EXCEPTION CAUGHT BY WIDGETS LIBRARY

[benedicte69]

Performing hot restart...
Restarted app in 1 288ms.
I/flutter (10540): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (10540): The following assertion was thrown building MyApp(dirty, state: _State#fe0a2):
I/flutter (10540): type 'List<dynamic>' is not a subtype of type 'List<Widget>'
I/flutter (10540): 
I/flutter (10540): Either the assertion indicates an error in the framework itself, or we should provide substantially
I/flutter (10540): more information in this error message to help you determine and fix the underlying cause.
I/flutter (10540): In either case, please report this assertion by filing a bug on GitHub:
I/flutter (10540):   https://github.com/flutter/flutter/issues/new
code used:
[error_radios.txt](https://github.com/flutter/flutter/files/2321780/error_radios.txt)

[zoechi]

Please add the output of flutter doctor -v
and more instructions about how to reproduce.

Looks like a dup of dart-lang/sdk#33076

[benedicte69]

Thanks @zoechi, I have been said "Dart 2 uses what is call "strong mode" flag by default, in other words, you need to avoid to not properly type your variables." If you want to reproduce the error just paste the code used which is in the error_radios.txt I joined at the end of my initial post.

[benedicte69]

a sample of flutter doctor -v

C:\Users\TOTO>flutter doctor -v
[√] Flutter (Channel beta, v0.5.1, on Microsoft Windows [version 10.0.17134.228], locale fr-FR)
• Flutter version 0.5.1 at C:\Users\TOTO...\flutter
• Framework revision c7ea3ca (3 months ago), 2018-05-29 21:07:33 +0200
• Engine revision 1ed25ca
• Dart version 2.0.0-dev.58.0.flutter-f981f09760

[√] Android toolchain - develop for Android devices (Android SDK 28.0.2)
• Android SDK at C:\Users\TOTO...
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-28, build-tools 28.0.2
• ANDROID_HOME = C:\Users\TOTO...
• Java binary at: C:\Users\TOTO...\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)
• All Android licenses accepted.

[√] Android Studio (version 3.1)
• Android Studio at C:\Users\TOTO...
• Flutter plugin version 27.1.1
• Dart plugin version 173.4700
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)

[√] Connected devices (1 available)
• Android SDK built for x86 • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)

• No issues found!

C:\Users\TOTO>

[benedicte69]

Hope it can help, I am too much beginner to understand. But, apparently before this revision c7ea3ca things were different and it was not necessary to change List radiosList = new List(); by List radiosList = List();

[zoechi]

Because your log was not wrapped in ``` the <dynamic> and `` parts were not visible.
This makes it clear now that this issue is not related to #33076

[zoechi]

You just need to change

List radiosList = new List();

to

List radiosList = new List<Widget>();

or

List<Widget> radiosList = new List<Widget>();

or

List<Widget> radiosList = [];

or

var /* or final */ radiosList = <Widget>[];

[benedicte69]

yes, thank you. Can we expect a clearer error message when it occurs? Le lundi 27 août 2018 à 08:10:05 UTC+2, Günter Zöchbauer <[email protected]> a écrit : You just need to change List radiosList = new List(); to List radiosList = new List<Widget>(); or List<Widget> radiosList = new List<Widget>(); or List<Widget> radiosList = []; or var /* or final */ radiosList = <Widget>[]; — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[zoechi]

Any suggestion? I found the error message is clear.

[benedicte69]

Oh sorry, I am not meaning your answer is not clear, I just mean that 'EXCEPTION CAUGHT BY WIDGETS LIBRARY' can be misleading for beginners. Perhaps in the future as soon as your code will be wrong as mine was, AS will tell you that your variable should be more precise.Anyway, thank you very very much for your help :) Le lundi 27 août 2018 à 11:11:34 UTC+2, Günter Zöchbauer <[email protected]> a écrit : Any suggestion? I found the error message is clear. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[zoechi]

I see what you mean.

EXCEPTION CAUGHT BY WIDGETS LIBRARY

Is reported because Flutter acts as a framework that calls your code and it runs into an error when doing that.

I meant

type 'List' is not a subtype of type 'List'

should give a pretty good hint at what is wrong.
As you see from my answer above there are many valid options and it's hard for the compiler to make a more specific suggestion because the compiler can't know your intention.

[benedicte69]

Many thanks for this reassuring and clear answer. Up to me now to learn deeper. I think you really answered to all my beginner's concerns and reactions. The thread can be peacefully closed now :). Le lundi 27 août 2018 à 12:06:25 UTC+2, Günter Zöchbauer <[email protected]> a écrit : I see what you mean. EXCEPTION CAUGHT BY WIDGETS LIBRARY Is reported because Flutter acts as a framework that calls your code and it runs into an error when doing that. I meant type 'List' is not a subtype of type 'List' should give a pretty good hint at what is wrong. As you see from my answer above there are many valid options and it's hard for the compiler to make a more specific suggestion because the compiler can't know your intention. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[zoechi]

Great!

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.