Flex update XML - actionscript-3

Question

im new to flex development and in need of assistance.
I have a xml file that contains data that i would like to update if the user changes anything, the file is saved on his local program files where the application is.
Here is my code that reads the XML file:
<fx:Declarations>
<s:HTTPService id="systemData" url="data/system.xml" method="POST"/>
</fx:Declarations>
<fx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.rpc.events.ResultEvent;
[Bindable]
private var systemInfo:Object = new Object();
private var interval:uint;
[Bindable]
private var xmlData:ArrayCollection = new ArrayCollection();
private function viewMain(event:Event):void
{
mainWindow.visible = true;
systemWindow.visible = false;
}
private function viewSystem(event:Event):void
{
mainWindow.visible = false;
systemWindow.visible = true;
}
public function init():void
{
systemData.addEventListener(ResultEvent.RESULT, getXML);
systemData.send();
interval = setInterval(reloadXML, 1800000);
}
private function getXML(e:ResultEvent):void
{
systemInfo = systemData.lastResult.system;
systemIP.text = systemInfo.systemip;
systemPort.text = systemInfo.systemport;
systemUsername.text = systemInfo.systemusername;
systemPassword.text = systemInfo.systempassword;
}
private function reloadXML():void
{
systemData.send();
}
]]>
</fx:Script>
<s:BorderContainer id="mainWindow" width="100%" height="100%" visible="false">
<s:Button x="434" y="102" label="System Settings" click="viewSystem(event)"/>
<s:Button x="468" y="147" label="Button" />
</s:BorderContainer>
<s:BorderContainer id="systemWindow" width="100%" height="100%" visible="true">
<s:Panel width="800" height="600" horizontalCenter="0" title="System Settings"
verticalCenter="0">
<s:Label x="33" y="41" text="Server IP:"/>
<s:Label x="33" y="66" text="Port:"/>
<s:Label x="33" y="90" text="Username:"/>
<s:Label x="33" y="115" text="Password:"/>
<s:TextInput x="182" y="31" width="250" id="systemIP"/>
<s:TextInput x="182" y="56" width="250" id="systemPort"/>
<s:TextInput x="182" y="80" width="250" id="systemUsername"/>
<s:TextInput x="182" y="105" width="250" id="systemPassword"/>
<s:Button x="345" y="135" label="Save to XML" />
<s:Button x="718" y="-26" label="Main" click="viewMain(event)"/>
</s:Panel>
</s:BorderContainer>
The XML File:
<?xml version="1.0" encoding="utf-8" standalone="no"?>
<system>
<systemip>127.0.0.0</systemip>
<systemport>80</systemport>
<systemusername>rootu</systemusername>
<systempassword>passu</systempassword>
</system>
Thanks in advance

Answer 1

To write the updated content back in your xml file, you need to write the file back. I assume your application is an Adobe AIR application. You can make use of "File" class to read and write the content.
Link: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/filesystem/File.html