ArcGIS For Flex學習之Mapping---Select and zoom

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Tips：這個例子說明如何在圖層中選擇或反選幾何對象，當點擊地圖時，觸發mapClick事件，啟用QueryTask，這裡的Query中的query.geometry = event.mapPoint;利用滑鼠點擊的點來尋找包括該選擇點的Polygon，然後將查詢到的幾何要素添加到GraphicsLayer中並放大一個層級；同時，再次點擊選擇的要素時，觸發unselectGraphic事件，並從GraphicsLayer中移除該要素。具體及代碼如下：

  1 <?xml version="1.0" encoding="utf-8"?>  2 <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"  3                xmlns:s="library://ns.adobe.com/flex/spark"  4                xmlns:esri="http://www.esri.com/2008/ags"  5                pageTitle="Select and Zoom">  6       7     <fx:Script>  8         <![CDATA[  9             import com.esri.ags.Graphic; 10             import com.esri.ags.events.MapMouseEvent; 11             import com.esri.ags.events.QueryEvent; 12             import com.esri.ags.geometry.Extent; 13             import com.esri.ags.utils.GraphicUtil; 14              15             import mx.collections.ArrayCollection; 16             import mx.collections.ArrayList; 17              18             private var mapClickToggler:Boolean = true; 19              20             private function mapClickHandler(event:MapMouseEvent):void 21             { 22                 if (mapClickToggler) 23                 { 24                     query.geometry = event.mapPoint; 25                     queryTask.execute(query); 26                 } 27             } 28              29             private function executeCompleteHandler(event:QueryEvent):void 30             { 31                 for each (var myGraphic:Graphic in event.featureSet.features) 32                 { 33                     myGraphic.symbol = mySymbol; 34                     myGraphic.addEventListener(MouseEvent.CLICK, unselectGraphic); 35 //                    myGraphic.addEventListener(MouseEvent.ROLL_OVER, toggleMapClick); 36 //                    myGraphic.addEventListener(MouseEvent.ROLL_OUT, toggleMapClick); 37                     myGraphicsLayer.add(myGraphic); 38                 } 39                 zoomToGraphics(); 40             } 41              42             private function zoomToGraphics():void 43             { 44                 var graphicProvider:ArrayCollection = myGraphicsLayer.graphicProvider as ArrayCollection; 45                 var graphicsExtent:Extent = GraphicUtil.getGraphicsExtent(graphicProvider.toArray()); 46                  47                 if (graphicsExtent) 48                 { 49                     myMap.extent = graphicsExtent; 50                      51                     // make sure the whole extent is visible 52                     if (!myMap.extent.contains(graphicsExtent)) 53                     { 54                         myMap.level--; 55                     } 56                 } 57             } 58              59             private function unselectGraphic(event:MouseEvent):void 60             { 61                 myGraphicsLayer.remove(event.currentTarget as Graphic); 62                 zoomToGraphics(); 63             } 64              65             private function toggleMapClick(event:MouseEvent):void 66             { 67                 mapClickToggler = !mapClickToggler; 68             } 69         ]]> 70     </fx:Script> 71      72     <fx:Declarations> 73         <esri:QueryTask id="queryTask" 74                         executeComplete="executeCompleteHandler(event)" 75                         url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer/5" 76                         useAMF="false"/> 77         <esri:Query id="query" 78                     outSpatialReference="{myMap.spatialReference}" 79                     returnGeometry="true"/> 80         <esri:SimpleFillSymbol id="mySymbol" 81                                alpha="0.7" 82                                color="#D3D1D1" 83                                > 84         </esri:SimpleFillSymbol> 85     </fx:Declarations> 86      87     <s:controlBarContent> 88         <s:RichText width="100%"> 89             This sample demonstrates how to select or deselect a graphic 90             in a graphics layer.  This is accomplished by using a QueryTask to 91             add features to a graphics layer, or remove graphics from the graphics 92             layer by clicking on that graphic.  The GraphicUtil class is also used 93             in this sample to get the extent of all the graphics in the graphics 94             layer and adjust the map extent and scale based upon if the features 95             are contained within the current extent. 96             Click on a state to select or unselect it.  The map will zoom to current selection. 97         </s:RichText> 98     </s:controlBarContent> 99     100     <esri:Map id="myMap" mapClick="mapClickHandler(event)">101         <esri:extent>102             <esri:Extent xmin="-13901000" ymin="3292000" xmax="-8812000" ymax="6154000">103                 <esri:SpatialReference wkid="102100"/>104             </esri:Extent>105         </esri:extent>106         <esri:ArcGISTiledMapServiceLayer url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer"/>107         <esri:ArcGISDynamicMapServiceLayer url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer" visibleLayers="{new ArrayList([5])}"/>108         <esri:GraphicsLayer id="myGraphicsLayer"/>109     </esri:Map>110     111 </s:Application>

 

ArcGIS For Flex學習之Mapping---Select and zoom