在Visual Studio 2017更新到15.8.1 / 15.8.2之后的Xamarin Android App项目构建问题

Question

在将Visual Studio 2017升级到15.8.1并使用Android SDK版本28（支持Android 9.0 P）之后，我们在构建基于Xamarin的Android App C＃项目时遇到了以下错误：

_LinkAssembliesNoShrink:
  Creating "obj\\ObRelease\MonoAndroid90\link.flag" because "AlwaysCreate" was specified.
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning : Failed to read 'D:\MyAndroidApp\obj\ObRelease\MonoAndroid90\android\assets\Mono.Android.dll' with debugging symbols. Retrying to load it without it. Error details are logged below. [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning : Mono.Cecil.Cil.SymbolsNotMatchingException: Symbols were found but are not matching the assembly [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadSymbols(ISymbolReader reader, Boolean throwIfSymbolsAreNotMaching) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleReader.ReadSymbols(ModuleDefinition module, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleReader.CreateModule(Image image, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadModule(Disposable`1 stream, String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadModule(String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.AssemblyDefinition.ReadAssembly(String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.ReadAssembly(String file) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning : Failed to read 'D:\MyAndroidApp\obj\ObRelease\MonoAndroid90\android\assets\System.dll' with debugging symbols. Retrying to load it without it. Error details are logged below. [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning : Mono.Cecil.Cil.SymbolsNotMatchingException: Symbols were found but are not matching the assembly [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadSymbols(ISymbolReader reader, Boolean throwIfSymbolsAreNotMaching) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleReader.ReadSymbols(ModuleDefinition module, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleReader.CreateModule(Image image, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadModule(Disposable`1 stream, String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadModule(String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.AssemblyDefinition.ReadAssembly(String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.ReadAssembly(String file) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning : Failed to read 'D:\MyAndroidApp\obj\ObRelease\MonoAndroid90\android\assets\System.Xml.dll' with debugging symbols. Retrying to load it without it. Error details are logged below. [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning : Mono.Cecil.Cil.SymbolsNotMatchingException: Symbols were found but are not matching the assembly [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadSymbols(ISymbolReader reader, Boolean throwIfSymbolsAreNotMaching) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleReader.ReadSymbols(ModuleDefinition module, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleReader.CreateModule(Image image, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadModule(Disposable`1 stream, String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.ModuleDefinition.ReadModule(String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Mono.Cecil.AssemblyDefinition.ReadAssembly(String fileName, ReaderParameters parameters) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): warning :    at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.ReadAssembly(String file) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018: The "GenerateJavaStubs" task failed unexpectedly. [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018: System.NullReferenceException: Object reference not set to an instance of an object. [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.<>c.<ToJniNameFromAttributes>b__42_0(CustomAttribute a) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.ToJniNameFromAttributes(TypeDefinition type) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.ToJniName[T](T type, Func`2 decl, Func`2 name, Func`2 ns, Func`2 overrideName, Func`2 shouldUpdateName) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.ToJniName(TypeDefinition type, ExportParameterKind exportKind) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.ToJniName(TypeDefinition type) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Java.Interop.Tools.JavaCallableWrappers.TypeNameMapGenerator.GetTypeMapping(Func`2 skipType, Func`2 key, Func`2 value) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Java.Interop.Tools.JavaCallableWrappers.TypeNameMapGenerator.WriteJavaToManaged(Stream output) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Xamarin.Android.Tasks.GenerateJavaStubs.UpdateWhenChanged(String path, Action`1 generator) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Xamarin.Android.Tasks.GenerateJavaStubs.WriteTypeMappings(List`1 types) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Xamarin.Android.Tasks.GenerateJavaStubs.Run(DirectoryAssemblyResolver res) [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Xamarin.Android.Tasks.GenerateJavaStubs.Execute() [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute() [D:\MyAndroidApp.csproj]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(2153,3): error MSB4018:    at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() [D:\MyAndroidApp.csproj]
Done Building Project "D:\MyAndroidApp.csproj" (default targets) -- FAILED.

任何线索或任何解决方案或任何解决方法？

更新：即使在Visual Studio 2017更新到15.8.2之后，问题仍然存在。

Answer 1

不是Xamarin Android项目的专家，但想提出一些建议：

1. 根据这个旧的bug，这可能是由于悬空引用而发生的。 因此，请检查您的引用，清理项目，手动清理输出（Release / Debug）文件夹并再次尝试构建项目。
2. 根据错误消息，错误来自此文件中的ToJniNameFromAttributes方法。 所以最好检查一下Java.interop包的引用。
3. 最后，您可以创建一个新的Xamarin Android应用程序，然后比较项目配置文件（csproj文件，卸载项目并右键单击解决方案资源管理器以编辑csproj文件），从工作和不工作项目并排查找有问题的项目配置下。

希望这个对你有帮助！

问题具体答案 ：

以下是我为解决问题而做的项目参考变更。 只需将其添加到此处，因为对于阅读答案的人来说，了解问题\\解决方案会更有帮助。

原始参考文献如下：

<Reference Include="Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
</Reference>
<Reference Include="Mono.Android.Export, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
</Reference>
<Reference Include="mscorlib">
  <Private>False</Private>
</Reference>
<Reference Include="System, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
</Reference>
<Reference Include="System.Core" />
<Reference Include="System.Xml, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
</Reference>

更改后的引用（构建通过）：

<Reference Include="Mono.Android" />
<Reference Include="Mono.Android.Export" />
<Reference Include="mscorlib" />
<Reference Include="System" />
<Reference Include="System.Core" />
<Reference Include="System.Xml" />