Could not find the correct Provider<> with Hero animation Flutter

Issue

I’m pushing a new Route in my Gallery file to the Details file with a Hero animation. Everything is fine but when I’m calling the pop() inside the details file to go back to Gallery, I have a Provider error :

flutter: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
flutter: The following ProviderNotFoundException was thrown building GalleryThumbnail(dirty, state:
flutter: _GalleryThumbnailState#9dc96):
flutter: Error: Could not find the correct Provider<GalleryViewModel> above this GalleryThumbnail Widget

Here is my gallery file :

@override
  Widget build(BuildContext context) {
    return MultiProvider(
        providers: [
          ChangeNotifierProvider.value(value: galleryViewModel),
          ChangeNotifierProvider.value(value: galleryProvider)
        ],
        child: Scaffold(
            resizeToAvoidBottomInset: false,
            body: Stack(
              children: [
                Consumer<GalleryViewModel>(
                    builder: (context, model, child) =>
                        galleryViewModel.assetsList.length != 0 ? gallery() : emptyGallery()),

...

}


Widget gallery() {
    return Container(
      padding: EdgeInsets.only(left: 5, right: 5, top: 5),
      child: CupertinoScrollbar(
        child: GridView.builder(
          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: 3,
              crossAxisSpacing: 2,
              mainAxisSpacing: 2,
              childAspectRatio: 0.85,
            ),
          itemCount: galleryViewModel.assetsList.length,
          padding: EdgeInsets.only(bottom: Constants.navBarSize),
          physics: BouncingScrollPhysics(),
          shrinkWrap: true,
          itemBuilder: (context, index) {
            if(index >= galleryViewModel.assetsList.length-30) {
              galleryViewModel.onLoadMore(index);
            }
            return _galleryItem(index);
          },

        ),
      ),
    );
  }


Widget _galleryItem(int index) {
    return Stack(
      children: [
        Consumer<GalleryProvider>(
          builder: (context, model, child) {
            return Container(
              padding:
                  multipleSelection ? EdgeInsets.all(2) : EdgeInsets.all(0),
              decoration: multipleSelection ? BoxDecoration(
                      borderRadius: BorderRadius.circular(20),
                      border: Border.all(color: Colors.transparent , width: 2)) : BoxDecoration(),
              child: child,
            );
          },
            Hero(
            createRectTween: (Rect? begin, Rect? end) {
              RectTween _rectTween =
              RectTween(begin: begin, end: end);
              return _rectTween;
            },
            tag: galleryViewModel.assetsList[index].id,
            child:
          child: GalleryThumbnail(
            asset: galleryViewModel.assetsList[index],
           
            onTap: (data) {
              Navigator.push(context, MaterialPageRoute(builder: (context) {
                  return MediaEditorPage(
                      asset: galleryViewModel.assetsList[index],
                      bytes: data);
                }));
            },
          ),


...

}

When I’m pushing without the hero or another route there is no error and I don’t why the provider could not be find above the Hero, I’m not notifying any provider while navigator transitions.

Why I’m getting a provider error here and how to fix this ?

Thanks for any help

Solution

When using Hero widget, it seems there is a Context issue.

This means that when the animation is performing, and in the destination you are calling a Provider.of<Model>(context), it will not find the correct Provider.

You simply need to do as you would do with a Navigator which gives in your example :

Hero(
  createRectTween: (Rect? begin, Rect? end) {
    RectTween _rectTween =
    RectTween(begin: begin, end: end);
    return _rectTween;
  },
  tag: galleryViewModel.assetsList[index].id,
  child: ChangeNotifierProvider.value(
    value: galleryViewModel,
    child: GalleryThumbnail(
      asset: galleryViewModel.assetsList[index],
      size: size,
      onLongPress: () {
        if (!multipleSelection) {
          multipleSelection = true;
          galleryViewModel.selectedAssets.add(galleryViewModel.assetsList[index]);
          galleryProvider.notify();
        }
      },
      onTap: (data) {
        Navigator.push(context, MaterialPageRoute(builder: (context) {
                  return MediaEditorPage(
                      asset: galleryViewModel.assetsList[index],
                      bytes: data);
                }));
      },
    ),
  ),
)

I have added : ChangeNotifierProvider.value(value: galleryViewModel) wrapping the GalleryThumbnail.

Answered By – Tom3652

Answer Checked By – Candace Johnson (FlutterFixes Volunteer)

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