Xamarin-android: Issue with R8 Compilation

Created on 25 Mar 2020 · 10Comments · Source: xamarin/xamarin-android

In my app I am using Zebra EMDK library for integrating Barcode Scanner.
In order to Creating a common Application to run on Zebra and Non-Zebra devices I am adding this line of code in Android Manifest
<uses-library android:name="com.symbol.emdk" android:required="false" /> I have implemented this as per Zebra documentation

The issue I am facing is, when I enable R8, D8 compilation it is not building the application and I am getting the below error

R8: Error: Compilation can't be completed because some library classes are missing.

Android Build configuration of the app is

Error List

I am attaching the source code of the same for your reference in below link.

Code

App+Library Build

Source

rkshnair

Most helpful comment

we at Zebra Techsupport are made aware of this issue with R8 warnings and EMDK Nuget package

we have approached our Engineering EMDK team around this and will post back an message here once we have their opinion.

internally we have an Engineering ticket with refernce "SPR39963"

xbr786 on 13 May 2020

👍3

All 10 comments

I did a bit of investigation.

Task "DetermineJavaLibrariesToCompile" (TaskId:489)
  Task Parameter:
      MonoPlatformJarPaths=
          /Users/dean/Documents/Sandbox/Xamarin/xamarin-android/bin/Debug/lib/xamarin.android/xbuild-frameworks/MonoAndroid/v10.0/mono.android.jar
          /Users/dean/Documents/Sandbox/Xamarin/xamarin-android/bin/Debug/lib/xamarin.android/xbuild/Xamarin/Android/java_runtime_fastdev.jar (TaskId:489)
  Task Parameter:
      JavaLibraries=
          /Users/dean/.nuget/packages/xamarin.androidx.annotation/1.1.0/buildTransitive/monoandroid90/../../jar/androidx.annotation.annotation.jar
                  AndroidXSkipAndroidXMigration=true
          /Users/dean/.nuget/packages/xamarin.androidx.collection/1.1.0/buildTransitive/monoandroid90/../../jar/androidx.collection.collection.jar
                  AndroidXSkipAndroidXMigration=true
          /Users/dean/.nuget/packages/xamarin.androidx.lifecycle.common/2.2.0/buildTransitive/monoandroid90/../../jar/androidx.lifecycle.lifecycle-common.jar
                  AndroidXSkipAndroidXMigration=true
          /Users/dean/.nuget/packages/xamarin.androidx.arch.core.common/2.1.0/buildTransitive/monoandroid90/../../jar/androidx.arch.core.core-common.jar
                  AndroidXSkipAndroidXMigration=true
          obj/Debug/androidx/jl/2bbedeb9-4617-4e4e-b1d3-8d60e634827a.jar (TaskId:489)
  Task Parameter:
      LibraryProjectJars=
          obj/Debug/lp/61/jl/classes.jar
          obj/Debug/lp/59/jl/classes.jar
          obj/Debug/lp/92/jl/classes.jar
          obj/Debug/lp/66/jl/classes.jar
          obj/Debug/lp/68/jl/classes.jar
          obj/Debug/lp/57/jl/classes.jar
          obj/Debug/lp/69/jl/classes.jar
          obj/Debug/lp/58/jl/classes.jar
          obj/Debug/lp/67/jl/classes.jar
          obj/Debug/lp/93/jl/classes.jar
          obj/Debug/lp/94/jl/classes.jar
          obj/Debug/lp/60/jl/classes.jar
          obj/Debug/lp/0/jl/formsviewgroup.jar
          obj/Debug/lp/89/jl/classes.jar
          obj/Debug/lp/73/jl/classes.jar
          obj/Debug/lp/87/jl/classes.jar
          obj/Debug/lp/80/jl/classes.jar
          obj/Debug/lp/74/jl/classes.jar
          obj/Debug/lp/1/jl/com.symbol.emdk.jar
          obj/Debug/lp/75/jl/classes.jar
          obj/Debug/lp/81/jl/classes.jar
          obj/Debug/lp/86/jl/classes.jar
          obj/Debug/lp/72/jl/classes.jar
          obj/Debug/lp/88/jl/classes.jar
          obj/Debug/lp/91/jl/classes.jar
          obj/Debug/lp/65/jl/classes.jar
