Incompatible ButtonHandler when embedding MAUI page in .NET Android-project

Description

I’m testing out embedding MAUI pages into a new .NET 6 Android-project using this guide. When I try to embed a page that contains a Button control it crashes with the following exception: Microsoft.Maui.Platform.ToPlatformException: 'Microsoft.Maui.Handlers.ButtonHandler found for Microsoft.Maui.Controls.Button is incompatible'. This happens at the following statement:

var view = myMauiPage.ToPlatform(mauiContext);

When I test the same thing on a .NET 6 iOS-project, it works fine.

Steps to Reproduce

1. Create a File -> New “Android application” (.NET 6 template)
2. Follow the guide to enable MAUI embedding in the Android project.
3. Add a MAUI page to the project and add a Button to the page
4. Try to call .ToPlatform(context) on the new page

Version with bug

6.0 (current)

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

Android 12

Did you find any workaround?

Had to comment out the Button.

Relevant log output

No response

[gkarabin]

I’m running into this without trying to use embedding, with the same style enforcement backtrace. I’m porting a Xamarin.Forms app to MAUI, adding my code to a MAUI template app. My theme is “@style/Maui.SplashTheme”. It seems like that Theme has a Material Theme as a parent, so I’m not sure what’s going wrong: https://github.com/dotnet/maui/blob/c1439acf4dfeb0e5a6f56583d6a1860a12ff4a6f/src/Core/src/Platform/Android/Resources/values/styles.xml

The template app was functioning OK prior to me replacing the Android Application and Maui Programs with the ported code from my Forms app. Is it possible that something about my ported Forms code is incompatible with material theming?

Update - as everyone said, you really do want to set an exception catchpoint on System.Exception to get at the inner exception. Doing so points me to the culprit, in my code.

[andreas-nesheim]

Here’s the entire stack trace:

