警告：跨平台 Xamarin Blank 应用程序（Xamarin.Form 便携式）

Warning IDE0006 Error encountered while loading the project. Some project features, such as full solution analysis for the failed project and projects that depend on it, have been disabled.   HelloWorld.Droid        1   Active


    Severity    Code    Description Project File    Line    Suppression State
Warning     The "ResolveLibraryProjectImports" task failed unexpectedly.
System.IO.FileNotFoundException: Could not load assembly 'HelloWorld, Version=, Culture=neutral, PublicKeyToken='. Perhaps it doesn't exist in the Mono for Android profile?
File name: 'HelloWorld.dll'
   at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.Resolve(AssemblyNameReference reference, ReaderParameters parameters)
   at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.Resolve(String fullName, ReaderParameters parameters)
   at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.Resolve(String fullName)
   at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.GetAssembly(String fileName)
   at Xamarin.Android.Tasks.ResolveLibraryProjectImports.Extract(ICollection`1 jars, ICollection`1 resolvedResourceDirectories, ICollection`1 resolvedAssetDirectories, ICollection`1 resolvedEnvironments)
   at Xamarin.Android.Tasks.ResolveLibraryProjectImports.Execute()
   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() HelloWorld.Droid            

我也遇到了同样的问题one https://stackoverflow.com/questions/40197362/warnings-creating-cross-plaftorm-xamarin-blank-app-xamarin-form-portable-in-v。但没有解决办法。

我尝试过更新 xamarin、使用 xamarin 重新安装 Visual Studio、安装几乎所有 android sdk 和工具，但错误仍然存​​在。我什至提出了一个新的解决方案，但出现了同样的错误。

Update:

根据 dev_man 提到的问题的 awnser 的建议，我删除了除 api 23 及以上之外的所有 api。之后尝试更新他提到的 nuget 软件包，但从版本 23.0 更新到 25.1.0 。这失败了，我得到了这个错误：

     Severity   Code    Description Project File    Line    Suppression State
    ErrorCould not install package 'Xamarin.Android.Support.Design 25.1.0'. 
You are trying to install this package into a project that targets 'MonoAndroid,Version=v6.0', but the package does not contain any assembly references or content files that are compatible with that framework.
 For more information, contact the package author.

有很多问题可能导致这个问题浮出水面，遗憾的是核心问题在初始阶段似乎并不明显。 上一个问题涵盖了多种可能的原因，如果仔细阅读可能会找到解决方案。当您执行各个步骤时，您的错误可能会发生变化。点击这里 https://stackoverflow.com/questions/40935404/debug-emulator-getting-started-with-android-using-xamarin