dismissviewcontroller:aimated:completion: in captureresult:result: crashes app

[baze]

i started integrating zxingobjc into my app by using the example code and it works well, but I want to dismiss the Scanner view controller when I actually get a result while scanning, so I stop the capture and call dismissviewcontroller:animated:completion, but right after the controller is dismissed, the app crashes.

i get some messages from libobjc.A.dylib`objc_msgSend: which i don't understand, but I guess it might be a threading error. not sure though.

i also tried making sure to dismiss from the main thread, but it didn't help. is this a known issue and do you have any tips for me as how to dismiss the scanner view controller correctly when it got a result?

[baze]

ok, actually it is due to overreleasing zxcapture. when I enable zombie objects, I get this error:

*** -[ZXCapture release]: message sent to deallocated instance 0x22364c10

does zxingobjc not work with ARC projects yet?

[benvium]

I'm getting the same issue. Unfortunately this is making ZXingObjC of no use to me. It looked very promising too!

[benvium]

.. ok I believe I've sorted it out, simply by marking my ViewController .m file compiled without ARC. Haven't had any crashes yet..

[rtiago42]

I got the some problem on an app I'm developing.

I was unable to identify the culprit, but I'm convinced the problem happens during the deallocation. While trying to pin point it, I came to the conclusion (albeit being unable to verify it) that the crash happens on the garbage collector as a cause of over releasing.

**
As a workaround I created a static ZXCapture and re-use it, instead of letting it be dealloced.

[percysnoodle]

Same here. The crash is in AVFoundation__74-[AVCaptureVideoDataOutput _AVCaptureVideoDataOutput_VideoDataBecameReady]_block_invoke_0: so it looks like there's a AVCaptureVideoDataOutput with the ZXCapture or one of its properties as a delegate that isn't being nilled out in dealloc.

[kilink]

I found that you need to remove the capture.layer from your view before calling dismissViewControllerAnimated:completion:. Here's what I do when dismissing the view controller:

[self.capture.layer removeFromSuperlayer];
[self.capture stop];
[self dismissViewControllerAnimated:YES completion:nil];

[baze]

Nice, that works fine!
Thank you very much.

On 01.02.2013, at 16:06, Patrick Strawderman notifications@github.com wrote:

I found that you need to remove the capture.layer from your view before calling dismissViewControllerAnimated:completion:. Here's what I do when dismissing the view controller:

[self.capture.layer removeFromSuperlayer];
[self.capture stop];
[self dismissViewControllerAnimated:YES completion:nil];
—
Reply to this email directly or view it on GitHub.

[christosc]

Thanks very much! It works!

[BonnieBonfire]

Thank you.

[aceontech]

Has this fix been pushed to the Cocoapods version of ZXingObjC, because I'm still encountering this issue when I include ZXing 2.1.0 via Cocoapods? Thanks!

[jxdwinter]

+1

[Vladlex]

I'm on a 2.2.2 version and this bug still happens (iOS7, iPhone 4).
But "removeFromSuperlayer" works perfectly for me.

[cwalcott]

Are you seeing the "message sent to deallocated instance" error on [ZXCapture release]?

[zhenja]

Same for me, working with version 2.2.2 on iOS 7.0.4 getting this error message:
-[ZXCapture release]: message sent to deallocated instance
But can't reproduce it :(

[cwalcott]

I've just pushed (TheLevelUp/ZXingObjC@d9e3d23) a major cleanup to ZXCapture. I hope it will get rid of any remaining memory issues, and if not, at least make them easier to debug.

[davidfrasch]

I think the Problem is still available with ne newest Version and iOS 7.1. After I scan 1-10x QR-Codes fast behind each other, i getting an EXC_BAD_ACCESS Error. After using Instruments(zombie) I recognize a ZXCapture-Zombie. After implementing the short Code part above:
[self.capture.layer removeFromSuperlayer];
[self.capture stop];

it seems to work fine! Thank you very much!

[lugede]

Thank u very much.