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Feature layer hover

Description

This sample applies a definition expression to a feature layer to display a subset of the layer's graphics on the map. A FeatureLayer is a new layer type at 10 that inherit from the graphics layer and supports querying, selections,layer definitions and editing.

The feature layer constructor takes a url to an individual layer in a feature service and defines the mode and output fields. The mode determines how the features are returned to the client. In this case the application uses setDefinitionExpression to limit the results to a small set of features so mode is set to snapshot mode which returns all features to the client.

Because the feature layer inherits from graphics layers you can take advantage of graphics layer mouse events. This code listens for onMouseOver to display an InfoWindow when the mouse hovers over a graphic.

Code

<!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>Feature Layer - display results as an InfoWindow onHover</title>

    <link rel="stylesheet" href="https://js.arcgis.com/3.23/dijit/themes/tundra/tundra.css">
    <link rel="stylesheet" href="https://js.arcgis.com/3.23/esri/css/esri.css">
    <style>
      html, body, #mapDiv {
        padding:0;
        margin:0;
        height:100%;
      }
      #mapDiv {
        position: relative;
      }
      #info {
        background: #fff;
        box-shadow: 0 0 5px #888;
        left: 1em;
        padding: 0.5em;
        position: absolute;
        top: 1em;
        z-index: 40;
      }
    </style>

    <script src="https://js.arcgis.com/3.23/"></script>
    <script>
      var map, dialog;
      require([
        "esri/map", "esri/layers/FeatureLayer",
        "esri/symbols/SimpleFillSymbol", "esri/symbols/SimpleLineSymbol",
        "esri/renderers/SimpleRenderer", "esri/graphic", "esri/lang",
        "esri/Color", "dojo/number", "dojo/dom-style",
        "dijit/TooltipDialog", "dijit/popup", "dojo/domReady!"
      ], function(
        Map, FeatureLayer,
        SimpleFillSymbol, SimpleLineSymbol,
        SimpleRenderer, Graphic, esriLang,
        Color, number, domStyle,
        TooltipDialog, dijitPopup
      ) {
        map = new Map("mapDiv", {
          basemap: "streets",
          center: [-80.94, 33.646],
          zoom: 8,
          slider: false
        });

        var southCarolinaCounties = new FeatureLayer("https://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer/3", {
          mode: FeatureLayer.MODE_SNAPSHOT,
          outFields: ["NAME", "POP2000", "POP2007", "POP00_SQMI", "POP07_SQMI"]
        });
        southCarolinaCounties.setDefinitionExpression("STATE_NAME = 'South Carolina'");

        var symbol = new SimpleFillSymbol(
          SimpleFillSymbol.STYLE_SOLID,
          new SimpleLineSymbol(
            SimpleLineSymbol.STYLE_SOLID,
            new Color([255,255,255,0.35]),
            1
          ),
          new Color([125,125,125,0.35])
        );
        southCarolinaCounties.setRenderer(new SimpleRenderer(symbol));
        map.addLayer(southCarolinaCounties);

        map.infoWindow.resize(245,125);

        dialog = new TooltipDialog({
          id: "tooltipDialog",
          style: "position: absolute; width: 250px; font: normal normal normal 10pt Helvetica;z-index:100"
        });
        dialog.startup();

        var highlightSymbol = new SimpleFillSymbol(
          SimpleFillSymbol.STYLE_SOLID,
          new SimpleLineSymbol(
            SimpleLineSymbol.STYLE_SOLID,
            new Color([255,0,0]), 3
          ),
          new Color([125,125,125,0.35])
        );

        //close the dialog when the mouse leaves the highlight graphic
        map.on("load", function(){
          map.graphics.enableMouseEvents();
          map.graphics.on("mouse-out", closeDialog);

        });

        //listen for when the onMouseOver event fires on the countiesGraphicsLayer
        //when fired, create a new graphic with the geometry from the event.graphic and add it to the maps graphics layer
        southCarolinaCounties.on("mouse-over", function(evt){
          var t = "<b>${NAME}</b><hr><b>2000 Population: </b>${POP2000:NumberFormat}<br>"
            + "<b>2000 Population per Sq. Mi.: </b>${POP00_SQMI:NumberFormat}<br>"
            + "<b>2007 Population: </b>${POP2007:NumberFormat}<br>"
            + "<b>2007 Population per Sq. Mi.: </b>${POP07_SQMI:NumberFormat}";

          var content = esriLang.substitute(evt.graphic.attributes,t);
          var highlightGraphic = new Graphic(evt.graphic.geometry,highlightSymbol);
          map.graphics.add(highlightGraphic);

          dialog.setContent(content);

          domStyle.set(dialog.domNode, "opacity", 0.85);
          dijitPopup.open({
            popup: dialog,
            x: evt.pageX,
            y: evt.pageY
          });
        });

        function closeDialog() {
          map.graphics.clear();
          dijitPopup.close(dialog);
        }

      });
    </script>
  </head>
  <body class="tundra">
    <div id="mapDiv">
      <div id="info">
        Hover over a county in South Carolina to get more information.
      </div>
    </div>
  </body>
</html>