flutter_tags
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Published
20 hours ago •
Dn-a
Dn-a
type 'Null' is not a subtype of type 'DataList' in type cast
I'm trying to integrate this library into my project and I want to let users choose items from a list or add their own items to it. Here is what I have so far:
final GlobalKey<TagsState> _tagStateKey = GlobalKey<TagsState>();
List<String> _existingTopics = ['religion', 'politics', 'literature'];
List<String> _topics = [];
...
Tags(
key: _tagStateKey,
textField: TagsTextField(
constraintSuggestion: true,
suggestions: _existingTopics,
//width: double.infinity, padding: EdgeInsets.symmetric(horizontal: 10),
onSubmitted: (String str) {
// Add item to the data source.
setState(() {
// required
_topics.add(str);
});
},
),
itemCount: _topics.length, // required
itemBuilder: (int index) {
final topic = _topics[index];
return ItemTags(
// Each ItemTags must contain a Key. Keys allow Flutter to
// uniquely identify widgets.
key: Key(index.toString()),
index: index, // required
title: topic,
combine: ItemTagsCombine.withTextBefore,
image: null,
icon: null,
removeButton: ItemTagsRemoveButton(
onRemoved: () {
// Remove the item from the data source.
setState(() {
_topics.removeAt(index);
});
return true;
},
),
);
},
)
But when I start typing one of the _existingTopics and then type the submit button on the iOS keyboard, I see this:
And I get the following exception:
[+165250 ms] flutter: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
[ +2 ms] flutter: The following _CastError was thrown building ItemTags-[<'0'>](dirty, dependencies:
[ ] flutter: [DataListInherited], state: _ItemTagsState#81225):
[ ] flutter: type 'Null' is not a subtype of type 'DataList' in type cast
[ ] flutter:
[ ] flutter: The relevant error-causing widget was:
[ +8 ms] flutter: ItemTags-[<'0'>] file:///Users/sarbogast/dev/blindly/blindly/lib/screens/topics_screen.dart:108:28
[ ] flutter:
[ ] flutter: When the exception was thrown, this was the stack:
[ ] flutter: #0 List.length= (dart:core-patch/growable_array.dart:222:12)
[ ] flutter: #1 _ItemTagsState._setDataList (package:flutter_tags/src/item_tags.dart:153:33)
[ ] flutter: #2 _ItemTagsState.build (package:flutter_tags/src/item_tags.dart:214:5)
[ ] flutter: #3 StatefulElement.build (package:flutter/src/widgets/framework.dart:4612:27)
[ ] flutter: #4 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4495:15)
[ ] flutter: #5 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #6 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #7 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4474:5)
[ ] flutter: #8 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4658:11)
[ ] flutter: #9 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4469:5)
[ ] flutter: #10 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3541:14)
[ ] flutter: #11 Element.updateChild (package:flutter/src/widgets/framework.dart:3306:18)
[ ] flutter: #12 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5561:32)
[ ] flutter: #13 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6105:17)
[ ] flutter: #14 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #15 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ +16 ms] flutter: #16 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #17 ProxyElement.update (package:flutter/src/widgets/framework.dart:4843:5)
[ ] flutter: #18 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #19 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #20 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #21 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #22 StatefulElement.update (package:flutter/src/widgets/framework.dart:4699:5)
[ ] flutter: #23 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #24 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #25 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #26 ProxyElement.update (package:flutter/src/widgets/framework.dart:4843:5)
[ ] flutter: #27 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #28 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5503:32)
[ ] flutter: #29 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6105:17)
[ ] flutter: #30 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #31 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5981:14)
[ ] flutter: #32 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #33 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #34 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #35 ProxyElement.update (package:flutter/src/widgets/framework.dart:4843:5)
[ ] flutter: #36 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #37 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5981:14)
[ ] flutter: #38 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #39 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #40 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #41 StatelessElement.update (package:flutter/src/widgets/framework.dart:4576:5)
[ ] flutter: #42 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #43 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #44 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #45 StatelessElement.update (package:flutter/src/widgets/framework.dart:4576:5)
[ ] flutter: #46 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #47 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #48 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #49 ProxyElement.update (package:flutter/src/widgets/framework.dart:4843:5)
