MvvmCross App Won't Start after upgrading to version 6.0

Question

I upgraded my app to MvvmCross version 6.0. Now it get's to the splash screen and does nothing else. I can see the the Services are starting up by looking at the console. Here is my app.cs:

public class App : MvxApplication
{
    public override void Initialize()
    {
        MPS.ApplicationName = Settings.ApplicationName;
        EventLog.ApplicationName = Settings.ApplicationName;
        BlobCache.ApplicationName = Settings.ApplicationName;

        CreatableTypes()
            .EndingWith("Service")
            .AsInterfaces()
            .RegisterAsLazySingleton();

        CreatableTypes()
            .EndingWith("Singleton")
            .AsInterfaces()
            .RegisterAsSingleton();

        //RegisterAppStart(new CustomAppStart());
        //RegisterNavigationServiceAppStart<LoginViewModel>();
        RegisterAppStart<LoginViewModel>();
    }

}

It is pretty basic. I had converted to the new navigation system hence the RegisterNavigationServiceAppStart. That would no longer resolve so I went back to a straight RegisterAppStart. The splash screen comes up and then it stops. In case it matters, splashscreen.cs is as follows:

[Activity(
    Label = "@string/ApplicationName"
    , MainLauncher = true
    , Icon = "@drawable/icon"
    , Theme = "@style/Theme.Splash"
    , NoHistory = true)]
    //, ScreenOrientation = ScreenOrientation.Landscape)]
public class SplashScreen : MvxSplashScreenActivity
{
    public SplashScreen()
        : base(Resource.Layout.SplashScreen)
    {
    }
}

It's pretty vanilla, but I know things have changed along the way. My setup.cs is as follows:

public class Setup : MvxAndroidSetup
{
    //public Setup(Context applicationContext)
    //    : base(applicationContext)
    //{
    //}

    protected override IMvxApplication CreateApp()
    {
        return new App();
    }

    //protected override IMvxTrace CreateDebugTrace()
    //{
    //    return new DebugTrace();
    //}

    protected override IMvxAndroidViewPresenter CreateViewPresenter()
    {
        return new MvxAppCompatViewPresenter(AndroidViewAssemblies);
    }

    protected override void FillValueConverters(IMvxValueConverterRegistry registry)
    {
        base.FillValueConverters(registry);
        registry.AddOrOverwrite("DateToStringConverter", new DateToStringConverter());
        registry.AddOrOverwrite("FloatToStringConverter", new FloatToStringConverter());
        registry.AddOrOverwrite("DecimalToStringConverter", new DecimalToStringConverter());
        registry.AddOrOverwrite("BoolToViewStatesConverter", new BoolToViewStatesValueConverter());
        registry.AddOrOverwrite("ShipmentToOriginConverter", new ShipmentToOriginConverter());
        registry.AddOrOverwrite("ShipmentToDestinationConverter", new ShipmentToDestinationConverter());
        //registry.AddOrOverwrite("CustomName2", new AnotherVerySpecialValueConverter("Summer"));
    }

    protected override void FillTargetFactories(MvvmCross.Binding.Bindings.Target.Construction.IMvxTargetBindingFactoryRegistry registry)
    {
        base.FillTargetFactories(registry);
        registry.RegisterCustomBindingFactory<EditText>("FocusText",
                                                  textView => new MvxEditTextFocusBinding(textView));
        registry.RegisterCustomBindingFactory<TextView>("FocusChange",
                                                  textView => new MvxTextViewFocusChangeBinding(textView));
        //registry.RegisterCustomBindingFactory<MvxSpinner>("ItemSelected",
        //                                          spinner => new MvxSpinnerItemSelectedBinding(spinner));
    }

    protected override IEnumerable<Assembly> AndroidViewAssemblies => new List<Assembly>(base.AndroidViewAssemblies)
    {
        typeof(MvvmCross.Droid.Support.V7.RecyclerView.MvxRecyclerView).Assembly
    };

}

The only change I made to it was to remove the constructor. Per the documentation for version 6.0, the constructor no longer has parameters so I saw no reason to call it. Can anyone help?

** Update **

I added a MainApplication.cs as follows:

[Application]
public class MainApplication : MvxAppCompatApplication<Setup, App>
{
    public MainApplication(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
    {
    }
}

This got me past the splash screen, but hung up on the Initialize of the LoginViewModel.

