Check out this answer on Stack Overflow: Animating Child Elements in Flex 4.
Flex 3 Lists had the itemChangeEffect/dataChangeEffect baked into them, and they had to do a LOT of custom configuration inside of the List component to make that possible. Because Spark is a lot newer and a lot better architected, they have not included any effect processing in the components, so you can t do things like itemChangeEffects.
What you CAN do, though, is create effects in your layouts. If you wanted to create an AnimatedVerticalLayout
, all you need to do is extend their VerticalLayout and override updateDisplayList, and then use TweenMax to animate your items in and out of their state. It s not very easy :/ but it s the only thing you can really do right now. Once someone automates this process though, it ll be a snap.
Good luck!
Check out this example: Animated TimeMachine Layout by Gilles Guillemin. He has some good stuff.