MvvmCross 5.4 Android Fragments：ViewModelにナビゲートできません

Question

MainViewModelからAccountsViewModelに移動しようとしています。アプリケーションが起動すると、MainViewModelにスタックされます。私はかなりのデバッグを行い、複数の例を調べましたが、この問題を解決することはできません。関連するクラスは下記の通りです。何か他のものが必要な場合は教えてください。

のApp

using DebtBuddy.Core.ViewModels; 
using MvvmCross.Core.ViewModels; 
using MvvmCross.Platform.IoC; 

namespace DebtBuddy.Core 
{ 
    public class App : MvxApplication 
    { 
     public override void Initialize() 
     { 
      CreatableTypes() 
       .EndingWith("Service") 
       .AsInterfaces() 
       .RegisterAsLazySingleton(); 

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

      RegisterNavigationServiceAppStart<MainViewModel>(); 
     } 
    } 
} 

セットアップ

using Android.Content; 
using MvvmCross.Core.ViewModels; 
using MvvmCross.Platform.Platform; 
using MvvmCross.Droid.Views; 
using MvvmCross.Droid.Support.V7.AppCompat; 
using DebtBuddy.Core.Repositories; 
using MvvmCross.Platform; 

namespace DebtBuddy.Droid 
{ 
    public class Setup : MvxAppCompatSetup 
    { 
     public Setup(Context applicationContext) : base(applicationContext) 
     { 
     } 

     protected override IMvxApplication CreateApp() 
     { 
      var dbConn = FileAccessHelper.GetLocalFilePath("account.db3"); 
      Mvx.RegisterSingleton(new AccountRepository(dbConn)); 

      return new Core.App(); 
     } 

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

MainViewModel

using MvvmCross.Core.Navigation; 
using MvvmCross.Core.ViewModels; 

namespace DebtBuddy.Core.ViewModels 
{ 
    public class MainViewModel : MvxViewModel 
    { 
     private readonly IMvxNavigationService _navigationService; 

     public MainViewModel(IMvxNavigationService navigationService) 
     { 
      _navigationService = navigationService; 

      ShowAccountsViewModel = new MvxAsyncCommand(async() => await 
      _navigationService.Navigate<AccountsViewModel>()); 
     } 

     public IMvxAsyncCommand ShowAccountsViewModel { get; private set; } 
    } 
} 

MAINVIEW

using Android.App; 
using MvvmCross.Droid.Support.V7.AppCompat; 
using DebtBuddy.Core.ViewModels; 
using Android.OS; 
using MvvmCross.Droid.Views.Attributes; 

namespace DebtBuddy.Droid.Views 
{ 
    [MvxActivityPresentation] 
    [Activity(Theme = "@style/AppTheme")] 
    public class MainView : MvxAppCompatActivity<MainViewModel> 
    { 
     protected override void OnCreate(Bundle bundle) 
     { 
      base.OnCreate(bundle); 

      SetContentView(Resource.Layout.MainView); 

      ViewModel.ShowAccountsViewModel.ExecuteAsync(); 
     } 
    } 
} 

MainView.axml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:local="http://schemas.android.com/apk/res-auto" 
    android:orientation="vertical" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 
    <FrameLayout 
     android:id="@+id/content_frame" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" /> 
</LinearLayout> 

AccountsViewModel

using System.Collections.ObjectModel; 
using DebtBuddy.Core.Extensions; 
using DebtBuddy.Core.Interfaces.IDataServices; 
using DebtBuddy.Core.Models; 
using MvvmCross.Core.Navigation; 
using MvvmCross.Core.ViewModels; 

namespace DebtBuddy.Core.ViewModels 
{ 
    public class AccountsViewModel : MvxViewModel 
    { 
     private readonly IAccountDataService _accountDataService; 
     private readonly IMvxNavigationService _navigationService; 

     public AccountsViewModel(IMvxNavigationService navigationService, IAccountDataService accountDataService) 
     { 
      _navigationService = navigationService; 
      _accountDataService = accountDataService; 

      ShowCreateAccountViewModelCommand = new MvxAsyncCommand(async() => await _navigationService.Navigate<CreateAccountViewModel>()); 
      ShowAccountDetailViewModelCommand = new MvxAsyncCommand<Account (item => _navigationService.Navigate<AccountDetailViewModel, Account>(item)); 
     } 

     public IMvxAsyncCommand ShowCreateAccountViewModelCommand { get; private set; } 

     public IMvxAsyncCommand<Account> ShowAccountDetailViewModelCommand { get; private set; } 

     private ObservableCollection<Account> _accounts; 
     public ObservableCollection<Account> Accounts 
     { 
      get => _accounts; 
      set 
      { 
       _accounts = value; 
       RaisePropertyChanged(() => Accounts); 
      } 
     } 

     public override void Prepare() 
     { 
      LoadAccountsFromDatabase(); 
     } 

     private async void LoadAccountsFromDatabase() 
     { 
      Accounts = (await _accountDataService.GetAllAccounts()).ToObservableCollection(); 
     } 
    } 
} 

AccountsView

using Android.OS; 
using MvvmCross.Droid.Views.Attributes; 
using DebtBuddy.Core.ViewModels; 
using MvvmCross.Droid.Support.V4; 
using Android.Runtime; 
using Android.Views; 
using MvvmCross.Binding.Droid.BindingContext; 

namespace DebtBuddy.Droid.Views 
{ 
    [MvxFragmentPresentation(typeof(MainViewModel), Resource.Id.content_frame, true)] 
    [Register(nameof(AccountsView))] 
    public class AccountsView : MvxFragment<AccountsViewModel> 
    { 
     public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
     { 
      base.OnCreateView(inflater, container, savedInstanceState); 

      var view = this.BindingInflate(Resource.Layout.AccountsView, null); 

      return view; 
     } 
    } 
} 

AccountsView.axml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:local="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/main_frame" 
    android:orientation="vertical" 
    android:background="@color/white" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 
    <Mvx.MvxListView 
     android:id="@+id/account_list" 
     android:divider="@null" 
     android:scrollbars="vertical" 
     android:choiceMode="singleChoice" 
     android:layout_width="match_parent" 
     android:layout_height="0dp" 
     android:layout_weight="1" 
     android:layout_gravity="left|start" 
     local:MvxItemTemplate="@layout/item_account" 
     local:MvxBind="ItemsSource Accounts; ItemClick ShowAccountDetailViewModelCommand" /> 
    <Button 
     android:id="@+id/addAccountButton" 
     android:background="@color/white" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_weight="0" 
     android:text="Add Account" 
     android:textSize="17dp" 
     android:textColor="@color/black" 
     local:MvxBind="Click ShowCreateAccountViewModelCommand" /> 
</LinearLayout> 

Answer 1

あなたはMvvmCrossサンプルから1として、セットアップクラスを持っていたことがあり

重要な点はMvxAppCompatViewPresenterです。