          obj/Debug/lp/62/jl/classes.jar
          obj/Debug/lp/63/jl/classes.jar
          obj/Debug/lp/64/jl/classes.jar
          obj/Debug/lp/90/jl/classes.jar
          obj/Debug/lp/79/jl/classes.jar
          obj/Debug/lp/83/jl/classes.jar
          obj/Debug/lp/77/jl/classes.jar
          obj/Debug/lp/70/jl/classes.jar
          obj/Debug/lp/84/jl/classes.jar
          obj/Debug/lp/85/jl/classes.jar
          obj/Debug/lp/71/jl/classes.jar
          obj/Debug/lp/76/jl/classes.jar
          obj/Debug/lp/82/jl/classes.jar
          obj/Debug/lp/78/jl/classes.jar
          obj/Debug/lp/50/jl/bin/classes.jar
          obj/Debug/lp/51/jl/bin/classes.jar
          obj/Debug/lp/54/jl/bin/classes.jar
          obj/Debug/lp/53/jl/bin/classes.jar
          obj/Debug/lp/52/jl/bin/classes.jar
          obj/Debug/lp/55/jl/bin/classes.jar
          obj/Debug/lp/48/jl/bin/classes.jar
          obj/Debug/lp/49/jl/bin/classes.jar (TaskId:489)
  Task Parameter:DoNotPackageJavaLibraries=com.symbol.emdk.jar (TaskId:489)
  Task Parameter:EnableInstantRun=True (TaskId:489)
    JavaLibrariesToCompile: (TaskId:489)
      /Users/dean/.nuget/packages/xamarin.androidx.annotation/1.1.0/buildTransitive/monoandroid90/../../jar/androidx.annotation.annotation.jar (TaskId:489)
      /Users/dean/.nuget/packages/xamarin.androidx.collection/1.1.0/buildTransitive/monoandroid90/../../jar/androidx.collection.collection.jar (TaskId:489)
      /Users/dean/.nuget/packages/xamarin.androidx.lifecycle.common/2.2.0/buildTransitive/monoandroid90/../../jar/androidx.lifecycle.lifecycle-common.jar (TaskId:489)
      /Users/dean/.nuget/packages/xamarin.androidx.arch.core.common/2.1.0/buildTransitive/monoandroid90/../../jar/androidx.arch.core.core-common.jar (TaskId:489)
      obj/Debug/androidx/jl/2bbedeb9-4617-4e4e-b1d3-8d60e634827a.jar (TaskId:489)
      obj/Debug/lp/61/jl/classes.jar (TaskId:489)
      obj/Debug/lp/59/jl/classes.jar (TaskId:489)
      obj/Debug/lp/92/jl/classes.jar (TaskId:489)
      obj/Debug/lp/66/jl/classes.jar (TaskId:489)
      obj/Debug/lp/68/jl/classes.jar (TaskId:489)
      obj/Debug/lp/57/jl/classes.jar (TaskId:489)
      obj/Debug/lp/69/jl/classes.jar (TaskId:489)
      obj/Debug/lp/58/jl/classes.jar (TaskId:489)
      obj/Debug/lp/67/jl/classes.jar (TaskId:489)
      obj/Debug/lp/93/jl/classes.jar (TaskId:489)
      obj/Debug/lp/94/jl/classes.jar (TaskId:489)
      obj/Debug/lp/60/jl/classes.jar (TaskId:489)
      obj/Debug/lp/0/jl/formsviewgroup.jar (TaskId:489)
      obj/Debug/lp/89/jl/classes.jar (TaskId:489)
      obj/Debug/lp/73/jl/classes.jar (TaskId:489)
      obj/Debug/lp/87/jl/classes.jar (TaskId:489)
      obj/Debug/lp/80/jl/classes.jar (TaskId:489)
      obj/Debug/lp/74/jl/classes.jar (TaskId:489)
      obj/Debug/lp/75/jl/classes.jar (TaskId:489)
      obj/Debug/lp/81/jl/classes.jar (TaskId:489)
      obj/Debug/lp/86/jl/classes.jar (TaskId:489)
      obj/Debug/lp/72/jl/classes.jar (TaskId:489)
      obj/Debug/lp/88/jl/classes.jar (TaskId:489)
      obj/Debug/lp/65/jl/classes.jar (TaskId:489)
      obj/Debug/lp/62/jl/classes.jar (TaskId:489)
      obj/Debug/lp/63/jl/classes.jar (TaskId:489)
      obj/Debug/lp/64/jl/classes.jar (TaskId:489)
      obj/Debug/lp/90/jl/classes.jar (TaskId:489)
      obj/Debug/lp/79/jl/classes.jar (TaskId:489)
      obj/Debug/lp/83/jl/classes.jar (TaskId:489)
      obj/Debug/lp/77/jl/classes.jar (TaskId:489)
      obj/Debug/lp/70/jl/classes.jar (TaskId:489)
      obj/Debug/lp/84/jl/classes.jar (TaskId:489)
      obj/Debug/lp/85/jl/classes.jar (TaskId:489)
      obj/Debug/lp/71/jl/classes.jar (TaskId:489)
      obj/Debug/lp/76/jl/classes.jar (TaskId:489)
