AnimatedListState class

The AnimatedListState for AnimatedList, a scrolling list container 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 AnimatedList.itemBuilder whenever the item's widget is needed.

When multiple items are inserted with insertAllItems an animation begins running. The animation is passed to AnimatedList.itemBuilder whenever the item's widget is needed.

If using AnimatedList.separated, the animation is also passed to AnimatedList.separatorBuilder whenever the separator'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. If using AnimatedList.separated, the corresponding separator's animation is also passed to the AnimatedList.removedSeparatorBuilder parameter.

An app that needs to insert or remove items in response to an event can refer to the AnimatedList'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);
}

AnimatedList item input handlers can also refer to their AnimatedListState with the static AnimatedList.of method.