Null check operator used on a null value in PlatformView.

flutter/packages/flutter/lib/src/widgets/platform_view.dart

Line 898 in 7fe3565

setState(() { _platformViewCreated = true; });

setState is called when element is null.

Stacktrace received on crashlytics:

Non-fatal Exception: io.flutter.plugins.firebase.crashlytics.FlutterError: Null check operator used on a null value. Error thrown null.
       at State.setState(framework.dart:1108)
       at _PlatformViewLinkState._onPlatformViewCreated(platform_view.dart:889)
       at AndroidViewController.create(platform_views.dart:752)

@rahul-bst

@rahul-bst
Can you provide your flutter doctor -v and possibly a complete minimal reproducible code sample that would throw this exception ?

Hi,

The app is built with Github Action on random remote machine where we use flutter v2.2.1. We have crashlytics added where we got this issue reported.

flutter doctor of my machine doesn't matter much but here it goes:

[✓] Flutter (Channel unknown, 2.2.1, on macOS 11.6.2 20G314 darwin-x64, locale en-GB)
    • Flutter version 2.2.1 at /Users/rahul/Library/flutter/flutter221/flutter2
    • Framework revision 02c026b03c (8 months ago), 2021-05-27 12:24:44 -0700
    • Engine revision 0fdb562ac8
    • Dart version 2.13.1

[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0-rc4)
    • Android SDK at /Users/rahul/Library/Android/sdk
    • Platform android-31, build-tools 31.0.0-rc4
    • ANDROID_HOME = /Users/rahul/Library/Android/sdk
    • Java binary at: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java
    • Java version Java(TM) SE Runtime Environment (build 1.8.0_201-b09)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 13.0, Build version 13A233
    • CocoaPods version 1.11.2

[!] Android Studio (version 2020.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    ✗ Unable to find bundled Java version.
    • Try updating or re-installing Android Studio.

[✓] IntelliJ IDEA Community Edition (version 2021.2.3)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart

[✓] VS Code (version 1.63.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.26.0

[✓] Connected device (1 available)
    • macOS (desktop) • macos • darwin-x64 • macOS 11.6.2 20G314 darwin-x64
    ! Error: Rahul’s iPhone is not connected. Xcode will continue when Rahul’s iPhone is connected. (code -13)

! Doctor found issues in 1 category.

I looked at the source code in master branch as well and it definitely has potential for the bug. By the time, _onPlatformViewCreated is called, the Widget might be disposed leading to above mentioned error.

I don't have steps to reproduce it right now, but if the explanation is insufficient I can come up with set of steps to reproduce it.

Thanks for the reply.

Regards,
Rahul K

Thanks for the update. It could be a possibililty that the widget has gone away by the time you call setState?
You can check https://master-api.flutter.dev/flutter/widgets/State/mounted.html and confirm the widget is mounted for the first time but the main thing to confirm if the widget is still mounted after it goes past any async calls ?

@darshankawar

@darshankawar
We have the coming up on Sentry/Crashlytics as well on Flutter 2.8.1 (stable).

The problem is obvious by just static code analyzing.

PlatformView's created callbacks get called from here:

flutter/packages/flutter/lib/src/services/platform_views.dart

Line 775 in 7fe3565

callback(viewId);

This is an async function with an await in it. It's normal for an element to be in a different state before and after an await happens and a mounted check is always required before calling setState after an await like this.

The problem stems from the fact that this issues's crash line
https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/widgets/platform_view.dart#L898
expects this to only ever be called when not disposed (which it should not).

Without additional information, we are unfortunately not sure how to resolve this issue. We are therefore reluctantly going to close this bug for now.
If you find this problem please file a new issue with the same description, what happens, logs and the output of 'flutter doctor -v'. All system setups can be slightly different so it's always better to open new issues and reference the related ones.
Thanks for your contribution.

@darshankawar

@darshankawar
Why did actions close this automatically?

We've given a direct view in to the problem and how to fix it.

@Moncader

@Moncader
Since this issue has waiting label and there wasn't any response from original author for 21 days, the bot automatically closed it.
But I am reopening this and labeling based on your findings.

Don't call `PlatformViewCreatedCallback`s after `AndroidViewControlle…

Improve CupertinoContextMenu to match native more (#117698)

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.

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Null check operator used on a null value in PlatformView. #96384

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Null check operator used on a null value in PlatformView. #96384

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darshankawar commented on Jan 10, 2022

rahul-bst commented on Jan 10, 2022

darshankawar commented on Jan 11, 2022

Moncader commented on Jan 12, 2022

github-actions commented on Feb 1, 2022

Moncader commented on Feb 1, 2022

darshankawar commented on Feb 1, 2022

github-actions commented on Mar 3, 2023

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