Flutter Retrigger Staggered Animation on ListView

Question

I am using flutter_staggered_animations in my app for my listView. It is working quite nice when starting the app.

Problem:

I want the animation to be triggered if I change the child-widget of the listView or even just the itemCount. So what I need is a rebuild of the staggeredList.

But how can I do that? I tried simply changing the child or itemCount with setState. But that is triggering an animation...

Couldn't find anything on this. Let me know if you need more info!

I use pretty much the exact code from the example:

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: AnimationLimiter(
      child: ListView.builder(
        itemCount: 100,
        itemBuilder: (BuildContext context, int index) {
          return AnimationConfiguration.staggeredList(
            position: index,
            duration: const Duration(milliseconds: 375),
            child: SlideAnimation(
              verticalOffset: 50.0,
              child: FadeInAnimation(
                child: YourListChild(),
              ),
            ),
          );
        },
      ),
    ),
  );
}

Answer 1

You can provide a new key on AnimationLimiter, and it will recreate the AnimationLimiter,

AnimationLimiter(
  key: ValueKey("$itemCount"),
  child: ListView.builder(

class STA extends StatefulWidget {
  const STA({super.key});

  @override
  State<STA> createState() => _STAState();
}

class _STAState extends State<STA> {
  int itemCount = 5;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          itemCount++;
          setState(() {});
        },
      ),
      body: AnimationLimiter(
        key: ValueKey("$itemCount"),
        child: ListView.builder(
          itemCount: itemCount,
          itemBuilder: (BuildContext context, int index) {
            return AnimationConfiguration.staggeredList(
              position: index,
              duration: const Duration(milliseconds: 375),
              child: SlideAnimation(
                verticalOffset: 50.0,
                child: FadeInAnimation(
                  child: Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: Container(
                      height: 50,
                      color: index.isEven ? Colors.amber : Colors.purple,
                    ),
                  ),
                ),
              ),
            );
          },
        ),
      ),
    );
  }
}