Flex動態設定Button中的icon指向外網圖片源

IconUtility.as

package
{
import flash.display.BitmapData;
import flash.display.Loader;
import flash.display.LoaderInfo;
import flash.events.Event;
import flash.geom.Matrix;
import flash.net.URLRequest;
import flash.system.LoaderContext;
import flash.utils.Dictionary;    
import mx.containers.accordionClasses.AccordionHeader;
import mx.controls.tabBarClasses.Tab;
import mx.core.BitmapAsset;
import mx.core.UIComponent;

public class IconUtility extends BitmapAsset
    {
private static var dictionary:Dictionary;        
public static function getClass( target:UIComponent, source:String, width:Number = NaN, height:Number = NaN ):Class 
        {
if(!dictionary) 
            {
                dictionary = new Dictionary(false);
            }
//if(source is String) 
//{
                var loader:Loader = new Loader();
                loader.load(new URLRequest(source as String), new LoaderContext(true));
//source = loader;
//}
            dictionary[target] = { source:loader, width:width, height:height };
return IconUtility;
        }

public function IconUtility():void 
        {
            addEventListener(Event.ADDED, addedHandler, false, 0, true)
        }

private function addedHandler(event:Event):void 
        {
if(parent) 
            {
if(parent is AccordionHeader) 
                {
                    var header:AccordionHeader = parent as AccordionHeader;
                    getData(header.data);
                } 
else if(parent is Tab) 
                {
                    var tab:Tab = parent as Tab;
                    getData(tab.data);
                } 
else 
                {
                    getData(parent);
                }
            }
        }

private function getData(object:Object):void 
        {
            var data:Object = dictionary[object];
if(data) 
            {
                var source:Object = data.source;
if(data.width > 0 && data.height > 0) 
                {
                    bitmapData = new BitmapData(data.width, data.height, true, 0x00FFFFFF);
                }
if(source is Loader) 
                {
                    var loader:Loader = source as Loader;
if(!loader.content) 
                    {
                        loader.contentLoaderInfo.addEventListener(Event.COMPLETE, completeHandler, false, 0, true);
                    } 
else 
                    {
                        displayLoader(loader);
                    }
                }
            }
        }

private function displayLoader( loader:Loader ):void 
        {
if(!bitmapData) 
            {
                bitmapData = new BitmapData(loader.content.width, loader.content.height, true, 0x00FFFFFF);
            }

            bitmapData.draw(loader, new Matrix(bitmapData.width/loader.width, 0, 0, bitmapData.height/loader.height, 0, 0));

if(parent is UIComponent) 
            {
                var component:UIComponent = parent as UIComponent;
                component.invalidateSize();
            }
        }

private function completeHandler(event:Event):void 
        {
if(event && event.target && event.target is LoaderInfo) 
            {
                displayLoader(event.target.loader as Loader);
            }
        }
    }
}

 

main.mxml

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
<mx:Script>
<![CDATA[
        import com.IconUtility;
        public function open():void
        { 
            navigateToURL(new URLRequest("http://hi.baidu.com/woaidelphi/"), "_blank"); 
        }   
]]>
</mx:Script>
<mx:Button id="button" label="Button" 
        icon="{IconUtility.getClass(button, 'http://hiphotos.baidu.com/woaidelphi/abpic/item/ace9cd3836b88206b9998fe9.jpg')}" x="488" y="233" width="278" height="107"
        click="open()"/>
</mx:Application>