Actionscript/Flex: How to maintain the selected item (instead of index) after a Spark list sorts

Question

I change an item in Spark List. The item then moves to a different index in the list since I keep the List's dataProvider sorted. However, the selectedIndex stays where the item used to be. I want the List's selectedIndex to still be on the item that changed. Has anybody solved this problem before or have any tips?

Answer 1

Thanks all, I finally solved this. For posterity, this is what I did:

In my Spark List subclass, I override set dataProvider, and attach a weak-referenced event listener to the dataProvider.

    override public function set dataProvider(theDataProvider:IList):void
    {
        super.dataProvider = theDataProvider;
        dataProvider.addEventListener(CollectionEvent.COLLECTION_CHANGE, onCollectionChange, false, 0, true);
    }

Then, in the event handler, if the item that moved was previously selected, I reselect it. See the CollectionEventKind.MOVE case.

    private function onCollectionChange(theEvent:CollectionEvent):void
    {
        if (theEvent.kind == CollectionEventKind.ADD)
        {
            // Select the added item.
            selectedIndex = theEvent.location;
        }
        else if (theEvent.kind == CollectionEventKind.REMOVE)
        {
            // Select the new item at the location of the removed item or select the new last item if the old last item was removed.
            selectedIndex = Math.min(theEvent.location, dataProvider.length - 1);
        }
        else if (theEvent.kind == CollectionEventKind.MOVE)
        {
            // If the item that moved was selected, keep it selected at its new location.
            if (selectedIndex == theEvent.oldLocation)
            {
                selectedIndex = theEvent.location;
            }
        }   
    }