Xamarin Android与Xamarin.Auth的碰撞

Question

我用Xamarin.Auth登录Facebook。我为iOS和安卓创建了一个独立的渲染器。在auth.Completed中，我在自定义呈现器的PCL类中调用方法AfterLogin(UserInfo)。这做了一些额外的工作，然后调用

App.Current.MainPage = new NavigationPage(new MainPage());

看起来页面构造正确，所有方法都正确返回，直到抛出未处理的异常为止。唯一的文本是“发生了未处理的异常”。

在iOS中，一切都很好。它调用完全相同的PCL代码。

我不知道这是指什么观点。

编辑亚行的堆栈跟踪

  I/MonoDroid(11638): UNHANDLED EXCEPTION:

 I/MonoDroid(11638): Java.Lang.IllegalArgumentException: No view found for id 0x4 (unknown) for fragment FragmentContainer{436fa3e8 #0 id=0x4}

I/MonoDroid(11638):   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <d18287e1d683419a8ec3216fd78947b9>:0 

I/MonoDroid(11638):   at Java.Interop.JniEnvironment+InstanceMethods.CallBooleanMethod (Java.Interop.JniObjectReference instance, Java.Interop.JniMethodInfo method) [0x00068] in <5716a943049b49ca928a3a1c8d2386f4>:0 

I/MonoDroid(11638):   at Android.Runtime.JNIEnv.CallBooleanMethod (System.IntPtr jobject, System.IntPtr jmethod) [0x0000e] in <33e6e739ac344166b157e323586f11a1>:0 

I/MonoDroid(11638):   at Android.Support.V4.App.FragmentManagerInvoker.ExecutePendingTransactions () [0x00033] in <7e083afc7c9045f59e01d9c14931060d>:0 

I/MonoDroid(11638):   at Xamarin.Forms.Platform.Android.AppCompat.NavigationPageRenderer.Dispose (System.Boolean disposing) [0x00083] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\NavigationPageRenderer.cs:135 

I/MonoDroid(11638):   at Java.Lang.Object.Dispose () [0x00000] in <33e6e739ac344166b157e323586f11a1>:0 

I/MonoDroid(11638):   at Xamarin.Forms.Platform.Android.AppCompat.Platform.SetPage (Xamarin.Forms.Page newRoot) [0x0003f] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\Platform.cs:226 

I/MonoDroid(11638):   at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.InternalSetPage (Xamarin.Forms.Page page) [0x0001a] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:370 

I/MonoDroid(11638):   at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.AppOnPropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs args) [0x00012] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:321 

I/MonoDroid(11638):   at Xamarin.Forms.BindableObject.OnPropertyChanged (System.String propertyName) [0x0000a] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\BindableObject.cs:136 

I/MonoDroid(11638):   at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Element.cs:380 

I/MonoDroid(11638):   at Xamarin.Forms.Application.set_MainPage (Xamarin.Forms.Page value) [0x0008b] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Application.cs:90 

I/MonoDroid(11638):   at App.App.Instance_DataIsReady (System.Object sender, App.EventArguments.DataIsReadyEventArgs e) [0x0004d] in <9b95d86146df403c82b64e5a8ab6a9cf>:0 

I/MonoDroid(11638):   at (wrapper delegate-invoke) <Module>:invoke_void_object_DataIsReadyEventArgs (object,App.EventArguments.DataIsReadyEventArgs)

I/MonoDroid(11638):   at App.DataCache.OnDataIsReady (App.EventArguments.DataIsReadyStates state) [0x0001b] in <9b95d86146df403c82b64e5a8ab6a9cf>:0 

I/MonoDroid(11638):   at App.DataCache.set_PlayerWinnings (System.Collections.Generic.IEnumerable`1[T] value) [0x00012] in <9b95d86146df403c82b64e5a8ab6a9cf>:0 

I/MonoDroid(11638):   at App.DataCache+<RefreshData>d__37.MoveNext () [0x00351] in <9b95d86146df403c82b64e5a8ab6a9cf>:0 

I/MonoDroid(11638): --- End of stack trace from previous location where exception was thrown ---

Answer 1

Xamarin.Auth的哪个版本？如果从1.5.0版本开始，库本身就已经支持Xamarin.Forms，那么为什么要实现它呢？

为了获得更多的帮助，我们需要你方的更多信息(和代码).

Answer 2

事实证明，问题是MainPage被分配给两次。与八月无关。