AnimatedGridState class

The State for an AnimatedGrid 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 AnimatedGrid.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 AnimatedGrid's state with a global key:

// (e.g. in a stateful widget)
GlobalKey<AnimatedGridState> gridKey = GlobalKey<AnimatedGridState>();

// ...

@override
Widget build(BuildContext context) {
  return AnimatedGrid(
    key: gridKey,
    itemBuilder: (BuildContext context, int index, Animation<double> animation) {
      return const Placeholder();
    },
    gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(maxCrossAxisExtent: 100.0),
  );
}

// ...

void _updateGrid() {
  // adds "123" to the AnimatedGrid
  gridKey.currentState!.insertItem(123);
}

AnimatedGrid item input handlers can also refer to their AnimatedGridState with the static AnimatedGrid.of method.