请告诉我路径您试图编译该项目？

Windows有对路径名的限制，所以尽你的项目转移到更短的路径命名。例如，如果您使用的是C的默认项目路径：\Users\YourUserName\Documents\VisualStudio2015\Projects\something那么也许它复制到C：\Dev

Currently banging my head against a wall with this issue, the error is preventing me from building and running my application. It is a PCL project.

   Error The "GenerateJavaStubs" task failed unexpectedly.
   System.IO.PathTooLongException: The specified path, file name, or both are  too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters.
   at System.IO.PathHelper.GetFullPathName()
   at System.IO.Path.NormalizePath(String path, Boolean fullCheck, Int32 maxPathLength, Boolean expandShortPaths)
   at System.IO.Path.GetFullPathInternal(String path)
   at System.IO.Path.GetFullPath(String path)
   at Xamarin.Android.Tasks.GenerateJavaStubs.Run()
   at Xamarin.Android.Tasks.GenerateJavaStubs.Execute()
   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() ConstructionMobileApp.Droid C:\Program Files (x86)\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets   1574    

My assembly info in the PCL:

using System.Resources;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

[assembly: AssemblyTitle("ConstructionMobileApp")]
[assembly: AssemblyDescription("")]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyCompany("")]
[assembly: AssemblyProduct("ConstructionMobileApp")]
[assembly: AssemblyCopyright("Copyright ©  2014")]
[assembly: AssemblyTrademark("")]
[assembly: AssemblyCulture("")]
[assembly: NeutralResourcesLanguage("en")]

[assembly: AssemblyVersion("1.0.0.0")]
[assembly: AssemblyFileVersion("1.0.0.0")]

Android Assembly Info:

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using Android.App;


[assembly: AssemblyTitle("ConstructionMobileApp.Droid")]
[assembly: AssemblyDescription("")]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyCompany("")]
[assembly: AssemblyProduct("ConstructionMobileApp.Droid")]
[assembly: AssemblyCopyright("Copyright ©  2014")]
[assembly: AssemblyTrademark("")]
[assembly: AssemblyCulture("")]
[assembly: ComVisible(false)]

[assembly: AssemblyVersion("1.0.0.0")]
[assembly: AssemblyFileVersion("1.0.0.0")]

[assembly: UsesPermission(Android.Manifest.Permission.Internet)]
[assembly: UsesPermission(Android.Manifest.Permission.WriteExternalStorage)]

Whats the path to the project you are trying to compile?

Windows has a limit on path names so try moving your project to a shorter named path. For example if you are using the default project path of C:\Users\YourUserName\Documents\VisualStudio2015\Projects\something then maybe copy it to c:\Dev.