How to bind an Android Library which is build using Data Binding

[basheerkohli]

Steps to Reproduce

1. Create Android Library with data binding enabled using android studio.
2. Now try to create DLL for the android library using visual studio.
3. Build process is success. But you won't find classes relating to the Data Binding.
4. In the Build logs you will find a warning
   [ noClassDefFoundError: Landroidx/databinding/DataBinderMapperImpl ]

Expected Behavior

Actual Behavior

Version Information

Log File

[moljac]

@basheerkohli
Databinding in Android (Android.Studio) relies on gradle plugin[s] what would map to MSBuild Tasks, Targets and of course Custom Tasks. This is a lot and needs resources (analysis, design and coding-implementation)

Thus we did not bind Databinding group (and artifacts).

We redirect people to use Xamarin (XAML) databindings infrastructure. I know this is Xamarin.Android not Xamarin.Forms.

If you want we can discuss it. If you are willing to do some research (what gradle plugins do) and analysis it may turn out that effort is not too big.

But, NO PROMISES from our side

[basheerkohli]

Hard to take that from you. But again thank you for your quick response @moljac . I have generated an SDK in native with data binding enabled. What you have said is correct as data binding relies on Gradle plugin[s] & has no issues while consuming the SDK from React Native, Ionic frameworks. But unfortunately, in this case, I have to think of the alternative of replacing Data binding with old school view reference objects. Thank you for the quick response. Cheers.

[paulzotov829]

Hi Did you fix it?

[moljac]

@paulzotov829

He did not fix it. We do not support that (yet).

[4brunu]

Any news or plans on supporting DataBinding and ViewBinding?

[moljac]

No. Not at the moment.

[4brunu]

For those interested in this issue, I leave here some info, of some research and experimentations regarding binding Android Libraries that use DataBinding or ViewBinding.

To bind an Android library that uses ViewBinding is very easy.
The only thing we have to do is add the dependency androidx.databinding:viewbinding, and it just works.
I already create an issue, asking for the bind of this dependency dotnet/android-libraries#243.

To bind an Android Library that uses DataBinding it's not so easy.
I tried to add the dependencies of DataBinding, but it didn't work.

implementation 'androidx.databinding:databinding-common:4.1.2'
implementation 'androidx.databinding:databinding-runtime:4.1.2'
implementation 'androidx.databinding:databinding-adapters:4.1.2'

It requires the DataBinding gradle plugin and annotation processing to be enable on the consumer side, otherwise it throws the error [ noClassDefFoundError: Landroidx/databinding/DataBinderMapperImpl ]
So supporting DataBinding will required a lot more work and investigation.

For now I will be happy with the support for ViewBinding, since it's easy to support, google it's pushing it, it's becoming more popular and widely used.

[moljac]

WIP

dotnet/android-libraries#244

[4brunu]

I'm leaving here this extra information in case it helps anyone.
Now that https://www.nuget.org/packages/Xamarin.AndroidX.DataBinding.ViewBinding/ is already published on NuGet, I was able to bind an Android library the uses View Binding.

In the begining I was havving the following error

Error CS0738: 'ActivityTimeBinding' does not implement interface member 'IViewBinding.Root'. 
'ActivityTimeBinding.Root' cannot implement 'IViewBinding.Root' because it does not have the matching return type of 'View'. (CS0738)

The solution I used was to remove the generated ViewBinding source from the public API by putting this in Metadata.xml and it worked.

    <remove-node path="/api/package[@name='com.example.mylibrary.databinding']" /> 

@moljac thanks for your help 🙂

[jeanraymonddaher]

Thank you for sharing @4brunu , it fixed my issue !