为什么在 Visual Studio 2019 (XAMARIN) 中找不到 Android 库

Question

I was working on a project a few days ago and everything was ok. I just got a new PC a couple days ago and I wanted to work on it, but for some reason all Android libraries were not found. For example:

using Android.Content;
using Android.Net;

I had both Java and Android SDK installed and in my system path env. I also noticed this weird yellow warning in my Dependencies -> Assemblies -> Mono.Android

Answer 1

I'm posting the solution because it took me two full days to figure out the solution.

If you go to yourprojectname.csproj file you can se this:

<ItemGroup>
    <Reference Include="Mono.Android">
      <HintPath>..\..\..\..\..\..\..\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\MonoAndroid\v9.0\Mono.Android.dll</HintPath>
    </Reference>
  </ItemGroup>

And this is the problem. The path to the Mono.Android.dll was never found, as my Visual Studio installation was on C:/... while my project was on D:/...

On my old laptop I only had one disk so the problem never occured. I fixed this by moving my project to the same disk that my Visual Studio installation is on (in my case to C:/... )