This can be easily reproduced by creating a new Android project (MonoGame 3.8.1.303, .NET6, Android 31), though I have the same issue with iOS. Add a new SpriteFont to your content (default Arial template is fine), and then try to build a release build (or enable the trimmer/linker on a debug build to actually see the error).
It will crash when attempting to load the SpriteFont with Could not find ContentTypeReader Type
I have tried to set the trim mode to SDK Only. I have tried to add a RootAssembly directive for MonoGame.Framework. Iāve also attempted it for Microsoft.Xna.Framework.Content.ContentTypeReader as I had read in another thread, but that errors out saying it cannot be found.
The only way Iāve been able to build my mobile builds is by disabling the trimmer/linker entirely.
I believe Iāve found a solution for this. After ripping into the SpriteFontās XNB, I discovered that the MG content loader uses System.Char by reflection when loading SpriteFonts. So, stop the linker from removing it. I tried a couple methods to only block the trimming of the System.Char type without luck. I would be interested if anyone else is doing this a bit cleaner. Hereās what you can do:
Create an XML file (ex: TrimmerRoots.xml) with this content:
I could not quite get this fix to work (I get the error below). However I simply set PublishTrimmed to false and that did the trick. I also had to delete the bin and obj folders before building. My build is not that much bigger with trimming disabled anyway. Thanks for your help!
XABBA7009: System.InvalidOperationException: Assembly list for ABI āarm64-v8aā has a different number of assemblies than other ABI lists (expected 27, found 26
at Xamarin.Android.Tasks.ArchAssemblyStore.Generate(String outputDirectory, List1 globalIndex, List1 blobPaths)
at Xamarin.Android.Tasks.AssemblyStoreGenerator.Generate(String outputDirectory)
at Xamarin.Android.Tasks.BuildApk.AddAssemblies(ZipArchiveEx apk, Boolean debug, Boolean compress, IDictionary2 compressedAssembliesInfo, String assemblyStoreApkName) at Xamarin.Android.Tasks.BuildApk.ExecuteWithAbi(String[] supportedAbis, String apkInputPath, String apkOutputPath, Boolean debug, Boolean compress, IDictionary2 compressedAssembliesInfo, String assemblyStoreApkName)
at Xamarin.Android.Tasks.BuildApk.RunTask()
at Microsoft.Android.Build.Tasks.AndroidTask.Execute() in /Users/runner/work/1/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/AndroidTask.cs:line 17