AnimatedList throws 'itemIndex >= 0 && itemIndex < _itemsCount': is not true. when removing all items when an item is being removed #176362
Description
Steps to reproduce
- Run provided code sample
- Press delete icon on any list item to start long delete animation
- While delete animation is running - press "Clear list" to remove all items from the list
- Observe exception.
Is this a bug or intended behaivour?
What stops me from clearing list?
Expected results
List should be cleared without errors
Actual results
It throws an error.
[ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: 'package:flutter/src/widgets/animated_scroll_view.dart': Failed assertion: line 1398 pos 12: 'itemIndex >= 0 && itemIndex < _itemsCount': is not true.
Code sample
Code sample
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(
debugShowCheckedModeBanner: false,
home: AnimatedListExample(),
);
}
}
class AnimatedListExample extends StatefulWidget {
const AnimatedListExample({super.key});
@override
State<AnimatedListExample> createState() => _AnimatedListExampleState();
}
class _AnimatedListExampleState extends State<AnimatedListExample> {
final GlobalKey<AnimatedListState> _listKey = GlobalKey<AnimatedListState>();
final List<int> _items = List.generate(10, (index) => index);
void _removeItem(int index) {
final removedItem = _items[index];
_listKey.currentState?.removeItem(
index,
(context, animation) => SizeTransition(
sizeFactor: animation,
child: _buildItem(removedItem, animation, isRemoved: true),
),
// 👇 Long delay so you can press "Remove All" while it’s still animating
duration: const Duration(seconds: 10),
);
_items.removeAt(index);
}
void _removeAll() {
_listKey.currentState?.removeAllItems(
(context, animation) {
return SizeTransition(
sizeFactor: animation,
child: Container(
color: Colors.red[100],
child: const ListTile(
title: Text("Removing..."),
),
),
);
},
duration: const Duration(seconds: 2),
);
_items.clear();
}
Widget _buildItem(int item, Animation<double> animation,
{bool isRemoved = false}) {
return SizeTransition(
sizeFactor: animation,
child: Card(
margin: const EdgeInsets.symmetric(vertical: 4, horizontal: 8),
child: ListTile(
title: Text("Item $item"),
trailing: !isRemoved
? IconButton(
icon: const Icon(Icons.delete, color: Colors.red),
onPressed: () {
final index = _items.indexOf(item);
if (index != -1) _removeItem(index);
},
)
: null,
),
),
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("AnimatedList Example"),
actions: [
TextButton(
child: Text("Clear list"),
onPressed: _items.isNotEmpty ? _removeAll : null,
)
],
),
body: AnimatedList(
key: _listKey,
initialItemCount: _items.length,
itemBuilder: (context, index, animation) {
return _buildItem(_items[index], animation);
},
),
);
}
}
Screenshots or Video
Screenshots / Video demonstration
[Upload media here]
Logs
Logs
═══════ Exception caught by gesture ═══════════════════════════════════════════
The following assertion was thrown while handling a gesture:
'package:flutter/src/widgets/animated_scroll_view.dart': Failed assertion: line 1398 pos 12: 'itemIndex >= 0 && itemIndex < _itemsCount': is not true.
Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=02_bug.yml
When the exception was thrown, this was the stack:
#2 _SliverAnimatedMultiBoxAdaptorState.removeItem (package:flutter/src/widgets/animated_scroll_view.dart:1398:12)
animated_scroll_view.dart:1398
#3 _SliverAnimatedMultiBoxAdaptorState.removeAllItems (package:flutter/src/widgets/animated_scroll_view.dart:1443:7)
animated_scroll_view.dart:1443
#4 _AnimatedScrollViewState.removeAllItems (package:flutter/src/widgets/animated_scroll_view.dart:788:48)
animated_scroll_view.dart:788
#5 _AnimatedListExampleState._removeAll (package:bug/main.dart:43:28)
main.dart:43
#6 _InkResponseState.handleTap (package:flutter/src/material/ink_well.dart:1204:21)
ink_well.dart:1204
#7 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:345:24)
recognizer.dart:345
#8 TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:758:11)
tap.dart:758
#9 BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:383:5)
tap.dart:383
#10 BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:314:7)
tap.dart:314
#11 PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:721:9)
recognizer.dart:721
#12 PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:97:12)
pointer_router.dart:97
#13 PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:142:9)
pointer_router.dart:142
#14 _LinkedHashMapMixin.forEach (dart:_compact_hash:764:13)
#15 PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:140:18)
pointer_router.dart:140
#16 PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:130:7)
pointer_router.dart:130
#17 GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:528:19)
binding.dart:528
#18 GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:498:22)
binding.dart:498
#19 RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:473:11)
binding.dart:473
#20 GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:437:7)
binding.dart:437
#21 GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:394:5)
binding.dart:394
#22 GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:341:7)
binding.dart:341
#23 GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:308:9)
binding.dart:308
#24 _invoke1 (dart:ui/hooks.dart:346:13)
hooks.dart:346
#25 PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:467:7)
platform_dispatcher.dart:467
#26 _dispatchPointerDataPacket (dart:ui/hooks.dart:281:31)
hooks.dart:281
(elided 2 frames from class _AssertionError)
Handler: "onTap"
Recognizer: TapGestureRecognizer#7718a
debugOwner: GestureDetector
state: possible
won arena
finalPosition: Offset(1231.0, 32.0)
finalLocalPosition: Offset(46.5, 20.0)
button: 1
sent tap down
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Important issues not at the top of the work listError messages from the Flutter frameworkViewports, list views, slivers, etc.Found to occur in 3.35Found to occur in 3.37flutter/packages/flutter repository. See also f: labels.The issue has been confirmed reproducible and is ready to work onIssue is closed as already fixed in a newer versionOwned by Framework teamTriaged by Framework team