ArcGis for Flex---Flex4.0之使用DropdownList控件来切换GIS地图

毕业设计要用Flex做一个地图模块，使用ArcGIS API For Flex。今天首先做一个地图显示和切换，首先看运行效果截图：

主要就是DropdownList控件的使用，以及如何在Flex中使用ArcGIS的控件来显示地图。下面贴上代码：

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
			   xmlns:s="library://ns.adobe.com/flex/spark"
			   xmlns:mx="library://ns.adobe.com/flex/mx"
			   xmlns:esri="http://www.esri.com/2008/ags"
			   minWidth="1000" minHeight="600">
	
	<fx:Script>
		<![CDATA[
			import mx.collections.ArrayList;
			import mx.collections.XMLListCollection;
			import mx.controls.Alert;
			import mx.events.IndexChangedEvent;
			
			import spark.events.IndexChangeEvent;
			
			private var showMapName:String;
			
			private function mapSelectorChangeHandler(event:IndexChangeEvent):void
			{
				showMapName="http://service:8399/arcgis/rest/services/"+mapSelector.selectedItem.value+"/MapServer/"
//				Alert.show(showMapName);
				mapServiceLayer.url=showMapName;
			}
		]]>
	</fx:Script>

	
		
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
		<s:XMLListCollection id="mapNames">
			<fx:XMLList xmlns="">
				<map>
					<name>856农场</name>
					<value>856</value>
				</map>
				<map>
					<name>双峰农场</name>
					<value>ShuangFeng</value>
				</map>
			</fx:XMLList>
		</s:XMLListCollection>
	</fx:Declarations>
	<esri:Map id="mapView" x="144" y="41" width="800" height="550">
		<esri:ArcGISDynamicMapServiceLayer id="mapServiceLayer" />
	</esri:Map>
	<s:DropDownList id="mapSelector" left="5" top="5" height="20" fontSize="13" fontWeight="normal"
					dataProvider="{mapNames}" labelField="name" change="mapSelectorChangeHandler(event)" prompt="地图切换">
	</s:DropDownList>
</s:Application>