Flex與後臺互動的幾種方法詳解

1.FlashVars（單向傳遞）

A.傳遞：在<embed 中設定 FlashVars=”name1=value1&name2=value2”
B.接受:在as中寫入 var value1=application.parameters.name1 即可

2.HttpService

<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="initializeHandler(event)"> 
<mx:Script> 
<![CDATA[ 
private function initializeHandler(event:Event):void { 
countriesService.send(); 
} 
private function changeHandler(event:Event):void { 
statesService.send(); 
} 
]]> 
</mx:Script> 
<!-- 載入純靜態的xml資料 --> 
<mx:HTTPService id="countriesService" url="http://www.rightactionscript.com/states/xml/countries.xml" /> 
<!-- 載入由php生成的xml資料 --> 
<mx:HTTPService id="statesService" url="http://www.rightactionscript.com/states/xml/states.php"> 
<!-- 以下標籤就是要傳送到服務端的資料了,可以這樣理解:有一個名為country的變數,它的值為花括號{}裡的內容 --> 
<mx:request> 
<country>{country.value}</country> 
</mx:request> 
</mx:HTTPService> 
<mx:VBox> 
<!-- 此控制元件的資料由第一個<mx:HTTPService/>控制元件接收的內容提供,並且由這個ComboBox控制著第二個ComboBox所要顯示的內容 -->
<mx:ComboBox id="country" dataProvider="{countriesService.lastResult.countries.country}" 
change="changeHandler(event)" /> 
<!-- 下面的ComboBox已經繫結了{statesService.lastResult.states.state},隨它的資料改變而改變 --> 
<mx:ComboBox dataProvider="{statesService.lastResult.states.state}" /> 
</mx:VBox> 
</mx:Application> 

3.URLLoader

<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="initializeHandler(event)"> 
<mx:Script> 
<![CDATA[ 
private var _countriesService:URLLoader; 
private var _statesService:URLLoader; 
private function initializeHandler(event:Event):void { 
_countriesService = new URLLoader(); 
_countriesService.addEventListener(Event.COMPLETE, countriesCompleteHandler); 
_countriesService.load(new URLRequest("http://www.rightactionscript.com/states/xml/countries.xml")); 
_statesService = new URLLoader(); 
_statesService.addEventListener(Event.COMPLETE, statesCompleteHandler); 
XML.ignoreWhitespace = true; 
} 
private function countriesCompleteHandler(event:Event):void { 
var xml:XML = new XML(_countriesService.data); 
country.dataProvider = xml.children(); 
} 
private function statesCompleteHandler(event:Event):void { 
var xml:XML = new XML(_statesService.data); 
state.dataProvider = xml.children(); 
} 
private function changeHandler(event:Event):void { 
var request:URLRequest = new URLRequest("http://www.rightactionscript.com/states/xml/states.php"); 
var parameters:URLVariables = new URLVariables(); 
parameters.country = country.value; 
request.data = parameters; 
_statesService.load(request); 
} 
]]> 
</mx:Script> 
<mx:VBox> 
<mx:ComboBox id="country" change="changeHandler(event)" /> 
<mx:ComboBox id="state" /> 
</mx:VBox> 
</mx:Application> 

4.WebService方法1

<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="initializeHandler(event)"> 
<mx:Script> 
<![CDATA[ 
private function initializeHandler(event:Event):void { 
statesService.getCountries(); 
} 
private function changeHandler(event:Event):void { 
statesService.getStates(country.value); 
} 
]]> 
</mx:Script> 
<mx:WebService id="statesService" 
wsdl="http://www.rightactionscript.com/states/webservice/StatesService.php?wsdl"> 
<mx:operation name="getCountries" /> 
<mx:operation name="getStates" /> 
</mx:WebService> 
<mx:VBox> 
<mx:ComboBox id="country" 
dataProvider="{statesService.getCountries.lastResult}" change="changeHandler(event)" /> 
<mx:ComboBox dataProvider="{statesService.getStates.lastResult}" /> 
</mx:VBox> 
</mx:Application> 

5.WebService方法2

<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="initializeHandler(event)"> 
<mx:Script> 
<![CDATA[ 
private function initializeHandler(event:Event):void { 
statesService.getCountries.send( ); 
} 
private function changeHandler(event:Event):void { 
statesService.getStates.send( ); 
} 
]]> 
</mx:Script> 
<mx:WebService id="statesService" wsdl="http://www.rightactionscript.com/states/webservice/StatesService.php?wsdl"> 
<mx:operation name="getCountries" /> 
<mx:operation name="getStates"> 
<mx:request> 
<country>{country.value}</country> 
</mx:request> 
</mx:operation> 
</mx:WebService> 
<mx:VBox> 
<mx:ComboBox id="country" 
dataProvider="{statesService.getCountries.lastResult}" change="changeHandler(event)" /> 
<mx:ComboBox dataProvider="{statesService.getStates.lastResult}" /> 
</mx:VBox> 
</mx:Application>