4.6版本api的FeatureLayer中有提供 labelsVisible 和 labelingInfo 两个属性，设置这两个属性可以实现显示将属性中某个字段作为标注。但是这两个属性只针对三维SceneView有效。如下图截图所示。
那么在二维中要实现FeatureLayer添加标注的功能，只能自己在FeatureLayer要素中的某个位置，添加一个TextSymbol的Point要素。结合上一篇讲到的 “获取FeatureLayer中的graphics集合”，我们可以通过如下的方法进行实现
源码：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no">
<title>FeatureLayer - 4.7</title>
<style>
html, body, #viewDiv {
padding: 0;
margin: 0;
height: 100%;
width: 100%;
}
</style>
<link rel="stylesheet" href="https://js.arcgis.com/4.7/esri/css/main.css">
<script src="https://js.arcgis.com/4.7/"></script>
</head>
<body>
<div id="viewDiv"></div>
<script type="text/javascript">
require([
"esri/Map",
"esri/views/MapView",
"esri/layers/FeatureLayer",
"esri/layers/GraphicsLayer",
"dojo/domReady!"
],
function (Map, MapView, FeatureLayer, GraphicsLayer) {
let map = new Map({
basemap: "satellite"
}); let view = new MapView({
container: "viewDiv",
map: map,
center: [-73.950, 40.702],
zoom: 12,
padding: {
right: 300
}
}); let featureLayer1 = new FeatureLayer({
url: "https://services.arcgis.com/V6ZHFr6zdgNZuVG0/ArcGIS/rest/services/NYCDemographics1/FeatureServer/0",
outFields: ["OBJECTID_1"]
});
let nameGraphicsLayer = new GraphicsLayer();
map.add(featureLayer1);
map.add(nameGraphicsLayer); view.when(function () {
//地图刚初始化时获取graphics集合，需要监控featureLayer的updating状态完成后才能获取到
view.whenLayerView(featureLayer1).then(function (lyrView) {
lyrView.watch("updating", function(){
lyrView.queryFeatures().then(function (results) {
//console.log(results);
results.forEach(function (g) {
nameGraphicsLayer.add({
geometry: {
type: "point",
latitude: g.geometry.centroid.latitude,
longitude: g.geometry.centroid.longitude
},
symbol: {
type: "text",
color: "white",
text: g.attributes["OBJECTID_1"],
font: {
size: 14,
family: "sans-serif",
weight: "bolder"
}
}
});
});
});
});
});
});
}
);
</script>
</body>
</html>
效果图：
