Android Binding Library project library reference error, Mono.Android, Version=0.0.0.0

Question

I have a cross platform project created on VS2017(15.9.22) community and later on moved to VS2019(16.5.4) Community . I am trying to implement an Indian payment gateway, called RazorPay. It supports native android sdk , so they provide aar files. And I am using that aar file via Binding Library.

Initially I started my project in 2017 Community but later on switched to 2019 edition hoping it will a more stable version with latest support for Xamarin android and its SDK. Anyways, My Project has a .Net Standard Project with Android Project as well. .net Standard was 2.0, which after upgrading , I changed to 2.1 as I was getting a mismatch error.

Later on , in VS2019 , I created a new Binding Library project and build that rar file using BuildAction = LibraryProjectZip. As with other options it was not usable. Not able to use it in code. Also I need to add these two lines in order to make build successful.

<remove-node path="/api/package[@name='com.razorpay']/interface[@name='PaymentResultListener']" />
 <add-node path="/api/package[@name='com.razorpay']/interface[@name='PaymentResultWithDataListener']" />

After adding it to both the projects (standard& android), I am calling this dll in one of the xaml file of Standard Project. But now I am getting errors. I am attaching all required screenshots here. Please help me out. I am fairly new developer with Xamarin and Cross Platform environment. Following are the screenshots of settings

1. Error

2. Android Project

3. Binder Project

4. .Net Standard Project

   

Answer 1

It was fixed by adding/updating required project reference from Nuget package manager. Also removing bin/obj and rebuilding of both the projects did the trick.