xamarin.android – 升级到6.0版后,MvvmCross App无法启动

概述我将我的应用程序升级到MvvmCross 6.0版.现在它可以进入启动画面并且不做任何其他事情.通过查看控制台,我可以看到服务正在启动.这是我的app.cs： public class App : MvxApplication{ public override void Initialize() { MPS.ApplicationName = Settings.A 我将我的应用程序升级到MvvmCross 6.0版.现在它可以进入启动画面并且不做任何其他事情.通过查看控制台,我可以看到服务正在启动.这是我的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>();    }}

这是非常基本的.我已经转换为新的导航系统因此RegisterNavigationServiceAppStart.那将不再解决,所以我回到了直接的RegisterappStart.启动画面出现然后停止.如果重要,splashscreen.cs如下：

[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)    {    }}

这很香草,但我知道事情已经发生了变化.我的setup.cs如下：

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    };}

我对它做的唯一改变是删除构造函数.根据6.0版的文档,构造函数不再有参数,所以我没有理由调用它.有人可以帮忙吗？

**更新**

我添加了一个MainApplication.cs,如下所示：

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

这让我超越了启动画面,但挂起了Loginviewmodel的Initialize.

*日志*

也许这会有所帮助.以下是事件日志条目：

2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Primary start2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: FirstChance start2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: PlatformServices start2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: MvvmCross settings start2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Singleton Cache start2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: VIEwdispatcher start2018-04-17 12:17:06 [TRACE] (MvvmCross.Core.MvxSetup) Setup: bootstrap actions2018-04-17 12:17:07 [TRACE] (MvvmCross.Logging.MvxLog) No vIEw model type finder available - assuming we are looking for a splash screen - returning null2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: StringToTypeParser start2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: CommandHelper start2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: PluginManagerFramework start2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Create App2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: NavigationService2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Load navigation routes2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: App start2018-04-17 12:17:07 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Application Initialize - On background thread2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: viewmodelTypeFinder start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: VIEwsContainer start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: VIEws start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: CommandCollectionBuilder start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: NavigationSerializer start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: InpcInterception start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: InpcInterception start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: LastChance start2018-04-17 12:17:08 [TRACE] (MvvmCross.Core.MvxSetup) Setup: Secondary end2018-04-17 12:17:08 [TRACE] (MvvmCross.Logging.MvxLog) AppStart: Application Startup - On UI thread

我进一步追踪它.它挂在视图模型中的Initialize()上.我创建了一个测试来演示：

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;    }}

如果我在两个var m = l上设置一个断点,它将到达构造函数中的断点,但永远不会到达Initialize中的断点. GetLocations是：

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;    }

如果在ClIEnt.Close()上设置一个断点,如果从构造函数调用它,它将到达那里,但如果从Initialize调用则不会.

解决方法 我的问题是双重的.首先,当您使用AndroID升级到6.0版时,您现在必须包含MainApplication.cs,如下所示：

[Application]public class MainApplication : MvxAppCompatApplication<Setup,transfer)    {    }}

如果没有这个,你将被困在SplashScreen上.其次,您需要知道您显示的第一个viewmodel中的Initialize必须是同步的.正如@Ale_lipa所提到的,一位MvvmCross作者撰写了一篇博客文章,解释了为什么会这样做以及如何处理它.

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

简而言之,如果您使用的是SplashScreen,并且您确实需要将第一个viewmodel的Initialize作为Async,则可以按如下方式添加CustomAppStart：

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>();     }}

在你的App.cs中,替换你的：

RegisterappStart<Firstviewmodel>();

有：

RegisterCustomAppStart<CustomMvxAppStart<Firstviewmodel>>();

这将允许您的第一个Initialize异步.我只确定它适用于AndroID,并且只有在使用SplashScreen时才有效.

总结

以上是内存溢出为你收集整理的xamarin.android – 升级到6.0版后,MvvmCross App无法启动全部内容，希望文章能够帮你解决xamarin.android – 升级到6.0版后,MvvmCross App无法启动所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。