protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.Main);
RecyclerView = FindViewById <RecyclerView>(Resource.Id.RecyclerView);
progress = FindViewById <ProgressBar>(Resource.Id.progress);
RecyclerView.SetLayoutManager(new LinearLayoutManager(this));
ViewModel = ViewModelProviders.Of(this).Get(Java.Lang.Class.FromType(typeof(ItemViewModel))) as ItemViewModel;
invoker = new Invoker(this);
invoker.AddViewModel(ViewModel, Response, Error);
ViewModel.InitObserver();
}