描述
本例展示如何配置查询任务为示例的工作流程:
1.用户单击一个要素来加亮显示。
2.用户再一次单击要素来查看属性信息的 InfoWindow。
本例查询USA州，因此ESRI_StateCityHighway_USA的州图层被传给QueryTask构造函数。
第一次鼠标单击通过下面的事件监听器捕获:
dojo.connect(map, "onClick", executeQueryTask);
发生单击时，executeQueryTask函数被调用去执行查询，然后showResults函数增加图形。
当用户单击高亮的图形时，第二次鼠标单击默认被捕获。为了格式化信息窗口，应用使用showResults函数调用graphic.setInfoTemplate应用的InfoTemplate。
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=7" />
<title>QueryTask with geometry, results as an InfoWindow</title>
<link rel="stylesheet" type="text/css"
href="http://serverapi.arcgisonline.com/jsapi/arcgis/1.6/js/dojo/dijit/themes/tundra/tundra.css" rel="external nofollow" >
<script type="text/javascript" src="http://serverapi.arcgisonline.com/jsapi/arcgis/?v=1.6"></script>
<script type="text/javascript" language="Javascript">
dojo.require("esri.map");
dojo.require("esri.tasks.query"); var map, queryTask, query;
var symbol, infoTemplate; function init() {
//创建地图
map = new esri.Map("mapDiv"); //创建并添加动态层
var layer = new esri.layers.ArcGISDynamicMapServiceLayer("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer");
map.addLayer(layer); //监听click事件，当用户点击地图时执行executeQueryTask方法
dojo.connect(map, "onClick", executeQueryTask); //建立查询任务
queryTask = new esri.tasks.QueryTask("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer/1"); //监听onComplete事件的处理结果，使用queryTask.execute方法回调
//dojo.connect(queryTask, "onComplete", showResults); //建立查询过滤器
query = new esri.tasks.Query();
query.returnGeometry = true;
query.outFields = ["STATE_NAME",
"STATE_FIPS", "STATE_ABBR", "HYPERLINK", "AREA"]; //在信息窗口创建infoTemplate
//${属性名}将取代目前的功能和属性值
infoTemplate = new esri.InfoTemplate("${STATE_NAME}", "State Fips:${STATE_FIPS}<br />Abbreviation: ${STATE_ABBR}<br />Area: ${AREA}"); symbol = new esri.symbol.SimpleFillSymbol
(esri.symbol.SimpleFillSymbol.STYLE_SOLID,
new esri.symbol.SimpleLineSymbol(esri.symbol.SimpleLineSymbol.STYLE_DASHDOT,
new dojo.Color([255,0,0]), 2), new dojo.Color([255,255,0,0.5]));
} function executeQueryTask(evt) {
//用户点击onClick事件返回地图上EVT点.
//包含在MapPoint(esri.geometry.point)和screenPoint(pixel像素点).
//设置查询几何等于evt.mapPoint
query.geometry = evt.mapPoint; //执行任务和完成showResults
queryTask.execute(query, showResults);
} function showResults(featureSet) {
//删除地图上所有的图形层
map.graphics.clear(); //QueryTask返回featureSet类型.通过featureSet的循环把他们添加到信息窗口
for (var i=0, il=featureSet.features.length; i<il; i++) {
//从featureSet中得到当前实例.
//从当前实例赋值给graphic
var graphic = featureSet.features[0];
graphic.setSymbol(symbol); //设置图形的infoTemplate.
graphic.setInfoTemplate(infoTemplate); //添加当前这个图形到地图图层中
map.graphics.add(graphic);
}
} dojo.addOnLoad(init);
</script>
</head>
<body class="tundra">
Click on a State to get more info. When State is highlighted, click State again to get infoWindow.
<div id="map" style="width:600px; height:600px; border:1px solid #000;"></div>
</body>
</html>
