[BUG] App crash when returning to it

[hsson]

Describe the bug
After just having used the scanning functionality, then closing the app, and the re-opening the app, I encountered the following exception:

java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:503)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.reflect.InvocationTargetException        at java.lang.reflect.Method.invoke(Method.java:-2)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: android.hardware.camera2.CameraAccessException: CAMERA_DISCONNECTED (2): checkPidStatus:1708: The camera device has been disconnected
        at android.hardware.camera2.CameraManager.throwAsPublicException(CameraManager.java:728)
        at android.hardware.camera2.impl.ICameraDeviceUserWrapper.waitUntilIdle(ICameraDeviceUserWrapper.java:179)
        at android.hardware.camera2.impl.CameraDeviceImpl.waitUntilIdle(CameraDeviceImpl.java:1135)
        at android.hardware.camera2.impl.CameraDeviceImpl.configureStreamsChecked(CameraDeviceImpl.java:436)
        at android.hardware.camera2.impl.CameraDeviceImpl.createCaptureSessionInternal(CameraDeviceImpl.java:662)
        at android.hardware.camera2.impl.CameraDeviceImpl.createCaptureSession(CameraDeviceImpl.java:510)
        at uk.co.brightec.kbarcode.camera.Camera2Source.createCaptureSession$kbarcode_release(Camera2Source.kt:121)
        at uk.co.brightec.kbarcode.camera.Camera2Source$start$1.onOpened(Camera2Source.kt:55)
        at android.hardware.camera2.impl.CameraDeviceImpl$1.run(CameraDeviceImpl.java:143)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6718)
        at java.lang.reflect.Method.invoke(Method.java:-2)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: android.os.ServiceSpecificException: checkPidStatus:1708: The camera device has been disconnected
        at android.os.Parcel.createException(Parcel.java:1964)
        at android.os.Parcel.readException(Parcel.java:1918)
        at android.os.Parcel.readException(Parcel.java:1868)
        at android.hardware.camera2.ICameraDeviceUser$Stub$Proxy.waitUntilIdle(ICameraDeviceUser.java:599)
        at android.hardware.camera2.impl.ICameraDeviceUserWrapper.waitUntilIdle(ICameraDeviceUserWrapper.java:177)
        at android.hardware.camera2.impl.CameraDeviceImpl.waitUntilIdle(CameraDeviceImpl.java:1135)
        at android.hardware.camera2.impl.CameraDeviceImpl.configureStreamsChecked(CameraDeviceImpl.java:436)
        at android.hardware.camera2.impl.CameraDeviceImpl.createCaptureSessionInternal(CameraDeviceImpl.java:662)
        at android.hardware.camera2.impl.CameraDeviceImpl.createCaptureSession(CameraDeviceImpl.java:510)
        at uk.co.brightec.kbarcode.camera.Camera2Source.createCaptureSession$kbarcode_release(Camera2Source.kt:121)
        at uk.co.brightec.kbarcode.camera.Camera2Source$start$1.onOpened(Camera2Source.kt:55)
        at android.hardware.camera2.impl.CameraDeviceImpl$1.run(CameraDeviceImpl.java:143)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6718)
        at java.lang.reflect.Method.invoke(Method.java:-2)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

I believe this is rather rare though, but it might be good if you handled this some better way that doesn't cause the app to crash.

To Reproduce
Steps to reproduce the behavior:
Close app, and then re-open it. Doesn't happen all the time though.

Expected behavior
I expected the app to re-open with the camera view and the scanning started as normal. This is what happens most of the time, except this one time when I got the exception.

Screenshots
N/A

Smartphone (please complete the following information):

• Device: Google Pixel 2 XL
• OS: Android 9, API 28

Additional context
None

[hsson]

Actually, this happens quite often. If I simply leave the scanner running, lock my phone and leave it locked for a few seconds, then unlock it, this happens.

[alistairsykes]

Thanks for reporting @hsson. Have you found this on any other devices too? My aim would certainly be for this to be reported through the OnCameraErrorListener

[hsson]

I can reproduce this in the emulator as well! Simply by leaving the scanner running, locking the phone (the emulators power button), leaving it locked for a few seconds, then unlocking again. Are you saying it's possible for me to catch this error and handle it myself through the OncameraErrorListener? :)

[hsson]

I tried setting the OnCameraErrorListener on my BarcodeView in my fragment's onResume method, but this didn't catch the error.

[alistairsykes]

Sorry, I mean my intention for fixing this issue would be to make it return in the OnCameraErrorListener. I will take a look this.

[hsson]

Okay, sounds great! :)

[alistairsykes]

I haven't been able to create this, but if I create PR for what I think the changes should be @hsson would you be able to see if they are suitable for your needs?

[hsson]

Hm okay! Well that would be great, I can test it out. I could also try and create an example app that recreates the issue.

[hsson]

I did some more digging, and I'm starting to suspect that this is caused by the fact that I'm calling start() on my BarcodeView unconditionally in my fragments onResume(), I did this as the camera for some reason sometimes wouldn't start automatically either on resuming to the fragment or after having granted permissions.

[alistairsykes]

Oh ok interesting. We have just merged in a pull request which should catch the CameraAccessException and return it in the OnCameraErrorListener. If you wouldn't mind checking it reports the exception rather than crashing that would be great, even if there is another issue somewhere, it would be good to see if this resolves that.

Are you able to provide your implementation to show the camera not starting? How have you chosen to implement the library: lifecycle aware or manual; xml or programmatic? Did you follow a particular sample?

[alistairsykes]

@hsson

[hsson]

Okay I've solved the issue on my end now! I accidentally and incorrectly called ActivityCompat.requestPermissions instead of calling requestPermissions directly on my fragment. This meant that my callback never got called, so my view_barcode.start() was never called. What a silly thing... I implemented the library lifecycle aware using XML. And like I said in my last comment, it appears that my calls to start() in my onResume() is what caused the crashes, but this is not needed anymore.

[hsson]

Sorry for the headache! :)

I'll see if I can get around to verifying that your pull request fixes the original issue as well!

[alistairsykes]

@hsson Ahh yes that is a silly gotcha. I'm glad you found the issue.

Interestingly, even adding start() in onResume() doesn't cause that crash for me.