Flex4.6手机项目+arcgis api+瓦片地图

昨日看到一个牛人发的一篇博文，内容是利用arcgis api for flex读取自定义瓦片地图。我一想，能不能做Flex4.6手机项目读取本地地图缓存。经过两天的捣鼓，终于在我的爱机上显示预先切好的瓦片地图，欢喜。贴上代码：

MyLayer.as

package map
{
	import com.esri.ags.SpatialReference;
	import com.esri.ags.geometry.Extent;
	import com.esri.ags.geometry.MapPoint;
	import com.esri.ags.layers.TiledMapServiceLayer;
	import com.esri.ags.layers.supportClasses.LOD;
	import com.esri.ags.layers.supportClasses.TileInfo;
	
	import flash.filesystem.File;
	import flash.net.URLRequest;
	
	public class MyLayer extends TiledMapServiceLayer
	{
		public function PortlandTiledMapServiceLayer()
		{
			super();
			buildTileInfo(); // to create our hardcoded tileInfo  
			
			setLoaded(true); // Map will only use loaded layers 
		}
		private var _tileInfo:TileInfo = new TileInfo(); // see buildTileInfo()  
		
		public var filePath:File=File.documentsDirectory;
		private var _baseURL:String =filePath.url+"/BaseMap2/Layers/_alllayers/";//filePath.url为地图瓦片地图目录  
		
		//--------------------------------------------------------------------------  
		//  
		//  Overridden properties  
		//      fullExtent()  
		//      initialExtent()  
		//      spatialReference()  
		//      tileInfo()  
		//      units()  
		//  
		//--------------------------------------------------------------------------  
		
		
		//----------------------------------  
		//  fullExtent  
		//  - required to calculate the tiles to use  
		//----------------------------------  
		
		override public function get fullExtent():Extent  
		{  
			return new Extent(106.83278544323,19.5628611240401,117.999305409068,26.6235368076667,new SpatialReference(4326));  
		}  
		
		//----------------------------------  
		//  initialExtent  
		//  - needed if Map doesn't have an extent  
		//----------------------------------  
		
		override public function get initialExtent():Extent  
		{ 
			return new Extent(112.511576567339,21.9382229904827,114.171488565007,23.0936892549139,new SpatialReference(4326));  
		}  
		
		//----------------------------------  
		//  spatialReference  
		//  - needed if Map doesn't have a spatialReference  
		//----------------------------------  
		
		override public function get spatialReference():SpatialReference  
		{  
			return new SpatialReference(4326);  
		}  
		
		//----------------------------------  
		//  tileInfo  
		//----------------------------------  
		
		override public function get tileInfo():TileInfo  
		{  
			return _tileInfo;  
		}  
		
		//----------------------------------  
		//  units  
		//  - needed if Map doesn't have it set  
		//----------------------------------  
		
		override public function get units():String  
		{  
			return "esriDecimalDegrees";  
		}  
		
		//--------------------------------------------------------------------------  
		//  
		//  Overridden methods  
		//      getTileURL(level:Number,row:Number,col:Number):URLRequest  
		//  
		//--------------------------------------------------------------------------  
		
		override protected function getTileURL(level:Number,col:Number):URLRequest  
		{  
			  
			var url:String = _baseURL  
				+ "/L" + padString(String(level),2,"0")  
				+ "/R" + padString(row.toString(16),8,"0")  
				+ "/C" + padString(col.toString(16),"0") + ".png";  
			return new URLRequest(url);  
		}  
		
		//--------------------------------------------------------------------------  
		//  
		//  Private Methods  
		//  
		//--------------------------------------------------------------------------  
		
		private function buildTileInfo():void  
		{  
			_tileInfo.height = 256;  
			_tileInfo.width = 256;  
			_tileInfo.origin = new MapPoint(-400,400);  
			_tileInfo.spatialReference = new SpatialReference(4326);  
			_tileInfo.lods =  
				[  
					new LOD(0,0.0020766205141791532,1000000),new LOD(1,0.00062298615425374602,300000)
				];  
		}  
		
		private function padString(text:String,size:int,ch:String):String  
		{  
			while (text.length < size)  
			{  
				text = ch + text;  
			}  
			return text;  
		}  
	}  
	
}  

offline.mxml

<?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" 
			   applicationDPI="160" 
			   xmlns:ns="http://www.esri.com/2008/ags"
			   xmlns:map="map.*">
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
	</fx:Declarations>
	<ns:Map id="map" scaleBarVisible="false">
		<map:MyLayer id="virtualTiles" fadeInFrameCount="12"/>
	</ns:Map>
</s:Application>

这里需要注意一点的是在获取瓦片存放的目录这个地方。在调试的时候，用 public var filePath:File=File.documentsDirectory; private var _baseURL:String =filePath.nativePathl+"/BaseMap2/Layers/_alllayers/"; ?是可以访问到瓦片数据的，但是如果发布到android手机，地图就显示不出来了。但是如果把nativePath改成url就可以在android显示地图。