OAuth2Authenticator - Object reference not set to an instance of an object-CodePudding

The

Moreover presenter and auth aren't null.

Stack Trace :

at Xamarin.Auth.Presenters.OAuthLoginPresenter.Login (Xamarin.Auth.Authenticator authenticator) [0x00012] in <3887a0d7d292416b83829cf88b593985>:0 at Test.ViewModels.MainPageViewModel._yOauth () [0x00078] in D:\\Test\Mobile\Test\ViewModels\MainPageViewModel.cs:107 at Test.ViewModels.MainPageViewModel.<.ctor>b__7_0 () [0x00001] in D:\MyUtilits\Test\Mobile\Test\ViewModels\MainPageViewModel.cs:29 at Xamarin.Forms.Command <>c__DisplayClass4_0.<.ctor>b__0 (System.Object o) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Command.cs:74 at Xamarin.Forms.Command.Execute (System.Object parameter) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Command.cs:112 at Xamarin.Forms.ButtonElement.ElementClicked (Xamarin.Forms.VisualElement visualElement, Xamarin.Forms.Internals.IButtonElement ButtonElementManager) [0x00008] in D:\a\1\s\Xamarin.Forms.Core\ButtonElement.cs:60 at Xamarin.Forms.Button.SendClicked () [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Button.cs:173 at Xamarin.Forms.Platform.Android.ButtonElementManager.OnClick (Xamarin.Forms.VisualElement element, Xamarin.Forms.IButtonController buttonController, Android.Views.View v) [0x00000] in D:\a\1\s\Xamarin.Forms.Platform.Android\ButtonElementManager.cs:25 at Xamarin.Forms.Platform.Android.FastRenderers.ButtonRenderer.Android.Views.View.IOnClickListener.OnClick (Android.Views.View v) [0x00000] in D:\a\1\s\Xamarin.Forms.Platform.Android\FastRenderers\ButtonRenderer.cs:72 at Android.Views.View IOnClickListenerInvoker.n_OnClick_Landroid_view_View_ (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_v) [0x00010] in /Users/builder/azdo/_work/1/s/xamarin-android/src/Mono.Android/obj/Release/monoandroid10/android-29/mcw/Android.Views.View.cs:2230 at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.43(intptr,intptr,intptr)

CodePudding user response：

I had a similar issue, and all i had to do is add this line in Android Project

global::Xamarin.Auth.Presenters.XamarinAndroid.AuthenticationConfiguration.Init(this, savedInstanceState);

so that it looks like this:

... protected override void OnCreate(Bundle savedInstanceState) { base.OnCreate(savedInstanceState); Xamarin.Essentials.Platform.Init(this, savedInstanceState); global::Xamarin.Forms.Forms.Init(this, savedInstanceState); global::Xamarin.Auth.Presenters.XamarinAndroid.AuthenticationConfiguration.Init(this, savedInstanceState); LoadApplication(new App()); } ...

Not sure, but for iOS and other platforms you might require something similar. Please refer to https://github.com/moljac/Xamarin.Auth.Samples.NugetReferences/ for some samples...