How to read linker error in Xamarin - xamarin

Question

I get the following error while executing my Xamarin Android app in release mode. I suppose something is missing in LinkerPleaseInclude.cs, but the error message is not very helpful.
09-25 16:17:38.140 W/art ( 1082): JNI RegisterNativeMethods: attempt to register 0 native methods for mvvmcross.binding.droid.views.MvxRadioGroup
[0:] MvxBind:Error: 2,89 Exception thrown during the view binding ArgumentNullException: missing source event info in MvxWeakEventSubscription
Parameter name: sourceEventInfo
at MvvmCross.Platform.WeakSubscription.MvxWeakEventSubscription`2[TSource,TEventArgs]..ctor (Android.Widget.TextView source, System.Reflection.EventInfo sourceEventInfo, System.EventHandler`1[TEventArgs] targetEventHandler) [0x00017] in <54d9eb77c4d448d4bc5e7c7a5cdd0a97>:0
at MvvmCross.Platform.WeakSubscription.MvxWeakEventSubscription`2[TSource,TEventArgs]..ctor (Android.Widget.TextView source, System.String sourceEventName, System.EventHandler`1[TEventArgs] targetEventHandler) [0x00012] in <54d9eb77c4d448d4bc5e7c7a5cdd0a97>:0
at MvvmCross.Platform.WeakSubscription.MvxWeakSubscriptionExtensionMethods.WeakSubscribe[TSource,TEventArgs] (TSource source, System.String eventName, System.EventHandler`1[TEventArgs] eventHandler) [0x00000] in <54d9eb77c4d448d4bc5e7c7a5cdd0a97>:0
at MvvmCross.Binding.Droid.Target.MvxTextViewTextTargetBinding.SubscribeToEvents () [0x0000b] in <cc9453c0f5794d529a8b1975bb62dd40>:0
at MvvmCross.Binding.Bindings.MvxFullBinding.CreateTargetBinding (System.Object target) [0x00057] in <5d9349f2d9c240e38eaeca40fe71d977>:0
at MvvmCross.Binding.Bindings.MvxFullBinding..ctor (MvvmCross.Binding.MvxBindingRequest bindingRequest) [0x0002f] in <5d9349f2d9c240e38eaeca40fe71d977>:0
at MvvmCross.Binding.Binders.MvxFromTextBinder.BindSingle (MvvmCross.Binding.MvxBindingRequest bindingRequest) [0x00000] in <5d9349f2d9c240e38eaeca40fe71d977>:0
at MvvmCross.Binding.Binders.MvxFromTextBinder+<>c__DisplayClass2_0.<Bind>b__0 (MvvmCross.Binding.Bindings.MvxBindingDescription description) [0x00018] in <5d9349f2d9c240e38eaeca40fe71d977>:0
at System.Linq.Utilities+<>c__DisplayClass2_0`3[TSource,TMiddle,TResult].<CombineSelectors>b__0 (TSource x) [0x00012] in <9ecdeee51aa740839577d6db9550e95f>:0
at System.Linq.Utilities+<>c__DisplayClass2_0`3[TSource,TMiddle,TResult].<CombineSelectors>b__0 (TSource x) [0x00000] in <9ecdeee51aa740839577d6db9550e95f>:0
at (wrapper delegate-invoke) System.Func`2[System.Collections.Generic.KeyValuePair`2[System.String,MvvmCross.Binding.Parse.Binding.MvxSerializableBindingDescription],System.Collections.Generic.KeyValuePair`2[System.Object,MvvmCross.Binding.Bindings.IMvxUpdateableBinding]]:invoke_TResult_T (System.Collections.Generic.KeyValuePair`2<string, MvvmCross.Binding.Parse.Binding.MvxSerializableBindingDescription>)
at System.Linq.Enumerable+SelectEnumerableIterator`2[TSource,TResult].MoveNext () [0x00048] in <9ecdeee51aa740839577d6db9550e95f>:0
at System.Collections.Generic.List`1[T].InsertRange (System.Int32 index, System.Collections.Generic.IEnumerable`1[T] collection) [0x000ea] in <b2855d13f99e445b95990a59348d98e8>:0
at System.Collections.Generic.List`1[T].AddRange (System.Collections.Generic.IEnumerable`1[T] collection) [0x00000] in <b2855d13f99e445b95990a59348d98e8>:0
at MvvmCross.Binding.Droid.Binders.MvxAndroidViewBinder.StoreBindings (Android.Views.View view, System.Collections.Generic.IEnumerable`1[T] newBindings) [0x00028] in <cc9453c0f5794d529a8b1975bb62dd40>:0
at MvvmCross.Binding.Droid.Binders.MvxAndroidViewBinder.ApplyBindingsFromAttribute (Android.Views.View view, Android.Content.Res.TypedArray typedArray, System.Int32 attributeId) [0x0001c] in <cc9453c0f5794d529a8b1975bb62dd40>:0
I see, something is missing with MvxRadioGroup. How do I find out what to add in LinkerPleaseInclude?
My binding for MvxRadioGroup is the following:
<MvxRadioGroup
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_marginTop="6dp"
local:MvxBind="ItemsSource GenderAnswers; SelectedItem GenderAnswer"
local:MvxItemTemplate="#layout/radioitem_enum" />
and my LinkerPleaseInclude is still empty.
Here's the defintiion of the properties in view model:
public IEnumerable<GenderQuestionAnswers> GenderAnswers => Enum.GetValues(typeof(GenderQuestionAnswers)).Cast<GenderQuestionAnswers>();
public GenderQuestionAnswers? GenderAnswer
{
get => _genderAnswer;
set => SetProperty(ref _genderAnswer, value);
}
[edit 2017-09-27]: added code for MvxRadioGroup binding
[edit 2017-09-27]: added snippet for properties in view model

Answer 1

I ended up adding theses lines to LinkerPleaseInclude in addition to the file mentioned by #york-shen-msft
public void Include(RadioButton radioButton)
{
radioButton.CheckedChange += (sender, args) => radioButton.Checked = args.IsChecked
}
Well, that doesn't really answer my question as I wanted to know how to find the correct solution without searching the whole internet for lines others included before and do trial and error, but it solves my actual problem for the moment.