[Android] App shows black screen after being in the background.

[thomasaldershof]

Steps to Reproduce

It seems to happen on different Flutter apps. Open a Flutter app, go to your home screen and open some other apps. Wait for some time and open the Flutter app again. There is now a chance that the app shows a black screen. No Appbar, BottomBar or any widget. It happens pretty frequently if you know how to trigger it.

The app seems to respond to user interaction, just had it on the debugger but there is no useful information, no errors, no exceptions thrown. Moving to the android recents screen and returning to the app fixes this. I haven't tried to do this with iOS.

Was able to reproduce this on some older installed apps, app created with Flutter stable 2.5.3 and the latest beta build (2.7.0 iirc).

I can't really create an app sample because it is pretty hard to know when it exactly happens because it is not guaranteed to happen. It does occur on multiple devices and some users have noticed it too. No data on crashlytics or runguarded zone.

[✓] Flutter (Channel stable, 2.5.3, on Microsoft Windows [Version 10.0.22000.282], locale en-NL)
    • Flutter version 2.5.3 at C:\src\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 18116933e7 (3 weeks ago), 2021-10-15 10:46:35 -0700
    • Engine revision d3ea636dc5
    • Dart version 2.14.4

[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
    • Android SDK at C:\Users\dxzds\AppData\Local\Android\sdk
    • Platform android-31, build-tools 31.0.0
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7249189)
    • All Android licenses accepted.

[✓] Chrome - develop for the web
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[✓] Android Studio (version 2020.3)
    • Android Studio at C:\Program Files\Android\Android Studio
    • 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
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7249189)

[✓] VS Code (version 1.61.2)
    • VS Code at C:\Users\dxzds\AppData\Local\Programs\Microsoft VS Code
    • Flutter extension can be installed from:
      🔨 https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[✓] Connected device (3 available)
    • IN2023 (mobile) • 192.168.0.165:40423 • android-arm64  • Android 11 (API 30)
    • Chrome (web)    • chrome              • web-javascript • Google Chrome 95.0.4638.69
    • Edge (web)      • edge                • web-javascript • Microsoft Edge 95.0.1020.44

[maheshj01]

Hi @vanth0me, Thanks for filing the issue.

I can't really create an app sample because it is pretty hard to know when it exactly happens because it is not guaranteed to happen. It does occur on multiple devices and some users have noticed it too. No data on crashlytics or runguarded zone.

Can you please share some more details

• How long have you put the app in the background?
• which Android devices reproduce the issue?
• Does this reproduce on an emulator too or only on a real device?
• Can you please also check if this happens with a specific flutter project or a newly created flutter project too?

[thomasaldershof]

Thank you for your response!
I think usually happens after 5+min, but I've had it sooner. From the devices I know it is my OnePlus 8 Pro, Samsung S10 and the emulator too. I recreated the project and moved the code and the same thing happened. As I have said older self made apps also show this. I don't know if I can trigger it with the base app. I will have to try that later today.

[maheshj01]

I don't know if I can trigger it with the base app. I will have to try that later today.

Sure please verify and let us know and also please check the android version of the devices to make sure if this is/ is not related to the OS version.

[thomasaldershof]

Yes will do. My emulator is running Android 12 and the devices are running Android 11.

[thomasaldershof]

I am, for now, at least unable to trigger a black screen in the New Flutter Project app. I wonder if it has something to do with more memory usage.

[maheshj01]

@vanth0me without any code sample or logs its not possible to find the cause of the issue.

I am, for now, at least unable to trigger a black screen in the New Flutter Project app. I wonder if it has something to do with more memory usage.

Are there any logs that you can share?
Is it possible for you to share a repository containing the reproducible code?