Migrating AndroidX packages to `<AndroidLibrary>`

[jpobst]

(I made this an issue so I can provide context and we can determine the best way forward.)

Today, the AndroidX packages for an .aar we bind operate like this:

• cake unzips the .aar into a directory
• The project templates produces bindings using <InputJar Include="$(extracted_dir)/classes.jar" /> (which will not ship the Java binary)
• The .aar is added to the NuGet package with <None>
• A .targets file is added to the NuGet package which does the following:
  • Adds the .aar to the application with <AndroidAarLibrary>

Presumably this was done to in the past to speed up user application builds instead of embedding the .aar as a resource in the .dll.

We would like to remove this "hack" and use <AndroidLibrary> and no .targets file.

However, when using <AndroidLibrary> and $(AndroidGenerateResourceDesigner)=false, we end up getting errors processing Android resources with aapt:

c:\code\AndroidX\generated\androidx.preference.preference\obj\Release\net8.0-android\lp\93\jl\res\color\abc_btn_colored
_text_material.xml(21): error APT2260: attribute alpha (aka Xamarin.AndroidX.Preference:alpha) not found. [c:\code\Andr
oidX\generated\androidx.preference.preference\androidx.preference.preference.csproj::TargetFramework=net8.0-android]

The difference is that the current .targets-based binding project never processes Android resources. The consuming application would be responsible for processing them.

Should <AndroidLibrary> be processing the Android resources in a binding project? Is there a way to opt out of the processing? Or is there another way we should be going about this?

Original package example:

[jonathanpeppers]

It seems like AndroidGenerateResourceDesigner=false might just have an issue where it runs targets it could skip with a Condition.

It is on by default, so probably not a lot of test cases turn it off:

android/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets

Line 11 in 8298b6f

<AndroidGenerateResourceDesigner Condition=" '$(AndroidGenerateResourceDesigner)' == '' ">true</AndroidGenerateResourceDesigner>

[dellis1972]

So aapt probably should not be running in that case. You might want to try setting AndroidUseDesignerAssembly to false if you do not need a design at all.

So in order for our build process to automatically pick up an .aar from a nuget it has to be in the same directory as the assembly.

<ItemGroup>
      <_AarSearchDirectory   Include="@(_ReferencePath->'%(RootDir)%(Directory)')" />
      <_AarSearchDirectory   Include="@(_ReferenceDependencyPaths->'%(RootDir)%(Directory)')" />
      <_AarDistinctDirectory Include="@(_AarSearchDirectory->Distinct())" />
      <_AarFromLibraries     Include="%(_AarDistinctDirectory.Identity)*.aar" />
    </ItemGroup>

So there is that to consider as well. You will need to re-organise your nuget package.
Note we also have an issue where AndroidSkipResourceProcessing will default to false for auto detected .aar files, so that will need to be set somehow for the libraries from google since we do not need to process them for Custom views or correct their casing.

All that said, it might be better to keep the .aar file in its own .aar folder and include the target.

[jpobst]

AndroidUseDesignerAssembly = false seems to have fixed it, the errors have gone away.

So in order for our build process to automatically pick up an .aar from a nuget it has to be in the same directory as the assembly.

Yes, by changing to <AndroidLibrary>, the .aar is automatically placed in the correct spot:

Thanks for the help!