在Xamarin.Forms中使用Android支持库API Level 26（MonoAndroid 8.0 Oreo）？

Question

I can't upgrade Android support libraries to 26.xx (API level 26 = 8.0 Oreo) because Xamarin.forms have a strict dependency to 25.xx It seems Xamarin.Forms don't support Mono.Android 8.0?

Example: When trying to upgrade Xamarin.Android.Support.Design to 26.1.0.1 the following error occurs: "Version conflict detected for Xamarin.Android.Support.Compat. Reference the package directly from the project to resolve this issue. TestApp.Android -> Xamarin.Android.Support.Design 26.1.0.1 -> Xamarin.Android.Support.Compat (= 26.1.0.1) TestApp.Android -> Xamarin.Android.Support.v4 25.4.0.2 -> Xamarin.Android.Support.Compat (= 25.4.0.2)."

And also, if you look at the dependencies for the Xamarin.Forms nuget package, MonoAndroid 8.0 isn't even listed. Why is that? And what can I do to use API level 26 support libraries in XF?

Answer 1

You need to make sure you have the Android SDK installed for Oreo. You then need to go to the android project properties (Right click on the project folder in the solution explorer and select 'Properies' from the popup menu.

Under the 'Application Tab', you will find 'Compile using Android version: (Target Framework)' Select the Oreo SDK. Now you should be able to update the app compat libraries to use 26.2.0.1.

Answer 2

if you look at the dependencies for the Xamarin.Forms nuget package, MonoAndroid 8.0 isn't even listed. It seems Xamarin.Forms don't support Mono.Android 8.0?

You could use Mono.Android 8.0 with Xamarin.Forms . Here are my nuget packages .

Version conflict detected for Xamarin.Android.Support.Compat. Reference the package directly from the project to resolve this issue. TestApp.Android -> Xamarin.Android.Support.Design 26.1.0.1 -> Xamarin.Android.Support.Compat (= 26.1.0.1) TestApp.Android -> Xamarin.Android.Support.v4 25.4.0.2 -> Xamarin.Android.Support.Compat (= 25.4.0.2).

The Xamarin.Android.Support.Compat 26.1.0.1 NuGet package contains assemblies for MonoAndroid v8.0 . So you will need to change the target framework of your Android project to be 8.0. You should be able to change that in the Visual Studio project options .

You may need to update your Android SDKs if v8.0 is not available.

Using android support libraries API Level 26 (MonoAndroid 8.0 Oreo) in Xamarin.Forms?

• Install Android 8.0 SDK
• Adjust Target SDK version in the project settings in VS
• Upgrade your nunget package. (Include Xamarin.Forms package)

In theory, we should be done here. However, if it stil not work, you could do some additional steps:

• Remove all "bin" and "obj" folders in the solution
• Restart VS
• Do a nuget restore and rebuild

Answer 3

If you set your targeted framework lets say to 8.1 make sure that your .csproj has the folowwing <TargetFrameworkVersion>v8.1</TargetFrameworkVersion>

The problem for me was that I also had a <TargetFrameworkVersion>v7.1</TargetFrameworkVersion> that I had to delete. Once I deleted this line everything started working.

Apparently visual studio wasn't able to remove previous version from csproj.

You can access csproj by unloading the android project, then right click on android project, edit csproj, then you can look for TargetFrameworkVersion tags.