我用MVVMCross 6.2+创建了简单的Xamarin Android应用程序，并尝试正确创建标签布局。现在我在屏幕上只得到一个（最后一个注册的标签），但在轮换（娱乐）之后，它们都是三个（应该是）。怎么了？我错过了什么？怎么解决？在此先感谢您的帮助。
using System.Collections.Generic;
using System.Threading.Tasks;
using MvvmCross.Commands;
using MvvmCross.Logging;
using MvvmCross.Navigation;
using MvvmCross.ViewModels;
namespace MvvmCrossTabs.Core.ViewModels
{
public class HomeViewModel : MvxNavigationViewModel
{
public IMvxAsyncCommand ShowInitialViewModelsCommand { get; private set; }
public HomeViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService) : base(logProvider, navigationService)
{
ShowInitialViewModelsCommand = new MvxAsyncCommand(ShowInitialViewModels);
}
private async Task ShowInitialViewModels()
{
await Task.WhenAll(new List<Task>
{
NavigationService.Navigate<Tab1ViewModel>(),
NavigationService.Navigate<Tab2ViewModel>(),
NavigationService.Navigate<Tab3ViewModel>()
});
}
}
}
using MvvmCross.Logging;
using MvvmCross.Navigation;
using MvvmCross.ViewModels;
namespace MvvmCrossTabs.Core.ViewModels
{
public class Tab1ViewModel : MvxNavigationViewModel
{
public Tab1ViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService) : base(logProvider, navigationService)
{
}
}
}
using MvvmCross.IoC;
using MvvmCross.ViewModels;
using MvvmCrossTabs.Core.ViewModels;
namespace MvvmCrossTabs.Core
{
public class App : MvxApplication
{
public override void Initialize()
{
CreatableTypes()
.EndingWith("Service")
.AsInterfaces()
.RegisterAsLazySingleton();
RegisterAppStart<HomeViewModel>();
}
}
}
using System;
using Android.App;
using Android.Runtime;
using MvvmCross.Droid.Support.V7.AppCompat;
using MvvmCrossTabs.Core;
namespace MvvmCrossTabs.Android
{
[Application]
public class MainApplication : MvxAppCompatApplication<MvxAppCompatSetup<App>, App>
{
public MainApplication() : base() { }
public MainApplication(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer) { }
}
}
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/maincontent"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlways" />
<android.support.design.widget.TabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="enterAlways"
app:tabGravity="fill"
app:tabMaxWidth="0dp" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
<?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:layout_width="match_parent"
android:layout_height="match_parent">
</LinearLayout>
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat">
<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
</resources>
using Android.App;
using Android.Content.PM;
using Android.OS;
using Android.Support.V7.Widget;
using MvvmCross.Droid.Support.V7.AppCompat;
using MvvmCross.Platforms.Android.Presenters.Attributes;
using MvvmCrossTabs.Core.ViewModels;
namespace MvvmCrossTabs.Android
{
[Activity(Label = "@string/app_name", LaunchMode = LaunchMode.SingleTask, Theme = "@style/AppTheme", MainLauncher = true)]
[MvxActivityPresentation]
public class HomeView : MvxAppCompatActivity<HomeViewModel>
{
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.home);
// Replaces Action Bar with new Toolbar.
var toolbar = FindViewById<Toolbar>(Resource.Id.toolbar);
SetSupportActionBar(toolbar);
ViewModel.ShowInitialViewModelsCommand.Execute();
}
}
}
using Android.OS;
using Android.Runtime;
using Android.Views;
using MvvmCross.Droid.Support.V4;
using MvvmCross.Platforms.Android.Binding.BindingContext;
using MvvmCross.Platforms.Android.Presenters.Attributes;
using MvvmCrossTabs.Core.ViewModels;
namespace MvvmCrossTabs.Android.Views
{
[MvxTabLayoutPresentation(TabLayoutResourceId = Resource.Id.tabs, ViewPagerResourceId = Resource.Id.viewpager, Title = "Tab 1", ActivityHostViewModelType = typeof(HomeViewModel))]
[Register(nameof(Tab1View))]
public class Tab1View : MvxFragment<Tab1ViewModel>
{
public override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Create your fragment here
}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
base.OnCreateView(inflater, container, savedInstanceState);
return this.BindingInflate(Resource.Layout.tab1, null);
}
}
}
对于任何寻找此问题解决方案的人来说，目前它归结为具有实现MvxSplashScreenAppCompatActivity类的启动画面活动。
Softlion正致力于PR，这将取消这一要求。
您可以在此处跟踪问题的当前状态：Tabs with MVVMCross 6.2+
最好的解决方法是在HomeView中使用这段代码：
protected override void OnCreate(Bundle bundle)
{
var setupSingleton = MvxAndroidSetupSingleton.EnsureSingletonAvailable(this);
setupSingleton.EnsureInitialized();
base.OnCreate(bundle);
// my code here
}
谢谢@kmiterror的提示。