XMLNodes being appended to an XMLNode are "undefined"? Actionscript 2.0 is being unkind
- by DigitalMercenary
If anyone can offer an explanation for this one, I'd LOVE to see it! I was required to append a legacy application to display 20 random questions from an XML data source, as opposed to the total of 70 questions that are part of the original XML. No big deal, right? WRONG! I got it to work just fine in the end, but it's a total HACK! For some reason, some of the nodes that I am appending to a dynamically generated XML document are being returned as "undefined". I kept getting between 16 and 20 questions to render until I modified my iteration from a 'for' loop to a 'do while' loop with the appropriate number of XMLNodes as the condition of the 'do while' loop. Can anyone offer an explanation? Below is the code, with some notes for the reader :
function editXML(xml:XML):XML
{
var node:XMLNode = xml.firstChild;
var newNode:XMLNode = new XMLNode();
var nodeArray:Array = new Array();
var usedNodes:Array = new Array();
var totalNodes:Number = node.lastChild.childNodes.length - 1;
var nextNode:Number;
var returnNode:XMLNode = new XMLNode();
var tempNode:XMLNode;
var buildNode:XMLNode;
var addNode:Boolean = true;
var tempXML:XML = new XML();
var pagesNode:XMLNode = tempXML.createElement("pages");
tempXML.appendChild(pagesNode);
tempXML.appendChild(node.childNodes[0]);
tempXML.appendChild(node.childNodes[1]);
tempXML.appendChild(node.childNodes[2]);
var questionsNode:XMLNode = tempXML.createElement("pages");
tempXML.firstChild.appendChild(questionsNode);
do
{
nextNode = Math.floor(Math.random()*totalNodes);
**//random number to represent random node**
//trace(nextNode + " nextNode");
**//check usedNodes Array to look for node.childNodes[nextNode]. If it already exists, skip and reloop.**
trace(node.childNodes[1].childNodes[nextNode] + " : pre building Node " + totalNodes);
if(usedNodes.length == 0)
{
buildNode = new XMLNode();
buildNode.nodeName = node.childNodes[1].childNodes[nextNode].nodeName;
buildNode.nodeValue = node.childNodes[1].childNodes[nextNode].nodeValue;
tempXML.firstChild.lastChild.appendChild(node.childNodes[1].childNodes[nextNode])
usedNodes.push(node.childNodes[1].childNodes[nextNode]);
nodeArray.push(node.childNodes[1].childNodes[nextNode]);
trace("adding first node : " + nodeArray.length);
addNode = false;
}
else
{
for(var j:Number = 0; j < usedNodes.length; j++)
{
if(usedNodes[j] == node.childNodes[1].childNodes[nextNode])
{
addNode = false;
trace("skipping node : " + nodeArray.length);
}
}
}
**//if node not in usedNodes, add node to XML**
if(addNode)
{
trace(node.childNodes[1].childNodes[nextNode] + " : building Node"); **//This trace statement produced a valid node**
tempXML.firstChild.lastChild.appendChild(node.childNodes[1].childNodes[nextNode]);
**//Before modifying the code from adding nodes to the xml from an Array called 'nodeArray' in a for loop to adding nodes directly to the xml in a do while loop with the length of the xml node used to retrieve data for the questions as the condition, I was not always getting 20 questions. Some of the nodes were being rendered as 'undefined' and not appended to the xml, even though they were traced and proven valid before the attemp to append them to the xml was made**
usedNodes.push(node.childNodes[1].childNodes[nextNode]);
}
addNode = true;
}
while(tempXML.firstChild.lastChild.childNodes.length <= 19);
trace(tempXML.firstChild.lastChild.childNodes.length + " final nodes Length");
courseXML = tempXML;
//removes the old question list of 70 and replaces it with the new question list of 20. Question list is the last node.
return tempXML;
}
If I had my choice, I would have rebuilt the whole application in Flex with AS3. I didn't have that choice. If anyone can explain this mystery, PLEASE DO! Thank you in advance!
