SliverAnimatedListState class

The state for a SliverAnimatedList that animates items when they are inserted or removed.

When an item is inserted with insertItem an animation begins running. The animation is passed to SliverAnimatedList.itemBuilder whenever the item's widget is needed.

When an item is removed with removeItem its animation is reversed. The removed item's animation is passed to the removeItem builder parameter.

An app that needs to insert or remove items in response to an event can refer to the SliverAnimatedList's state with a global key:

// (e.g. in a stateful widget)
GlobalKey<AnimatedListState> listKey = GlobalKey<AnimatedListState>();

// ...

@override
Widget build(BuildContext context) {
  return AnimatedList(
    key: listKey,
    itemBuilder: (BuildContext context, int index, Animation<double> animation) {
      return const Placeholder();
    },
  );
}

// ...

void _updateList() {
  // adds "123" to the AnimatedList
  listKey.currentState!.insertItem(123);
}

SliverAnimatedList item input handlers can also refer to their SliverAnimatedListState with the static SliverAnimatedList.of method.