Flutter_html: Getting '<Unexpected Null Value>' using with Flutter Web
Just by using this simple script:
import 'package:flutter/material.dart';
import 'package:flutter_html/flutter_html.dart';
class TestScreen extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Html(
data: '<p>Test</p>',
),
);
}
}
And trying it on web I get the following error:
══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
The following NoSuchMethodError was thrown during performLayout():
'<Unexpected Null Value>'
method not found
Receiver: null
Arguments: []
The relevant error-causing widget was:
Text
file:///Users/jan/.pub-cache/hosted/pub.dartlang.org/flutter_html-1.0.0/lib/html_parser.dart:719:19
When the exception was thrown, this was the stack:
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 216:49 throw_
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 58:3 throwNullValueError
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 488:39 _notNull
packages/flutter/src/widgets/widget_span.dart 108:37 build
packages/flutter/src/painting/text_span.dart 211:14 build
packages/flutter/src/painting/text_span.dart 211:14 build
packages/flutter/src/painting/text_painter.dart 558:13 layout
packages/flutter/src/rendering/paragraph.dart 490:18 [_layoutText]
packages/flutter/src/rendering/paragraph.dart 513:5 [_layoutTextWithConstraints]
packages/flutter/src/rendering/paragraph.dart 581:5 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 266:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/shifted_box.dart 394:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/shifted_box.dart 207:11 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/paragraph.dart 530:12 [_layoutChildren]
packages/flutter/src/rendering/paragraph.dart 580:5 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 266:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/shifted_box.dart 394:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/paragraph.dart 530:12 [_layoutChildren]
packages/flutter/src/rendering/paragraph.dart 580:5 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 266:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 266:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/custom_layout.dart 171:10 layoutChild
packages/flutter/src/material/scaffold.dart 480:7 performLayout
packages/flutter/src/rendering/custom_layout.dart 240:7 [_callPerformLayout]
packages/flutter/src/rendering/custom_layout.dart 399:14 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/proxy_box.dart 1265:11 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/proxy_box.dart 3242:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/widgets/overlay.dart 700:14 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/proxy_box.dart 111:13 performLayout
packages/flutter/src/rendering/object.dart 1767:7 layout
packages/flutter/src/rendering/view.dart 167:48 performLayout
packages/flutter/src/rendering/object.dart 1630:7 [_layoutWithoutResize]
packages/flutter/src/rendering/object.dart 887:17 flushLayout
packages/flutter/src/rendering/binding.dart 402:19 drawFrame
packages/flutter/src/widgets/binding.dart 865:13 drawFrame
packages/flutter/src/rendering/binding.dart 284:5 [_handlePersistentFrameCallback]
packages/flutter/src/scheduler/binding.dart 1074:15 [_invokeFrameCallback]
packages/flutter/src/scheduler/binding.dart 1013:9 handleDrawFrame
packages/flutter/src/scheduler/binding.dart 822:7 <fn>
dart-sdk/lib/_internal/js_dev_runtime/private/isolate_helper.dart 50:19 internalCallback
The following RenderObject was being processed when the exception was fired: RenderParagraph#ab787 relayoutBoundary=up12 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE:
creator: RichText ← Text ← SizedBox ← StyledText ← Align ← DecoratedBox ← Padding ← Container ←
ContainerSpan ← RichText ← Text ← SizedBox ← ⋯
parentData: <none> (can use size)
constraints: BoxConstraints(w=1645.0, 0.0<=h<=Infinity)
size: MISSING
textAlign: start
textDirection: ltr
softWrap: wrapping at box width
overflow: clip
locale: en_US
maxLines: unlimited
This RenderObject had the following descendants (showing up to depth 5):
text: TextSpan
TextSpan
WidgetSpan#ec776
════════════════════════════════════════════════════════════════════════════════════════════════════
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: Assertion failed: file:///Users/jan/flutter/packages/flutter/lib/src/rendering/box.dart:1694:12
Another exception was thrown: NoSuchMethodError: '<Unexpected Null Value>'
This is my flutter doctor
[✓] Flutter (Channel beta, 1.18.0-11.1.pre, on Mac OS X 10.15.4 19E287, locale en-US)
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
[✓] Xcode - develop for iOS and macOS (Xcode 11.5)
[✓] Chrome - develop for the web
[✓] Android Studio (version 3.6)
[!] VS Code (version 1.45.1)
✗ Flutter extension not installed; install from
https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter
[✓] Connected device (3 available)
bug
jlubeck
👍10
👀4
All 11 comments
Did you solve this somehow? Stuck at the same after upgrading to 1.0.0.
datayeah
on 24 May 2020
Any update on this?
JaviBonilla
on 31 May 2020
I am getting the same issue in 1.0.0 Flutter Web
Swapnilgshah
on 5 Jun 2020
I can also confirm this issue
RyanSusana
on 5 Jun 2020
I'll take a look at this sometime this week as it looks critical. From what I understand, we don't officially Web, but if this is the only thing holding us from fully supporting Flutter Web, I don't mind supporting it
ryan-berger
on 7 Jun 2020
👍6
I can confirm that 0.11 does work on the web
RyanSusana
on 7 Jun 2020
After upgrading to 1.0.0 because to use tags web does not work anymore
strifel
on 8 Jun 2020
I am getting the same issue in 1.0.0 Flutter Web
But works with flutter_html: ^0.9.6
Swapnilgshah
on 9 Jun 2020
I get a similar error but with IntrinsicHeight after I upgraded to 1.0.0, with Flutter SDK 1.17.3:
════════ Exception caught by rendering library ═════════════════════════════════
The following NoSuchMethodError was thrown during performLayout():
'<Unexpected Null Value>'
method not found
Receiver: null
Arguments: []
The relevant error-causing widget was
Html
lib\…\chat\panel_chat_entry.dart:114
When the exception was thrown, this was the stack
...
I can also confirm it was working before with version 0.11.0 still with Flutter SDK 1.17.3.
NicolasDionB
on 10 Jun 2020
I'm having a hard time getting my build process working and I don't have too much time this weekend and have other issues that need my attention. If anyone can submit a PR to fix this it would me much appreciated and I would make it a priority to get it merged.
One thing I did notice is that the line it is complaining about is the line that holds a Text.rich constructor, so maybe there is something being deprecated within the Text class in the newer versions of Flutter, or maybe there is a slight API change. It is possible this could be a Flutter issue.
ryan-berger
on 13 Jun 2020
+1. I get this error (or it looks like the same) in all cases. here is the stack trace:
https://gist.github.com/OlegBrony/eb153dcc604c26e02a1cb8c20908aeef
I got code from package example:
const htmlData = """
<div>qweqwe</div>
""";
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: AppBar(
title: Text('flutter_html Example'),
centerTitle: true,
),
body: SingleChildScrollView(
child: Html(
data: htmlData,
//Optional parameters:
),
),
);
}
}
OlegBrony
on 15 Jun 2020
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Most helpful comment
I'll take a look at this sometime this week as it looks critical. From what I understand, we don't officially Web, but if this is the only thing holding us from fully supporting Flutter Web, I don't mind supporting it