arcgis api for javascrpit extent()与execute()

来源：互联网发布：淘宝神笔下载编辑：程序博客网时间：2024/05/29 12:43

按道理来说，extent与execute应该不会相互影响。

今天就碰上了一个奇怪的问题，如果把extent注释掉，execute就不好用了……

源代码：

<!DOCTYPE html><html><head>    <meta charset="UTF-8">    <title>Resizable Map</title>    <link rel="stylesheet" type="text/css" href="http://serverapi.arcgisonline.com/jsapi/arcgis/2.0/js/dojo/dijit/themes/tundra/tundra.css"/>    <script type="text/javascript" src="http://serverapi.arcgisonline.com/jsapi/arcgis?v=2.0"></script>    <script type="text/javascript" src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.min.js"></script>    <script>        //地图div的宽高        var wid;        var hei;        var map;        var graphicLayer;        dojo.require("esri.map");        dojo.require("esri.toolbars.navigation");        dojo.require("esri.tasks.query");        function init(){            var initExtent = new esri.geometry.Extent({"xmin": 76252, "ymin": 295635, "xmax": 135783, "ymax": 305322, "spatialReference": { "wkid": 106000 }  });            map = new esri.Map("map",{//加载地图                logo:false,//不显示logo                extent: initExtent            });            var myTiledMapServiceLayer = new esri.layers.ArcGISTiledMapServiceLayer("http://192.168.0.181/ArcGIS/rest/services/GISBaseMap/MapServer");            map.addLayer(myTiledMapServiceLayer);            var myTiledMapServiceLayer1 = new esri.layers.ArcGISTiledMapServiceLayer("http://192.168.0.181/ArcGIS/rest/services/ModelPipe_BaseMap/MapServer");            map.addLayer(myTiledMapServiceLayer1);        }        window.onload=function(){            /*事件监听，div宽高变化*/            /*首先获取div当前宽高，然后每隔一秒钟获取一次div当前宽高，然后同上一次获取到的宽高进行比较，如果改变，则触发事件，重新加载地图*/            wid=$('#map').width();            hei=$('#map').height();            setInterval("changed()",100);        }        //监听地图宽高改变事件        function changed(){            var wid1=$('#map').width();            var hei1=$('#map').height();            if(wid1!=wid || hei1!=hei){                wid=wid1;                hei=hei1;                window.map.resize();            }        }        //添加点        function mapGraphicAdd(x,y){            if(graphicLayer!=null){                graphicLayer.clear();            }            graphicLayer = new esri.layers.GraphicsLayer();            map.addLayer(graphicLayer);            var point = new esri.geometry.Point(x,y);            var infoTemplate = new esri.InfoTemplate("point","<div style='background-color:red;border:1px solid red'>this is the new point</div>");            var simpleMarkerSymbol = new esri.symbol.SimpleMarkerSymbol();            var graphic = new esri.Graphic(point,simpleMarkerSymbol);            graphicLayer.add(graphic.setInfoTemplate(infoTemplate));        }        //清除点        function mapClear(){            graphicLayer.clear();        }        dojo.addOnLoad(init);        //获取阀门详细信息        var fs;        function getfamen(ii) {                        var cityQueryTask = new esri.tasks.QueryTask("http://192.168.0.181/ArcGIS/rest/services/ModelPipe_BaseMap/MapServer/3");            var cityQuery = new esri.tasks.Query();            cityQuery.outFields = ["*"];            cityQuery.returnGeometry = true;            cityQuery.outSpatialReference = map.spatialReference;            cityQuery.where = "ElementId =" + ii;            cityQueryTask.execute(cityQuery, addCityFeatureSetToMap);        }        function addCityFeatureSetToMap(featureSet) {            var symbol = new esri.symbol.SimpleMarkerSymbol();            symbol.setColor(new dojo.Color([0, 0, 255]));            var infoTemplate = new esri.InfoTemplate("阀门信息", "${*}");            fs = featureSet;            dojo.forEach(featureSet.features, function (feature) {                graphicLayer.add(feature.setSymbol(symbol).setInfoTemplate(infoTemplate));            });        }    </script></head><body><div id="map" style="width: 50%;height: 50%;border: 1px solid red"></div><div onclick="mapGraphicAdd(95353.359,304542.613)">添加</div><div onclick="getfamen('275139')">添加</div><div onclick="mapClear()">清除</div></body></html>

这里，首先点击第一个添加，向地图上加入一个x:95353.359,y:304542.613的标记，然后点击第二个添加，从http://192.168.0.181/ArcGIS/rest/services/ModelPipe_BaseMap/MapServer/3 图层中获取第二个点ElementId=275139的坐标，添加到地图上。

问题是，如果我将代码中 extent: initExtent 这一行注释掉的话，点击第二个添加就不会有第二个点添加到地图上了。代码会运行到

cityQueryTask.execute(cityQuery, addCityFeatureSetToMap); 这一行。

设置extent 的目的是为了初始化地图在首次加载时候的位置，而 execute()是arcgis的图层要素查询的功能。这两个按道理来讲是没有太大联系的。难道是因为没有设置wkid，导致graphicLayer找不到点吗？

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