      obj/Debug/lp/82/jl/classes.jar (TaskId:489)
      obj/Debug/lp/78/jl/classes.jar (TaskId:489)
      obj/Debug/lp/50/jl/bin/classes.jar (TaskId:489)
      obj/Debug/lp/51/jl/bin/classes.jar (TaskId:489)
      obj/Debug/lp/54/jl/bin/classes.jar (TaskId:489)
      obj/Debug/lp/53/jl/bin/classes.jar (TaskId:489)
      obj/Debug/lp/52/jl/bin/classes.jar (TaskId:489)
      obj/Debug/lp/55/jl/bin/classes.jar (TaskId:489)
      obj/Debug/lp/48/jl/bin/classes.jar (TaskId:489)
      obj/Debug/lp/49/jl/bin/classes.jar (TaskId:489)
    ReferenceJavaLibraries: (TaskId:489)
      obj/Debug/lp/1/jl/com.symbol.emdk.jar (TaskId:489)
  Output Item(s): 
      _JavaLibrariesToCompile=
          /Users/dean/.nuget/packages/xamarin.androidx.annotation/1.1.0/buildTransitive/monoandroid90/../../jar/androidx.annotation.annotation.jar
                  AndroidXSkipAndroidXMigration=true
          /Users/dean/.nuget/packages/xamarin.androidx.collection/1.1.0/buildTransitive/monoandroid90/../../jar/androidx.collection.collection.jar
                  AndroidXSkipAndroidXMigration=true
          /Users/dean/.nuget/packages/xamarin.androidx.lifecycle.common/2.2.0/buildTransitive/monoandroid90/../../jar/androidx.lifecycle.lifecycle-common.jar
                  AndroidXSkipAndroidXMigration=true
          /Users/dean/.nuget/packages/xamarin.androidx.arch.core.common/2.1.0/buildTransitive/monoandroid90/../../jar/androidx.arch.core.core-common.jar
                  AndroidXSkipAndroidXMigration=true
          obj/Debug/androidx/jl/2bbedeb9-4617-4e4e-b1d3-8d60e634827a.jar
          obj/Debug/lp/61/jl/classes.jar
          obj/Debug/lp/59/jl/classes.jar
          obj/Debug/lp/92/jl/classes.jar
          obj/Debug/lp/66/jl/classes.jar
          obj/Debug/lp/68/jl/classes.jar
          obj/Debug/lp/57/jl/classes.jar
          obj/Debug/lp/69/jl/classes.jar
          obj/Debug/lp/58/jl/classes.jar
          obj/Debug/lp/67/jl/classes.jar
          obj/Debug/lp/93/jl/classes.jar
          obj/Debug/lp/94/jl/classes.jar
          obj/Debug/lp/60/jl/classes.jar
          obj/Debug/lp/0/jl/formsviewgroup.jar
          obj/Debug/lp/89/jl/classes.jar
          obj/Debug/lp/73/jl/classes.jar
          obj/Debug/lp/87/jl/classes.jar
          obj/Debug/lp/80/jl/classes.jar
          obj/Debug/lp/74/jl/classes.jar
          obj/Debug/lp/75/jl/classes.jar
          obj/Debug/lp/81/jl/classes.jar
          obj/Debug/lp/86/jl/classes.jar
          obj/Debug/lp/72/jl/classes.jar
          obj/Debug/lp/88/jl/classes.jar
          obj/Debug/lp/65/jl/classes.jar
          obj/Debug/lp/62/jl/classes.jar
          obj/Debug/lp/63/jl/classes.jar
          obj/Debug/lp/64/jl/classes.jar
          obj/Debug/lp/90/jl/classes.jar
          obj/Debug/lp/79/jl/classes.jar
          obj/Debug/lp/83/jl/classes.jar
          obj/Debug/lp/77/jl/classes.jar
          obj/Debug/lp/70/jl/classes.jar
          obj/Debug/lp/84/jl/classes.jar
          obj/Debug/lp/85/jl/classes.jar
          obj/Debug/lp/71/jl/classes.jar
          obj/Debug/lp/76/jl/classes.jar
          obj/Debug/lp/82/jl/classes.jar
          obj/Debug/lp/78/jl/classes.jar
          obj/Debug/lp/50/jl/bin/classes.jar
          obj/Debug/lp/51/jl/bin/classes.jar
          obj/Debug/lp/54/jl/bin/classes.jar
          obj/Debug/lp/53/jl/bin/classes.jar
          obj/Debug/lp/52/jl/bin/classes.jar
          obj/Debug/lp/55/jl/bin/classes.jar
          obj/Debug/lp/48/jl/bin/classes.jar
          obj/Debug/lp/49/jl/bin/classes.jar (TaskId:489)
  Output Item(s): _ReferenceJavaLibs=obj/Debug/lp/1/jl/com.symbol.emdk.jar (TaskId:489)
Done executing task "DetermineJavaLibrariesToCompile". (TaskId:489)

