Symbol for Graphic object is always undefined when added to layer

SchuylerMetcalf · ‎03-18-2015

When accessing a Graphic object, the Symbol attribute returns undefined, even though a symbol is drawn on the map. After changing the symbol using the graphic.setSymbol() method, it is no longer undefined. Here is slightly modified code from this sample for a CSV layer:

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no"/>
    <title>Simple Map</title>
    <link rel="stylesheet" href="http://js.arcgis.com/3.13/esri/css/esri.css">
    <style>
      html, body, #map {
        height: 100%;
        width: 100%;
        margin: 0;
        padding: 0;
      }
      body {
        background-color: #FFF;
        overflow: hidden;
        font-family: "Trebuchet MS";
      }
    </style>
    <script src="http://js.arcgis.com/3.13/"></script>
    <script>
      var map, csv;


      require([
        "esri/map", 
        "esri/layers/CSVLayer",
        "esri/Color",
        "esri/symbols/SimpleMarkerSymbol",
        "esri/renderers/SimpleRenderer",
        "esri/InfoTemplate",
        "esri/urlUtils",
        "dojo/on",
        "dojo/domReady!" 
        
      ], function(
        Map, CSVLayer, Color, SimpleMarkerSymbol, SimpleRenderer, InfoTemplate, urlUtils, on
      ) {
        urlUtils.addProxyRule({
          proxyUrl: "/proxy/",
          urlPrefix: "earthquake.usgs.gov"
        });
        map = new Map("map", {
          basemap: "gray",
          center: [ -60, -10 ],
          zoom: 4 
        });
        csv = new CSVLayer("http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_week.csv", {
          copyright: "USGS.gov"
        });
        var orangeRed = new Color([238, 69, 0, 0.5]); // hex is #ff4500
        var marker = new SimpleMarkerSymbol("solid", 15, null, orangeRed);
        var renderer = new SimpleRenderer(marker);
        csv.setRenderer(renderer);
        var template = new InfoTemplate("${type}", "${place}");
        csv.setInfoTemplate(template);
        map.addLayer(csv);


        on(map.getLayer(map.graphicsLayerIds[0]), 'click', function(event){
          console.log("Before Changing: ", event.graphic.symbol)
          event.graphic.setSymbol(new SimpleMarkerSymbol("solid", 30, null, new Color([238, 69, 0, 0.5])))
          console.log("After changing: ", event.graphic.symbol)
        });
      });
    </script>
  </head>


  <body>
    <div id="map"></div>
  </body>
</html>

Am I doing something dumb, or is this a bug? I would like to access the symbol for a given graphic before a user interacts with it

KellyHutchins · ‎03-18-2015

Since you are using a renderer to symbolize your layer you'll need to use the renderer's getSymbol method to get the symbol for the selected graphic. Here's some code showing how this works:

  
        on(map.getLayer(map.graphicsLayerIds[0]), 'click', function(event){  
          var symbol = renderer.getSymbol(event.graphic);
          console.log("Before Changing: ", symbol)  
          event.graphic.setSymbol(new SimpleMarkerSymbol("solid", 30, null, new Color([238, 69, 0, 0.5])))  
          console.log("After changing: ", event.graphic.symbol)  
        });