Camera permission issue on Android

[DerProfessor]

There exists an issue with the camera permission on Android that causes the main app to crash. If this library is integrated in a Flutter app and used on Android to scan documents with the provided document scanner (through MLKit/Play services) a crash occurs if a user selects the one-time permission for the camera and scans documents for more than one minute.

The problem is that this library requests the camera permission. If the app is used on Android and the provided document scanner from MLKit is used, the permission itself is provided through Play services. I tested this by removing the permission request in this library. If a user selects the one-time permission for the camera and the document scanner activity starts, a behavior begins, that is best described in this issue by fabiendem (react-native).
TLDR: The main app is set into background and after one minute the Android OS revokes the camera permission and kills the main app process. This is not immediately noticed due to the document scanner still being in the foreground. It is not a bug but intended behavior on Android. This is the logcat output when the one-time permission expires and is revoked by the operating system:

2025-11-24 15:28:57.188  1386-1386  OneTimePer...serManager system_server                        I  One time session expired for com.example.frontend (10327). deviceID 0
2025-11-24 15:28:57.220 27035-27404 Permission...erviceImpl com....android.permissioncontroller  I  Permission grant result requestId=-1688396230408645273 callingUid=10327 callingPackage=com.example.frontend permission=android.permission.CAMERA isImplicit=false result=15
2025-11-24 15:28:57.231  1386-1550  ActivityManager         system_server                        I  Killing 27093:com.example.frontend/u0a327 (adj 850): one-time permission revoked

Currently my workaround is to only request the camera permission if the app runs on iOS. I cannot test this platform so I keep the check and assume most Android users have Play services installed.

I am not sure what alternative approach might be good. We could move the permission request to the native code itself and remove it on the Flutter end, only keeping the platform method call.

[vicajilau]

@DerProfessor Could you retry using 1.4.0 version? We just updated the MLKit dependency today 🚀

[DerProfessor]

Hi vicajilau,

thank you for the update of this package. I updated to version 1.4.0.

Unfortunately, the issue still persists. I don't believe the reason lies in the MLKit dependency but rather in the permission request on the Flutter side inside this package, like I explained in my first post. Android performs intended behavior here when it kills the main app process after revoking the one-time permission for the camera. This happens if a user stays longer than one minute inside the document scanner, for example collecting multiple images.

I think there are two ways to handle this:

1. The simplest way would be to skip the permission check for Android platforms and only do it for iOS platforms. The Play services always have the camera permission. If a user tries to remove it through the Settings app, Android warns that this action could cause functions to break. Unfortunately, this approach would cause the fallback scanner to never work.
2. Move the entire permission check to native code side. We can always check the permission on iOS. We can check the permission on Android only if Play services and therefore MLKit are unavailable. In this case we could request the permission in order to use the Fallback scanner.

[daniJimen]

@DerProfessor Good afternoon, I've been testing the application, even leaving it open for 5 minutes with the camera, without the error you mentioned occurring. However, I agree with you that on Android, using MTKit, the permission request isn't necessary, so I've removed them directly. I would suggest that once the pull request is approved, you could try it to see if your issue has been resolved. I haven't been able to replicate your issue, so I'll leave the pull request here: #121

[DerProfessor]

Hi @daniJimen,

thank you for opening a pull request regarding this.

The issue only occurs if a user grants the one-time camera permission ("Only this time") and collects document scans using the MLKit document scanner longer than one minute. Have you tested this scenario aswell?

If the user grants for example the "While using this app" permission, the issue does not occur - at least not with our test device and the Android emulator.

Granting the "Only this time" permission and staying inside the MLKit document scanner for more than one minute causes the Android OS permission revocation and termination of my main Flutter app silent in the background. I noticed this when finished scanning and returned to my Flutter app which restarts in this scenario.

[daniJimen]

Hi @DerProfessor , in my case, I tested leaving the MLKit document scanner camera open for up to 5 minutes without my device revoking permissions or closing the app. This might be related to the Android version you're running. Could you share the version number? I'm testing on Android 13. In any case, with the change I added in the PR, it will no longer request these permissions, as they are no longer necessary, and therefore your problem should disappear.

[DerProfessor]

Hi @daniJimen,
the Android emulators I use run Android 15 and 16. The physical test device I have runs Android 16.
I could test it on older Android versions inside the emulator.

[DerProfessor]

Hi @daniJimen,
I tested the app in an emulator running Android 13. I could reproduce the behaviour with the one-time permission related app crash on it. I believe the behaviour does not seem to be related to the Android version.