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javascript - 如何在 ArcGIS JS API 3.x 中通过鼠标单击事件选择多个要素

问题描述

我正在尝试通过使用“按住‘ctrl’按钮和鼠标单击事件”来选择要素图层中的多个要素。我正在使用 ArcGIS JS API 3.x。

我使用 FeatureCollection 创建了美国国界 FeatureLayer，并且能够在地图上显示图层。用户希望在按住“ctrl”或“alt”键的同时通过鼠标单击来选择多个状态。

var featureLayer = new esri.layers.FeatureLayer(featureCollection, {
    id: stateLayer,
    opacity: 0.30,
    visible: true,
    infoTemplate: infoTemplate
});
g_esri.map.addLayer(featureLayer);
featureLayer.on("click", onBoundaryClick);

function onBoundaryClick(evt) {
    var g = evt.graphic;
    g_esri.map.infoWindow.setContent(g.getContent());
    g_esri.map.infoWindow.show(evt.screenPoint, g_esri.map.getInfoWindowAnchor(evt.screenPoint));
    formatInfotemplate(false, g);
}

我尝试关注以下一些链接，

一个。使用图形选择多个功能

湾。通过鼠标单击选择多个功能

却无法通过，

标签： javascriptmouseeventarcgisesriarcgis-js-api

解决方案

我已经很久没有使用 3.xx API 了。无论如何，也许我为你制作的这个例子可以帮助你。这个想法基本上是听特征层上的点击事件来捕捉选定的图形，然后添加到选定的集合中。添加时只需检查是否按下了所需的键。

<!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>Labeling features client-side</title>
    <link rel="stylesheet" href="https://js.arcgis.com/3.35/esri/css/esri.css">
    <style>
      html, body, #map {
        height: 100%; width: 100%; margin: 0; padding: 0; 
      }
    </style>

   <script src="https://js.arcgis.com/3.35/"></script>
    <script>
      var map;
    
      require([
        "esri/map", 
        "esri/geometry/Extent",
        "esri/layers/FeatureLayer",
        "esri/layers/GraphicsLayer",
        "esri/symbols/SimpleLineSymbol",
        "esri/symbols/SimpleFillSymbol",
        "esri/renderers/SimpleRenderer",
        "esri/Color",
         
        "dojo/domReady!"
      ], function(Map, Extent, FeatureLayer, GraphicsLayer,
                  SimpleLineSymbol, SimpleFillSymbol, 
                  SimpleRenderer, Color) 
      {
        const bbox = new Extent({"xmin": -1940058, "ymin": -814715, "xmax": 1683105, "ymax": 1446096, "spatialReference": {"wkid": 102003}});
      
        const map = new Map("map", {
          extent: bbox   
        });


        const statesUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/3";
        const states = new FeatureLayer(statesUrl, {
          id: "states",
          outFields: ["*"]
        });

        map.addLayer(states);

        const color = new Color("#00ffff");
        const line = new SimpleLineSymbol("solid", color, 1.5);
        const symbol = new SimpleFillSymbol("solid", line, null);
        const renderer = new SimpleRenderer(symbol);
        const selected = new GraphicsLayer();
        selected.setRenderer(renderer);
        map.addLayer(selected);

        let ctrl = false;
        let shift = false;

        map.on("key-down", function (evt) {
          if (evt.key === "Control") {
            ctrl = true;
          } else if (evt.key === "Shift") {
            shift = true;
          }
        });

        map.on("key-up", function (evt) {
          if (evt.key === "Control") {
            ctrl = false;
          } else if (evt.key === "Shift") {
            shift = false;
          }
        });

        states.on("click", function (evt) {
          if (!ctrl && !shift) {
            selected.clear();
          }
          selected.add(evt.graphic.clone());
          console.log(`Selected: ${selected.graphics.length}`);
        });
    
      });
    </script>
  </head>
  <body>
    <div id="map"></div>
  </body>
</html>

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