Accessing XML with namespaces in AS3 Flex AIR

Accessing xml elements in AS3 with namespaces isn’t straight forward.  I recently had an occasion where I had some incoming xml that defined a namespace in the root element.  When I initially tried to traverse the xml structure to get an xmlList of elements I wasn’t getting anything.  I was puzzled at first but then I saw the xml had defined a namespace and I thought that might be the culprit.  Figuring out how to read the xml with standard E4X syntax root.element.childelement etc. took some time since I never had to work with this before.  Maybe somebody else searching for a solution to this will come accross this and save themselves some time.

Basically I had some xml coming in from a request that looked like this:

<xml>
<serviceResponse xmlns=”http://cafesilencio.net/doc/blahblahblah/”>
<someElement>
<childElement>twinkies are yummy</childElement>
<childElement>donuts are delicious</childElement>
</someElement>
<serviceResponse>
</xml>

The following code WON’T work:

var childList:XMLList = serviceResponse.someElement.childElement;

The xml is sort of locked or maybe protected would be a better word. So to access it you can first declare a namespace. Then you call a directive to use the namespace before traversing the xml. So one way to do it would look like this:

package com.mypackage.util
{
     public class MyClass
     {
           //declare the namespace,
          //notice it's the same as the xmlns attribute in the root of the xml
          private namespace cafesilencioNameSpace = "http://cafesilencio.net/doc/blahblahblah/";

...

     public function doSomethingWithTheXML(xmlDoc:XML):void
     {
          //this is important, we're indicating we want to use a specific namespace
          use namespace cafesilencioNameSpace;
          var childList:XMLList = xmlDoc.someElement.childElement;
          //do something with the childList
     }
}

This isn’t the only way to do it but it worked for me and now I can get back to coding.