The required library is being placed in _ReferenceJavaLibs not _JavaLibrariesToCompile. It seem that _ReferenceJavaLibs is not used for the inputs to R8. Not sure if its supposed to though.

dellis1972 on 25 Mar 2020

👍1

@rkshnair

This is a total hack, but try adding this

 <Target Name="_Fixup" BeforeTargets="_CompileToDalvik">
    <ItemGroup>
      <_JavaLibrariesToCompileForApp Include="@(_ReferenceJavaLibs)" />
    </ItemGroup>
 </Target>

underneath the

<Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />

in your app csproj. It seems to work around the build issue. But sure if it will cause a problem at runtime though.

dellis1972 on 25 Mar 2020

If you have the EMDK jar file, you can put this in your app's project:

<AndroidExternalJavaLibrary Include="com.symbol.emdk.jar" />

Putting the file in an optional directory would also work as they mention here:
https://techdocs.zebra.com/emdk-for-android/3-1/guide/setupAndroidStudio/

But that might be an issue if you use CI/build servers.

jonathanpeppers on 25 Mar 2020

Hello,
One of our work colleges have started getting the same issue, and all of it began with an update to VS 2019 16.5/16.5.1, so my question is what version you are using on Mac - and if it might be the same issue. If so the underlaying issue is maybe in an update of Visual studio.

Reference to my thoughts: https://developercommunity.visualstudio.com/content/problem/960245/compilation-cant-be-completed-because-some-library.html

iXyles on 26 Mar 2020

@iXyles The reason is, from the latest VS update the R8 is enabled by default.

rkshnair on 26 Mar 2020

Cross-reference:

https://developercommunity.visualstudio.com/content/problem/963843/visual-studio-2019-xamarinforms-fails-compile.html

I have now added the AndroidExternalJavaLibrary workaround mentioned above to that item.

brendanzagaeski on 31 Mar 2020

In case they might be helpful for anyone, I'll add the slightly more verbose workaround steps that I wrote up for the Developer Community item here too.

Workaround

Add com.symbol.emdk.jar to the project, and set the Build Action to AndroidExternalJavaLibrary.

The com.symbol.emdk.jar file can be found by searching in the obj directory after the initial failed build. For example, in PowerShell:

Get-ChildItem -Recurse -Path obj -Filter com.symbol.emdk.jar

Additional background info

The ideal future fix for the R8 warnings for this specific library will be for Zebra's Symbol.XamarinEMDK NuGet package to add a custom MSBuild .targets file in the NuGet package to set up any consuming apps to use a version of the com.symbol.emdk.jar file from within the NuGet package as an item with the AndroidExternalJavaLibrary build action. That will mean consuming apps won't need to apply a workaround anymore, and it will allow the NuGet package to move away from using the [assembly: DoNotPackage] attribute, which is being deprecated starting in the Xamarin.Android 10.3 Preview (in Visual Studio 2019 version 16.6 Preview).

brendanzagaeski on 8 Apr 2020

Same problem for me, solved removing AndroidEnableMultiDex option from csproj, waiting for a real solution from Zebra

fgiacomelli on 13 May 2020

👍1

we at Zebra Techsupport are made aware of this issue with R8 warnings and EMDK Nuget package

we have approached our Engineering EMDK team around this and will post back an message here once we have their opinion.

internally we have an Engineering ticket with refernce "SPR39963"

xbr786 on 13 May 2020

👍3

@xbr786 Is there any update from Zebra regarding this issue? When we can expect a new release?

crazynitha on 27 May 2020

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