Mvvmcross: No view model association found for candidate view MainActivity

[pablogupi]

🐛 Bug Report

Hello! I have a Xamarin Forms application with MVVMCross. I just updated to version 6.2.2. When run Android application, splash activity show correctly. Seconds after, screen change color to black and appear in log this message: No view model association found for candidate view MainActivity. In version 6.2.1 works perfectly. In 6.2.2 work perfectly in iOS.

Expected behavior

After the splash should appear the first view of the app

Reproduction steps

   [Activity(Label = "test",
    MainLauncher = true,
    Icon = "@mipmap/logo",
    Theme = "@style/Theme.Splash",
    NoHistory = true,
    ScreenOrientation = ScreenOrientation.Portrait)]
public class SplashScreen
    : MvxFormsSplashScreenActivity<Setup, App, FormsApp>
{

    public SplashScreen()
      : base(Resource.Layout.SplashScreen)
    {

    }


    protected override Task RunAppStartAsync(Bundle bundle)
    {
        StartActivity(typeof(MainActivity));
        return Task.CompletedTask;
    }
}

public class Setup : MvxFormsAndroidSetup<Core.App, FormsApp>
{
    #region Methods

    protected override IMvxAndroidViewsContainer CreateViewsContainer(Context applicationContext)
    {
        var viewsContainer =
            ((FormsApp) Application.Current).LoadViewsContainer(new MvxAndroidViewsContainer(applicationContext));
        return (IMvxAndroidViewsContainer) viewsContainer;
    }

    protected override void InitializeFirstChance()
    {
        base.InitializeFirstChance();
        Core.App.LoadServiceLocator();
    }

    protected override IMvxFormsPagePresenter CreateFormsPagePresenter(IMvxFormsViewPresenter viewPresenter)
    {
        var presenter = new MvxFormsPagePresenter(viewPresenter);
        Mvx.IoCProvider.RegisterSingleton<IMvxFormsPagePresenter>(presenter);
        return presenter;
    }

    #endregion
}

 [Activity(Label = "test", Icon = "@mipmap/logo", Theme = "@style/AppTheme",
    ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation, LaunchMode = LaunchMode.SingleTop, ScreenOrientation = ScreenOrientation.Portrait)]
public class MainActivity : MvxFormsAppCompatActivity
{
    static readonly string TAG = "MainActivity";

    public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Permission[] grantResults)
    {
        Plugin.Permissions.PermissionsImplementation.Current.OnRequestPermissionsResult(requestCode, permissions, grantResults);
        base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    protected override void OnCreate(Bundle bundle)
    {
        TabLayoutResource = Resource.Layout.tabbar;
        ToolbarResource = Resource.Layout.toolbar;

        Forms.Init(this, bundle);
        UserDialogs.Init(this);
        Plugin.CurrentActivity.CrossCurrentActivity.Current.Init(this, bundle);
        var platformConfig = new PlatformConfig
        {
            BitmapDescriptorFactory = new CachingNativeBitmapDescriptorFactory()
        };
        Xamarin.FormsGoogleMaps.Init(this, bundle, platformConfig);
        Xamarin.FormsGoogleMapsBindings.Init();
        XamForms.Controls.Droid.Calendar.Init();
        Rg.Plugins.Popup.Popup.Init(this, bundle);
        Plugin.Iconize.Iconize.Init(Resource.Id.toolbar, Resource.Id.sliding_tabs);
        base.OnCreate(bundle);
        CreateNotificationChannel();




    }

Configuration

Version: 6.2.2
Xamarin Forms 3.3.0.967583

Platform:

• [ ] :iphone: iOS
• [ ] :robot: Android
• [ ] :checkered_flag: WPF
• [ ] :earth_americas: UWP
• [ ] :apple: MacOS
• [ ] :tv: tvOS
• [x] :monkey: Xamarin.Forms

[Cheesebaron]

What type is MainActivity?

[pablogupi]

@Cheesebaron > What type is MainActivity?

MvxFormsAppCompatActivity. I edit first message to add MainActivity code.

[mkshiblu]

I have the same warning (No view model association found for candidate view MainActivity) on Mvx 6.2.2 and XF 3.4. @pablogupi why did you close the issue? how was it solved?

I have exactly the same setup as @pablogupi.

[diaconori]

What was the solution to this issue?

[CmdrBeavis]

Given that I'm having a very similar problem, I too would love to know what the fix was. :)

[Cheesebaron]

@CmdrBeavis make sure you have done the following:

• Changed TargetFramework to 9.0 before updating NuGet packages
  
  
  
  • If not change the target framework and for any project that still uses packages.config, uninstall the MvvmCross packages and install them again, or manually change target framework inside of packages.config to match 9.0
  
  
• Make sure your Activities inherit from MvxActivity or derivatives of that

There shouldn't be anything else you do if you are updating from an older version.

[CmdrBeavis]

@Cheesebaron First, thanks for the above. Now,

TargetFramework is 9.0.
None of my projects contain a packages.config (and I'm pretty sure they never did.)

And this is my MainActivity class declaration;

[Activity(
    Label = "MyMobileApp",
    Theme = "@style/MainTheme",
    MainLauncher = true, 
    ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation,
    LaunchMode = LaunchMode.SingleTask)]
public class MainActivity : MvxFormsAppCompatActivity<MvxFormsAndroidSetup<Core.App, UI.App>, Core.App, UI.App>

And yet I'm still getting (MvvmCross.Logging.MvxLog) No view model association found for candidate view MainActivity at runtime. :(

(Can I assume I should take this over to Stack Overflow?)

[Cheesebaron]

@CmdrBeavis where is your splash screen?

[CmdrBeavis]

I don't have one. And in fact, was just wondering; Do I HAVE TO have a splash screen? I mean, I have the first page of my app where people will either click a Login button, or a Register button, but I neither want nor need (as far as I know) a 'Splash Screen.' While we're on the subject, I'm also trying to figure out if I HAVE TO have a Setup class as well because I'd swear that the MvvmCross docs didn't say that I MUST have either. Perhaps I missed something?

I'm trying to use the StarWarsSample as well as the TipCalc app as examples, but I feel like neither may be as 'up-to-date' as one might hope.

[Sumishu]

I am still facing the same problem For MvvmCross 6.4.2 and Xamarin Form 4.5.0.617
How was the issue closed!