ArcGIS API for JavaScript 4.2学习笔记[24] 【IdentifyTask类】的使用（结合IdentifyParameters类）（第七章完结）

结果演示

<script>
require([
"esri/Map",
"esri/views/MapView",
"esri/layers/TileLayer",
"esri/tasks/IdentifyTask",
"esri/tasks/support/IdentifyParameters",
"dojo/_base/array",
"dojo/on",
"dojo/dom",
"dojo/domReady!"
], function(
Map, MapView, TileLayer,
IdentifyTask, IdentifyParameters,
arrayUtils, on, dom
) {

var identifyTask, params;

// URL to the map service where the identify will be performed
var soilURL =
"https://services.arcgisonline.com/arcgis/rest/services/Specialty/Soil_Survey_Map/MapServer";

// Add the map service as a TileLayer for fast rendering
// Tile layers are composed of non-interactive images. For that reason we'll
// use IdentifyTask to query the service to add interactivity to the app
var parcelsLyr = new TileLayer({
url: soilURL,
opacity: 0.85
});

var map = new Map({
basemap: "osm"
});
map.add(parcelsLyr);

var view = new MapView({
map: map,
container: "viewDiv",
center: [-120.174, 47.255],
zoom: 7
});

view.then(function() {
// executeIdentifyTask() is called each time the view is clicked
on(view, "click", executeIdentifyTask);

// Create identify task for the specified map service
identifyTask = new IdentifyTask(soilURL);

// Set the parameters for the Identify
params = new IdentifyParameters();
params.tolerance = 3;
params.layerIds = [0, 1, 2];
params.layerOption = "top";
params.width = view.width;
params.height = view.height;
});

// Executes each time the view is clicked
function executeIdentifyTask(event) {
// Set the geometry to the location of the view click
params.geometry = event.mapPoint;
params.mapExtent = view.extent;
dom.byId("viewDiv").style.cursor = "wait";

// This function returns a promise that resolves to an array of features
// A custom popupTemplate is set for each feature based on the layer it
// originates from
identifyTask.execute(params).then(function(response) {

var results = response.results;

return arrayUtils.map(results, function(result) {

var feature = result.feature;
var layerName = result.layerName;

feature.attributes.layerName = layerName;
if (layerName === 'Soil Survey Geographic') {
feature.popupTemplate = { // autocasts as new PopupTemplate()
title: "{Map Unit Name}",
content: "<b>Dominant order:</b> {Dominant Order} ({Dom. Cond. Order %}%)" +
"<br><b>Dominant sub-order:</b> {Dominant Sub-Order} ({Dom. Cond. Suborder %}%)" +
"<br><b>Dominant Drainage Class:</b> {Dom. Cond. Drainage Class} ({Dom. Cond. Drainage Class %}%)" +
"<br><b>Farmland Class:</b> {Farmland Class}"
};
}
else if (layerName === 'State Soil Geographic') {
feature.popupTemplate = { // autocasts as new PopupTemplate()
title: "{Map Unit Name}",
content: "<b>Dominant order:</b> {Dominant Order} ({Dominant %}%)" +
"<br><b>Dominant sub-order:</b> {Dominant Sub-Order} ({Dominant Sub-Order %}%)"
};
}
else if (layerName === 'Global Soil Regions') {
feature.popupTemplate = { // autocasts as new PopupTemplate()
title: layerName,
content: "<b>Dominant order:</b> {Dominant Order}" +
"<br><b>Dominant sub-order:</b> {Dominant Sub-Order}"
};
}
return feature;
});
}).then(showPopup); // Send the array of features to showPopup()

// Shows the results of the Identify in a popup once the promise is resolved
function showPopup(response) {
if (response.length > 0) {
view.popup.open({
features: response,
location: event.mapPoint
});
}
dom.byId("viewDiv").style.cursor = "auto";
}
}
});
</script>