我是 Xamarin android 開發的新手。我從 git 中提取代碼。之后，我在 Visual Studio 中打開了我的解決方案。我清理了解決方案 - 現在很好。然后我嘗試構建它顯示錯誤的解決方案。>Restoring NuGet packages...To prevent NuGet from restoring packages during build, open the Visual Studio Options dialog, click on the Package Manager node and uncheck 'Allow NuGet to download missing packages during build.'NuGet Package restore failed for project app: Unable to find version '2.0.0' of package 'FastAndroidCamera'.  C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\: Package 'FastAndroidCamera.2.0.0' is not found on source 'C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\'.  https://api.nuget.org/v3/index.json: Unable to load the service index for source https://api.nuget.org/v3/index.json.  An error occurred while sending the request.  The remote name could not be resolved: 'api.nuget.org'1>------ Rebuild All started: Project: app, Configuration: Debug Any CPU ------1>D:\PRANAV\TOLL\GIT\MobileApp-12-06-2018\MobileApp\app\app.csproj(467,5): error : This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is ..\packages\Xamarin.Build.Download.0.4.3\build\Xamarin.Build.Download.props.========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========\這是我得到的錯誤。所以伙計們你能弄清楚我在哪里做錯了嗎？