Recursively iterating over all child controls

Question

Hi All,
I'm trying to recursively iterate over all child controls in my Flex 4 application, and I've been doing something like this to get the immediate children of a particular container:
public static function getElements(parent:Object):Vector.<IVisualElement>{
     var result:Vector.<IVisualElement> = new Vector.<IVisualElement>();
     for(var i:int = 0; i < parent.numElements; i++){
          result.push(parent.getElementAt(i));
     return result;
I can then call that function recursively.  It works--kinda.  The way it doesn't work is that if I call this object on the application object itself, it will only give me back elements that are visible in the current state.  As I move from one state to another, different elements are returned by my getElements method.
So, is there are way I can find all child elements, whether or not they are visible in the current state?
  -Josh

Answer 1

Hi Josh,
So, I've come up with some quick code for you. However, I must add my disclaimers first:
The code is incomplete in that it excludes children of children that don't use states, but includes children of children that are associated with states of the parent. I'm also definitely not an expert in how our states system works.
I'm not sure what your use case for all of this is, but my best guess is that it would be better to find a different way to solve your problem than to go the route of introspecting states. It's a long and dirty road =).
Other than that, I've attached the code for you. The meat of this is:
     *  Finds all elements in all states that use the states of the specified parent.
    public static function getAllElements(parent:UIComponent):Vector.<IVisualElement>
        var container:IVisualElementContainer = parent as IVisualElementContainer;
        if (!container)
            return new Vector.<IVisualElement>();
        var result:Vector.<IVisualElement> = getCurrentElements(container);
        var states:Array = parent.states;
        for each (var state:State in parent.states)
            for each (var addItems:AddItems in state.overrides)
                var elt:IVisualElement = addItems.items as IVisualElement;
                if (elt && !containsElement(result, elt))
                    result.push(elt);
        return result;
This method takes the parent container (in my case, the application) and returns a vector of children elements that associate themselves with the states of this parent container. First, it grabs all the elements already created from the parent container. Next, it iterates over each state and then each AddItems of each state. The AddItems object contains the information and pointers to the specific element that will be "added" when the current state changes to that state. By calling addItems.items, we force the creation of the specific element which is returned to us. Now, we can use a simple containsElement() method to check for duplicates and build a list of elements that would be added to each of the states.
Again, the code is finding all of the children of the provided parent in all of its parent's states; however, it also finds children of children that may be using the parent's states as well. But if the children of children are not using the parent's states then it will not be found (easily fixable if you recurse). In addition, knowing which elements belong to which container just from introspecting the State object is pretty complicated and involves understanding how addItems.apply() works.
Anyway, I hope this helps you. I would be interested in hearing your use case since this code is pretty complicated. I'd like to see if I could help by finding a different approach for your problem.
-Kevin