R – Flex Get the XML parent of a selected Tree item

OK. It sounds like your XML looks something like this:

<root>
  <test>
    <child>leaf 1</child>
  </test>
  <test2>
    <child2>leaf 2</child2>
  </test2>
</root>

The significant part of this is that there is simple content within the child and child2 tags. Expanding the tree to show 'leaf 1' or 'leaf 2' causes the error you are receiving, because node.name() will return null. This makes sense, because 'leaf 1' and 'leaf 2' are text nodes and don't have node names.

To correct the problem, you can update the namer function to something along these lines:

public function namer(item:Object):String {
    var node:XML = XML(item);
    var nodeName:QName = node.name();
    if (nodeName) {
        return nodeName.localName;
    } else {
        return String(node);
    }
}

This will use 'leaf 1' and 'leaf 2' as the label for the corresponding nodes in the tree.

You could move the logic that is currently in your change event handler to a separate function, and then call that function directly:

private function changeHandler(event:ListEvent):void
{
    doChangeLogic();
}

private function doChangeLogic():void
{
    //statements
}

public function addSelected(node:XML):void
{
    tree_expandItem(false);                         

    var selectedItem:XML = tree.selectedItem as XML;

    selectedItem.appendChild(node);

    tree_expandItem(true);

    callLater(function():void { tree.selectedItem = node; } );

    doChangeLogic();
}