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I'm using the 3.1.0-beta version of ZXing.Net.Mobile and ZXing.Net.Mobile.Forms in my Xamarin Forms 5 app.

Everything is working fine on Android but on iOS, it just doesn't seem to scan at all on an actual device connected to my PC via USB. I also packaged the app and uploaded it for TestFlight testing. When I test it as a fully installed app on my iPhone, it actually crashes the app all together.

My research shows this may happen due to permission issues. I do have the following in Info.plist:

<key>NSCameraUsageDescription</key>
<string>MyApp would like to access your camera</string>
<key>NSMicrophoneUsageDescription</key>
<string>MyApp would like to access your microphone</string>
<key>NSPhotoLibraryAddUsageDescription</key>
<string>MyApp would like to access your photo library</string>

Though it's not working on my iPhone Xs, the same setup is working just fine on both Android emulator and a cheap LG phone.

There's not much code to show here but here's what I have in my XAML file:

<zxing:ZXingScannerView
   IsScanning="True"
   OnScanResult="OnScanCompleted"/>

I also want to mention that my app uses the MVVM pattern so here's what I've done to wire things: the OnScanCompleted is in XAML page's code behind that looks like this:

private async void OnScanCompleted(ZXing.Result result)
{
    await _vm.On_Code_Scanned(result.Text);
}

So, I call a method in my view model from OnScanCompleted which is in code behind.

And the method in view model is fairly simple:

public async Task On_Code_Scanned(string code)
{
   // Process code
}

Any idea how to fix this issue?

UPDATE:

I started a fresh new Xamarin Forms app. I then added ZXing.NetMobile and ZXing.Net.Mobile.Forms and nothing else. When I test scanning a QR code on my iPhone Xs, it still fails. So, it looks like this particular libary just doesn't work on iOS at all

Sam
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  • What is being reported in the iPhone Debug Log/Console? and have you tried using `AVCaptureSession` – SushiHangover Apr 23 '22 at 09:35
  • In your AppDelegate's FinishedLaunching (..) implementation, call: ZXing.Net.Mobile.Forms.iOS.Platform.Init(); – Adrain Apr 25 '22 at 02:11
  • @AdrainZhu-MSFT Already doing that – Sam Apr 25 '22 at 03:52
  • It seems related to the version of zxing, try down downgrade to 2.4.1 – Adrain Apr 25 '22 at 05:27
  • @AdrainZhu-MSFT Tried that too but it opens up a whole new can of worms. There are all kinds of compatibility issues with Xamarin Forms. – Sam Apr 25 '22 at 12:31
  • accroding to this issue https://github.com/Redth/ZXing.Net.Mobile/issues/967 if you deploy on windows, you can try it on mac – Adrain Apr 26 '22 at 08:47
  • I actually packaged the app and installed it on my iPhone through TestFlight and it totally crashed the app. So not working at all on iOS but on Android, it's all fine. – Sam May 10 '22 at 15:38
  • I have the same issue as yours, it was working well for a year, but few days ago when user updated to the latest ios version, then it crash when the apps tried to use the camera for barcode scan, i am using the same library as you. If you found the solution elsewere please post it here too, as i need the answer too :D thanks in advance (i commented in order to follow this post) – paiseha May 20 '22 at 07:50

3 Answers3

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I had the same issue.

The only thing I did was that I've changed the Xamarin.IOS to the latest version (16.0.0.75).

By using Visual Studio => go to Help/Check for Updates

It solved the problem.

Sandor
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1

i had similar issue, it was working for more than a year then all of sudden all my users complaint its not working anymore, after ios update. the apps just crash whenever it tried to call the barcode scanning camera using zxing.

the solution was easy in my case, just recompile it using latest xamarin.ios version. just need to make sure the version is up to date

paiseha
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  • Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jun 08 '22 at 04:30
0

I also faced this issue and found the solution.

Instead of using metadataoutput.AvailableMetadataObjectTypes, you need to set all code types in an array of AVMetadataObjectType, for ex:

AVMetadataObjectType.EAN8Code | AVMetadataObjectType.EAN13Code | 
AVMetadataObjectType.Code39Code | AVMetadataObjectType.Code128Code |......
Ricardo Dias Morais
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Sheetal
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