正如标题所说，我无法安装Facebook.Android包或更新
错误消息：程序包还原失败。回滚'MyProject.Android'的包更改。
今天早些时候我又遇到了另一个问题，我得到了“访问路径”xamarin.forms.build.tasks.dll“被拒绝了。”我甚至无法清理缓存，我不得不手动删除该文件以便能够恢复包。然后，我可以更新Xamarin.Forms，FreshMVVM，但不能更新提到的Android软件包。
我该怎么办？如何获得详细的错误报告？
另一个（基本）问题：如果我喜欢Facebook.Android包，我应该为基础项目和android项目或每个项目安装它吗？
编辑：完整错误：
Detected package version outside of dependency constraint: Xamarin.Android.Support.Animated.Vector.Drawable 23.4.0.1 requires Xamarin.Android.Support.v4 (= 23.4.0.1) but version Xamarin.Android.Support.v4 27.0.2 was resolved.
Detected package version outside of dependency constraint: Xamarin.Android.Support.v7.RecyclerView 23.4.0.1 requires Xamarin.Android.Support.v4 (= 23.4.0.1) but version Xamarin.Android.Support.v4 27.0.2 was resolved.
Detected package version outside of dependency constraint: Xamarin.Android.Support.Vector.Drawable 23.4.0.1 requires Xamarin.Android.Support.v4 (= 23.4.0.1) but version Xamarin.Android.Support.v4 27.0.2 was resolved.
Package Xamarin.Android.Support.Design 27.0.2 is not compatible with monoandroid71 (MonoAndroid,Version=v7.1). Package Xamarin.Android.Support.Design 27.0.2 supports: monoandroid81 (MonoAndroid,Version=v8.1)
Package Xamarin.Android.Support.v7.AppCompat 27.0.2 is not compatible with monoandroid71 (MonoAndroid,Version=v7.1). Package Xamarin.Android.Support.v7.AppCompat 27.0.2 supports: monoandroid81 (MonoAndroid,Version=v8.1)
Package Xamarin.Android.Support.v4 27.0.2 is not compatible with monoandroid71 (MonoAndroid,Version=v7.1). Package Xamarin.Android.Support.v4 27.0.2 supports: monoandroid81 (MonoAndroid,Version=v8.1)
Package Xamarin.Android.Support.v7.CardView 27.0.2 is not compatible with monoandroid71 (MonoAndroid,Version=v7.1). Package Xamarin.Android.Support.v7.CardView 27.0.2 supports: monoandroid81 (MonoAndroid,Version=v8.1)
Package Xamarin.Android.Support.v7.MediaRouter 27.0.2 is not compatible with monoandroid71 (MonoAndroid,Version=v7.1). Package Xamarin.Android.Support.v7.MediaRouter 27.0.2 supports: monoandroid81 (MonoAndroid,Version=v8.1)
现在我明白为什么在想要更新时会出现这些错误。但我仍然不明白为什么Facebook.Android不会安装。
Edit2：Android更新问题日志：
Version conflict detected for Xamarin.Android.Support.Compat. Reference the package directly from the project to resolve this issue.
MyProject.Android -> Xamarin.Android.Support.v7.MediaRouter 25.4.0.2 -> Xamarin.Android.Support.v7.Palette 25.4.0.2 -> Xamarin.Android.Support.Compat (= 25.4.0.2)
MyProject.Android -> Xamarin.Facebook.Android 4.26.0 -> Xamarin.Android.Support.CustomTabs 25.3.1 -> Xamarin.Android.Support.Compat (= 25.3.1).