* Logs *

Maybe this will help. Here are the event log entries:

2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Primary start
2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: FirstChance start
2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: PlatformServices start
2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: MvvmCross settings start
2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Singleton Cache start
2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: ViewDispatcher start
2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Bootstrap actions
2018-04-17 12:17:07 [TRACE] (MvvmCross.Logging.MvxLog) No view model type finder available - assuming we are looking for a splash screen - returning null
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: StringToTypeParser start
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: CommandHelper start
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: PluginManagerFramework start
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Create App
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: NavigationService
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Load navigation routes
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: App start
2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Application Initialize - On background thread
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: ViewModelTypeFinder start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: ViewsContainer start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Views start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: CommandCollectionBuilder start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: NavigationSerializer start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: InpcInterception start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: InpcInterception start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: LastChance start
2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Secondary end
2018-04-17 12:17:08 [TRACE] (MvvmCross.Logging.MvxLog) AppStart: Application Startup - On UI thread

I traced it a little further. It is hanging up on the Initialize() in the view model. I created a test to demonstrate:

public class FirstViewModel : MvxViewModel
{

    public FirstViewModel()
    {
        Task.Run(async () =>
        {
            var l = await ListDataSource.GetLocations();
            var m = l;
        });
    }

    public async override Task Initialize()
    {
        await base.Initialize();
        var l = await ListDataSource.GetLocations();
        var m = l;
    }

}

If I set a break point on the two var m = l, It will get to the one in the constructor but will never get to the one in the Initialize. GetLocations is:

    public async static Task<LocationList> GetLocations()
    {
        ListServiceClient client = NewClient();

        LocationList ret = null;
        bool TryCache = false;

        try
        {
            //ret = await client.GetLocationListAsync();
            ret = await Task<LocationList>.Factory.FromAsync((asyncCallback, asyncState) => client.BeginGetLocationList(asyncCallback, asyncState),
               (asyncResult) => client.EndGetLocationList(asyncResult), null);

            client.Close();
            await BlobCache.LocalMachine.InsertObject("Locations", ret, DateTimeOffset.Now.AddDays(Settings.CacheDays));
        }
        catch (TimeoutException ex)
        {
            client.Abort();
            EventLog.Error(ex.ToString());
            TryCache = true;
        }
        catch (CommunicationException ex)
        {
            client.Abort();
            EventLog.Error(ex.ToString());
            TryCache = true;
        }
        catch (Exception ex)
        {
            EventLog.Error(ex.ToString());
            TryCache = true;
        }

        if (TryCache)
        {
            try
            {
                ret = await BlobCache.LocalMachine.GetObject<LocationList>("Locations");
            }
            catch (KeyNotFoundException)
            {
                ret = null;
            }
        }

        return ret;
    }

If you set a break point on Client.Close(), it will get there if called from the constructor but not if its called from Initialize.

Answer 1

My problem was twofold. First, when you upgrade to version 6.0 using Android, you now have to include a MainApplication.cs as follows:

[Application]
public class MainApplication : MvxAppCompatApplication<Setup, App>
{
    public MainApplication(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
    {
    }
}

Without this, you will get stuck on the SplashScreen. Secondly, you need to know that the Initialize in the first ViewModel that you display has to be synchronous. As @Ale_lipa mentioned, an MvvmCross Author wrote a blog post explaining why this is and what to do about it.

https://nicksnettravels.builttoroam.com/post/2018/04/19/MvvmCross-Initialize-method-on-the-first-view-model.aspx

In a nutshell, if you are using a SplashScreen and you really need the Initialize for your first ViewModel to be Async, you can add a CustomAppStart as follows:

public class CustomMvxAppStart<TViewModel> : MvxAppStart<TViewModel>
     where TViewModel : IMvxViewModel
{
     public CustomMvxAppStart(IMvxApplication application, IMvxNavigationService navigationService) : base(application, navigationService)
     {
     }

    protected override void NavigateToFirstViewModel(object hint)
     {
         NavigationService.Navigate<TViewModel>();
     }
}

In you App.cs, replace your:

RegisterAppStart<FirstViewModel>();

with:

RegisterCustomAppStart<CustomMvxAppStart<FirstViewModel>>();

This will allow your first Initialize to be async. I am only sure it works for Android and only if you are using a SplashScreen.

Answer 2

I am quite clear, that this is not the issue related to the code from this question, but it's directly related to upgrade to MvvmCross 6.0 I've bumped into.

Just adding this as it might help someone to save a few hours as this thing not mentioned in official documentation reg. upgrading as of now.

So, in my case it was an issue with overloaded methods in Setup class:

    public override IEnumerable<Assembly> GetViewAssemblies()
    {
        var list = new List<Assembly>();
        list.AddRange(base.GetViewAssemblies());
        list.Add(typeof(App).GetTypeInfo().Assembly);

        return list;
    }

    public override IEnumerable<Assembly> GetViewModelAssemblies()
    {
        var list = new List<Assembly>();
        list.AddRange(base.GetViewModelAssemblies());
        list.Add(typeof(CoreApp).GetTypeInfo().Assembly);

        return list;
    }

I needed that as my Views and ViewModel are located in separate projects. After the upgrade the app wasn't running further than initialization, without any errors. After removing those everything started working fine. (Apparently, the newest version handles that automatically).