Using a ContextMenu with MvxRecyclerView (Xamarin, MvvmCross, Android)

ContextMenuRecyclerViewAdapter.cs

public class ContextMenuRecyclerViewAdapter : MvxRecyclerAdapter
{
	private readonly Action<int> _contextPositionSetter;

	public ContextMenuRecyclerViewAdapter(IMvxAndroidBindingContext bindingContext, Action<int> contextPositionSetter) : base(bindingContext)
	{
		_contextPositionSetter = contextPositionSetter;
	}

	public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
	{
		// the same code as in MvxRecyclerAdapter, we just supply our own ViewHolder class and set the _contextPositionSetter

		var itemBindingContext = new MvxAndroidBindingContext(parent.Context, BindingContext.LayoutInflaterHolder);

		var vh = new ContextMenuViewHolder(InflateViewForHolder(parent, viewType, itemBindingContext), itemBindingContext, _contextPositionSetter)
		{
			Click = ItemClick,
			LongClick = ItemLongClick
		};

		return vh;
	}
}

ContextMenuViewHolder.cs

public class ContextMenuViewHolder : MvxRecyclerViewHolder, View.IOnCreateContextMenuListener
{
	private readonly Action<int> _contextPositionSetter;

	public ContextMenuViewHolder(View itemView, IMvxAndroidBindingContext context, Action<int> contextPositionSetter) : base(itemView, context)
	{
		itemView.SetOnCreateContextMenuListener(this);
		_contextPositionSetter = contextPositionSetter;
	}

	public void OnCreateContextMenu(IContextMenu menu, View v, IContextMenuContextMenuInfo menuInfo)
	{
		// menuInfo is null when using it from RecyclerView, so we have to use the _contextPositionSetter

		MenuInflater inflater = new MenuInflater(v.Context);
		inflater.Inflate(Resource.Menu.my_context_menu, menu);

		_contextPositionSetter?.Invoke(AdapterPosition);
	}
}

MyFragmentView.cs

public class MyFragmentView : MvxFragment<MyFragmentViewModel>
{		
	private MvxRecyclerView _list;
	private int _contextMenuItemPosition;

	public override bool OnContextItemSelected(IMenuItem item)
	{
		// item.MenuInfo is null when using it from RecyclerView, so we have to use _contextMenuItemPosition

		var myItem = _list.Adapter.GetItem(_contextMenuItemPosition) as MyItem;
		if (myItem != null)
		{
			switch (item.ItemId)
			{
				// TODO: handle relevant menu items and "return true;"

				default:
					break;
			}
		}

		return base.OnContextItemSelected(item);
	}

	public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
	{
		base.OnCreateView(inflater, container, savedInstanceState);
		var view = this.BindingInflate(Resource.Layout.my_fragment_layout, null);

		_list = view.FindViewById<MvxRecyclerView>(Resource.Id.list);

		// this action will be invoked every time a context menu is created and supplied with the item's position that created the menu
		Action<int> contextMenuItemPositionSetter = (pos) => _contextMenuItemPosition = pos;

		// explicitly using the fragment's BindingContext, because MvxAndroidBindingContextHelpers.Current() returns null
		var adapter = new ContextMenuRecyclerViewAdapter((IMvxAndroidBindingContext)BindingContext, contextMenuItemPositionSetter);
		_list.Adapter = adapter;

		RegisterForContextMenu(_list);

		return view;
	}
}