[ ] flutter: #50 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #51 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #52 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #53 ProxyElement.update (package:flutter/src/widgets/framework.dart:4843:5)
[ ] flutter: #54 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #55 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5503:32)
[ ] flutter: #56 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6105:17)
[ ] flutter: #57 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #58 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #59 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #60 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #61 StatefulElement.update (package:flutter/src/widgets/framework.dart:4699:5)
[ ] flutter: #62 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #63 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #64 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #65 ProxyElement.update (package:flutter/src/widgets/framework.dart:4843:5)
[ +17 ms] flutter: #66 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #67 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #68 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #69 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #70 StatefulElement.update (package:flutter/src/widgets/framework.dart:4699:5)
[ ] flutter: #71 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #72 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5981:14)
[ ] flutter: #73 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #74 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #75 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #76 StatelessElement.update (package:flutter/src/widgets/framework.dart:4576:5)
[ ] flutter: #77 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #78 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5981:14)
[ ] flutter: #79 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #80 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #81 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #82 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #83 StatefulElement.update (package:flutter/src/widgets/framework.dart:4699:5)
[ ] flutter: #84 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #85 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #86 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #87 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #88 StatefulElement.update (package:flutter/src/widgets/framework.dart:4699:5)
[ ] flutter: #89 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #90 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #91 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #92 ProxyElement.update (package:flutter/src/widgets/framework.dart:4843:5)
[ ] flutter: #93 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #94 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #95 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #96 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #97 StatefulElement.update (package:flutter/src/widgets/framework.dart:4699:5)
[ ] flutter: #98 Element.updateChild (package:flutter/src/widgets/framework.dart:3293:15)
[ ] flutter: #99 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4520:16)
[ ] flutter: #100 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4667:11)
[ ] flutter: #101 Element.rebuild (package:flutter/src/widgets/framework.dart:4189:5)
[ ] flutter: #102 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2694:33)
[ ] flutter: #103 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:873:21)
[ ] flutter: #104 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:319:5)
[ ] flutter: #105 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144:15)
[ ] flutter: #106 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1082:9)
[ ] flutter: #107 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:998:5)
[ ] flutter: #111 _invoke (dart:ui/hooks.dart:161:10)
[ ] flutter: #112 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:253:5)
[ ] flutter: #113 _drawFrame (dart:ui/hooks.dart:120:31)
[ ] flutter: (elided 3 frames from dart:async)
And the component crashes. Did I forget something?
Note that I am using Flutter 2.0.5 with null safety, along with version 1.0.0-nullsafety.1 of the flutter_tags library
type 'Null' is not a subtype of type 'DataList' in type cast
item_tags.dart 151 line // set List length if (_dataListInherited!.list!.length < _dataListInherited!.itemCount!) _dataListInherited!.list!.length = _dataListInherited!.itemCount!;
I am also getting the same error. It worked just fine before migrating to null safety. The error is thrown for each ItemTags element built. If the list is empty no error is thrown.
remove
if (_dataListInherited!.list!.length < _dataListInherited!.itemCount!) _dataListInherited!.list!.length = _dataListInherited!.itemCount!;
and rerun your app. it worked for me.
if (_dataListInherited!.list!.length < _dataListInherited!.itemCount!) _dataListInherited!.list!.length = _dataListInherited!.itemCount!; commenting this out worked , can we update this
@sarbogast @Dn-a Same, it showstopper, could you please check? #84 Merge maybe or give me an answer, please Update Flutter has already a native widget Chip or ActionChip
commented this don't worked for me.
if (_dataListInherited!.list!.length < _dataListInherited!.itemCount!)
_dataListInherited!.list!.length = _dataListInherited!.itemCount!;
I changed final List<DataList> _list = []; to final List<DataList?> _list = []; and correct the errors that follow from here
It's worked
