"Looking up a deactivated widget's ancestor is unsafe." with StatefullWidget

Question

I can't find any answers for my problem. In the code below, everything was perfect if I use a "GestureDetector" with a "Image" instead the Dismissible with the PhotoView. When I run it, it throws the "ancestor is unsafe" error.

My code id for show the pages of a comic. The code line "comic.paginaActual(comic.readProgress.page)" returns a NetworkImage with the comic page. When the user "dismiss" the page (using the dismissible widget), the app loads the next page (at least is the expected result).

As I said, i've tried with a Gesture detector (with horizontal gesture for the swipe) and just "Image" instead Photoview and it worked perfect, but when I use the Dismissible, the app crashes.

This is the code:

// ignore: use_key_in_widget_constructors
class PaginaFull extends StatefulWidget {
  @override
  State<PaginaFull> createState() => _PaginaFullState();
}

class _PaginaFullState extends State<PaginaFull> {
  late PhotoViewScaleStateController scaleController;
  DismissDirection dismissDirection = DismissDirection.horizontal;

  @override
  void didChangeDependencies() {
    _enterFullscreen();
    scaleController = PhotoViewScaleStateController();
    super.didChangeDependencies();
  }

  @override
  void initState() {
    super.initState();
  }

  @override
  void dispose() {
    super.dispose();
    _exitFullscreen();
    scaleController.dispose();
  }

  _enterFullscreen() async {
    await FullScreen.enterFullScreen(FullScreenMode.EMERSIVE);
  }

  _exitFullscreen() async {
    await FullScreen.exitFullScreen();
  }

  void paginaSiguiente({required Comic comic}) {
    if (comic.readProgress.page < (comic.media.pagesCount)) {
      setState(() {
        comic.readProgress.page += 1;
      });
    }
  }

  void paginaAnterior({required Comic comic}) {
    if (comic.readProgress.page > 1) {
      setState(() {
        comic.readProgress.page -= 1;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final Comic comic = ModalRoute.of(context)!.settings.arguments as Comic;

    return Scaffold(
      appBar: null,
      body: Builder(builder: (context) {
        return AnimatedSwitcher(
          duration: const Duration(milliseconds: 300),
          child: Dismissible(
            behavior: HitTestBehavior.translucent,
            key: Key(comic.readProgress.page.toString()),
            direction: dismissDirection,
            onDismissed: (DismissDirection direction) {
              if (direction == DismissDirection.startToEnd) {
                paginaAnterior(comic: comic);
              } else {
                paginaSiguiente(comic: comic);
              }
            },
            resizeDuration: null,
            child: PhotoView(
              scaleStateController: scaleController,
              filterQuality: FilterQuality.high,
              initialScale: PhotoViewComputedScale.contained,
              minScale: PhotoViewComputedScale.contained,
              gaplessPlayback: true,
              enableRotation: false,
              imageProvider: comic.paginaActual(comic.readProgress.page),
            ),
          ),
        );
      }),
    );
  }
}

Perhaps changing the experience with others widgets.... but i'm new in flutter and i don't now know what else i can use.

Thanks in advance for your help!... from CHILE!

Answer 1

Solved!!!

The problem is coming from photo_view package.

In pubspec.yaml remove photo_view from dependecies

dependencies: photo_view: ^0.13.0 Add:

dependency_overrides: photo_view: git: url: https://github.com/bluefireteam/photo_view ref: master

This avoid the problem!!!