Flex Change List Item Selected While Mouse Down - list

Question

I am trying to create a List which behaves like, for example, the Finder Menu on my Mac. In other words if I click on a List Item, keep my mouse down and move up and down the List I want the Selected Item to change.
In my Flex application if I click on my List and then, with the mouse still down, move up and down the List the Selected Item remains the same.
Any advice would be gratefully received.
Thanks

Answer 1

In StackOverflow tradition I am posting a solution to my own problem after working at it more:
I had an ItemRenderer on my List. In the ItemRenderer I declared a variable to hold a reference to the owning List.
private var _parentList:List;
In the 'set data' function I set this variable to the owner List.
override public function set data(value:Object):void {
super.data = value;
// Check to see if the data property is null.
if (value == null)
return;
// If the data property is not null.
// Get a reference to the parent list.
_parentList = this.owner as List;
...
I then added an EventListener to listen for MouseDown events.
// Attach an eventListener to the ItemRenderer.
this.addEventListener(MouseEvent.MOUSE_OVER, onMouseOver);
...
My onMouseOver handler looks like this.
private function onMouseOver(event:MouseEvent):void {
//trace(data.LocationName);
if (event.buttonDown == true) {
_parentList.selectedIndex = itemIndex;
}
}
So with this in place I can mouse-down on my List and keeping the mouse button depressed move up and down the List with the List Item beneath the cursor always being selected. The final piece to this is to ensure that the List responds to the selectedIndex being set by the ItemRenderer. When the user changes the selectedIndex property by interacting with the control, the control dispatches the change and changing events. When you change the value of the selectedIndex property programmatically, it dispatches the valueCommit event. To ensure I responded to my programmatic changing of the selected list item I added a handler to the valueCommit event.
<s:List
id="locationsList"
dataProvider="{presenter.locations}"
itemRenderer="itemrenderers.locationListItemRenderer"
useVirtualLayout="false"
width="1869.698" height="1869.698"
y="65.151" x="65.151"
borderVisible="true"
borderColor="{presenter.backgroundColour}"
contentBackgroundAlpha="0"
contentBackgroundColor="0xff336c"
labelField="label"
change="presenter.onLocationListChange(event)"
valueCommit="presenter.onLocationListValueCommit(event)">
<s:layout>
<s:BasicLayout />
</s:layout>
</s:List>
So far it seems to work fine. Hope it helps.