Xamarin Forms (Android) - JNIEnv.cs not found

Séb Carré (Glanum) 21

Hello ! I have updated Xamarin Forms and I have an issue right now. After build was done, at launch, VS says that JNIEnv.cs was not found. How I can fix this issue ? Thanks !

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 68,656 Reputation points Microsoft Vendor

2021-12-21T05:23:18.323+00:00

Can you share your VS version and all of install nuget packages version? You can close VS and update your VS the latest version, then open the project folder, delete all of bin and obj folders(xxx.Android also have bin and obj folder).In the end. open your project. clean and rebuild your application.
Joe Sauve 1 Reputation point

2021-12-28T17:52:13.947+00:00

I'm seeing the same issue when debugging on either my Pixel 4a or an Android 11 emulator. Clearing all bin & obj folders with 'git clean -fdx' made no change in the behavior.

Environment details here:
https://gist.github.com/jsauve/af7386409c42b9690c76702ff9d78f91

I'm using the Preview version of VS for Mac 2022.

Notice in the screenshot that the debugger is resolving a breakpoint in JNIEnv.cs, even though there are no breakpoints active in the "Breakpoints" window in Visual Studio. Also strange is that it's resolving a filepath that does not exist on my dev machine's filesystem:

"/Users/builder/azdo/_work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNIEnv.cs:124".

"/Users/builder" is not a user that exists on my local filesystem.

JNIEnv.cs is a part of Xamarin Android, and is not a local source file of mine:
https://github.com/xamarin/xamarin-android/blob/main/src/Mono.Android/Android.Runtime/JNIEnv.cs

This is the apparent offending line in JNIEnv.cs:
https://github.com/xamarin/xamarin-android/blob/main/src/Mono.Android/Android.Runtime/JNIEnv.cs#L124

So, why is there a breakpoint being resolved in that file?
Joe Sauve 1 Reputation point

2022-01-23T08:49:34.157+00:00

@Leon Lu (Shanghai Wicresoft Co,.Ltd.) Unlike the other user (SbCarrGlanum-9562), I don't have the luxury of going back to an earlier version of VS for Mac. My solution includes a .NET 6 -based
Web API + a Xamarin Forms project. I'd really like for this issue to be investigated.
Rob Caplan - MSFT 5,412 Reputation points Microsoft Employee

2022-01-24T18:14:51.82+00:00

Hi Joe,

VS for Mac 2022 and .Net 6 for Android are still in preview and not yet supported on Q&A.

If you have a problem specific to VS for Mac 2022 (preview) please use the feedback link in VS's menubar.

1 answer

Séb Carré (Glanum) 21 Reputation points

2021-12-29T08:16:18.983+00:00

Hello ! Sorry for not reponding earlier.

Yes I have install VS 2022 For Mac (Preview 4). Just like you I had this problem with JNIEnv.cs.

I've resolve this issue by just go back to the older VS for Mac i had on my machine and search for new updates.

Xamarin.iOS and Xamarin.Android SDK were updated and I had no more issues with that.

I can now run VS 2022 For Mac without this issue.

Hope this is helping you !
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Leon Lu (Shanghai Wicresoft Co,.Ltd.) 68,656 Reputation points Microsoft Vendor

2021-12-30T08:47:40.343+00:00

Thanks for your sharing.
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