like to be able to customize the symbology of each layer dynamically using javascript. I'd ideally like to use a renderer and be able to create a different symbology for each demographic variable.

I've run into a major brick wall. To be able to change the symbology, I need to be able to iterate through graphics in a feature set - yet I have no idea where to get a feature set object from. All the examples I see use 'Feature Layers' loaded through URLs.

Answer 1

I think first you need to get the layer from the webmap:

var featureLayer = mapObject.getLayer(layerName)

Then you can query the featurelayer, which will return a featureSet.

Here is an example:

var query = new esri.tasks.Query();
query.outFields = ["*"];

featureLayer.queryFeatures(query, function(featureSet) {
    //do something with the featureSet here!
});