Microsoft.Maui.Platform.ToPlatformException: Microsoft.Maui.Handlers.ButtonHandler found for Microsoft.Maui.Controls.Button is incompatible —> Java.Lang.IllegalArgumentException: The style on this component requires your app theme to be Theme.MaterialComponents (or a descendant). at Java.Interop.JniEnvironment.InstanceMethods.CallNonvirtualVoidMethod(JniObjectReference instance, JniObjectReference type, JniMethodInfo method, JniArgumentValue* args) in /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniEnvironment.g.cs:line 12324 at Java.Interop.JniPeerMembers.JniInstanceMethods.FinishCreateInstance(String constructorSignature, IJavaPeerable self, JniArgumentValue* parameters) in /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceMethods.cs:line 142 at Google.Android.Material.Button.MaterialButton…ctor(Context context) in C:\a_work\1\s\generated\com.google.android.material.material\obj\Release\net6.0-android\generated\src\Google.Android.Material.Button.MaterialButton.cs:line 385 at Microsoft.Maui.Platform.MauiMaterialButton…ctor(Context context) in D:\a_work\1\s\src\Core\src\Platform\Android\MauiMaterialButton.cs:line 13 at Microsoft.Maui.Handlers.ButtonHandler.CreatePlatformView() in D:\a_work\1\s\src\Core\src\Handlers\Button\ButtonHandler.Android.cs:line 27 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.IButton, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Google.Android.Material.Button.MaterialButton, Xamarin.Google.Android.Material, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].OnCreatePlatformView() in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 72 at Microsoft.Maui.Handlers.ViewHandler.OnCreatePlatformElement() in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandler.cs:line 119 at Microsoft.Maui.Handlers.ElementHandler.CreatePlatformElement() in D:\a\_work\1\s\src\Core\src\Handlers\Element\ElementHandler.cs:line 96 at Microsoft.Maui.Handlers.ElementHandler.SetVirtualView(IElement view) in D:\a\_work\1\s\src\Core\src\Handlers\Element\ElementHandler.cs:line 52 at Microsoft.Maui.Handlers.ViewHandler.SetVirtualView(IElement element) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandler.cs:line 125 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.IButton, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Google.Android.Material.Button.MaterialButton, Xamarin.Google.Android.Material, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IView view) in D:\a_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 53 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.IButton, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Google.Android.Material.Button.MaterialButton, Xamarin.Google.Android.Material, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 56 at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 64 at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 20 at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:line 307 at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 98 --- End of managed Java.Lang.IllegalArgumentException stack trace ---java.lang.IllegalArgumentException: The style on this component requires your app theme to be Theme.MaterialComponents (or a descendant). at com.google.android.material.internal.ThemeEnforcement.checkTheme(ThemeEnforcement.java:241) at com.google.android.material.internal.ThemeEnforcement.checkMaterialTheme(ThemeEnforcement.java:215) at com.google.android.material.internal.ThemeEnforcement.checkCompatibleTheme(ThemeEnforcement.java:143) at com.google.android.material.internal.ThemeEnforcement.obtainStyledAttributes(ThemeEnforcement.java:75) at com.google.android.material.button.MaterialButton.<init>(MaterialButton.java:226) at com.google.android.material.button.MaterialButton.<init>(MaterialButton.java:217) at com.google.android.material.button.MaterialButton.<init>(MaterialButton.java:213) at crc6452ffdc5b34af3a0f.MauiMaterialButton.<init>(MauiMaterialButton.java:21) at crc648a59dcc370a6a53a.MainActivity.n_onCreate(Native Method) at crc648a59dcc370a6a53a.MainActivity.onCreate(MainActivity.java:29) at android.app.Activity.performCreate(Activity.java:8051) at android.app.Activity.performCreate(Activity.java:8031) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1329) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3608) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3792) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2210) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loopOnce(Looper.java:201) at android.os.Looper.loop(Looper.java:288) at android.app.ActivityThread.main(ActivityThread.java:7839) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003) --- End of managed Java.Lang.IllegalArgumentException stack trace ---java.lang.IllegalArgumentException: The style on this component requires your app theme to be Theme.MaterialComponents (or a descendant). at com.google.android.material.internal.ThemeEnforcement.checkTheme(ThemeEnforcement.java:241) at com.google.android.material.internal.ThemeEnforcement.checkMaterialTheme(ThemeEnforcement.java:215) at com.google.android.material.internal.ThemeEnforcement.checkCompatibleTheme(ThemeEnforcement.java:143) at com.google.android.material.internal.ThemeEnforcement.obtainStyledAttributes(ThemeEnforcement.java:75) at com.google.android.material.button.MaterialButton.<init>(MaterialButton.java:226) at com.google.android.material.button.MaterialButton.<init>(MaterialButton.java:217) at com.google.android.material.button.MaterialButton.<init>(MaterialButton.java:213) at crc6452ffdc5b34af3a0f.MauiMaterialButton.<init>(MauiMaterialButton.java:21) at crc648a59dcc370a6a53a.MainActivity.n_onCreate(Native Method) at crc648a59dcc370a6a53a.MainActivity.onCreate(MainActivity.java:29) at android.app.Activity.performCreate(Activity.java:8051) at android.app.Activity.performCreate(Activity.java:8031) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1329) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3608) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3792) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2210) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loopOnce(Looper.java:201) at android.os.Looper.loop(Looper.java:288) at android.app.ActivityThread.main(ActivityThread.java:7839) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003) --- End of inner exception stack trace --- at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 113 at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 142 at Microsoft.Maui.Handlers.LayoutHandler.SetVirtualView(IView view) in D:\a\_work\1\s\src\Core\src\Handlers\Layout\LayoutHandler.Android.cs:line 43 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.ILayout, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.LayoutViewGroup, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view) in D:\a_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 56 at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler) in D:\a_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 64 at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value) in D:\a_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 20 at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value) in D:\a_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:line 307 at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 105 at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context) in D:\a_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 142 at Microsoft.Maui.Platform.ScrollViewExtensions.UpdateContent(MauiScrollView scrollView, IView content, IMauiContext context) in D:\a_work\1\s\src\Core\src\Platform\Android\ScrollViewExtensions.cs:line 36 at Microsoft.Maui.Handlers.ScrollViewHandler.MapContent(IScrollViewHandler handler, IScrollView scrollView) in D:\a_work\1\s\src\Core\src\Handlers\ScrollView\ScrollViewHandler.Android.cs:line 71 at Microsoft.Maui.PropertyMapper2.<>c__DisplayClass5_0[[Microsoft.Maui.IScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Handlers.IScrollViewHandler, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].<Add>b__0(IElementHandler h, IElement v) in D:\a\_work\1\s\src\Core\src\PropertyMapper.cs:line 183 at Microsoft.Maui.PropertyMapper.UpdatePropertyCore(String key, IElementHandler viewHandler, IElement virtualView) in D:\a\_work\1\s\src\Core\src\PropertyMapper.cs:line 47 at Microsoft.Maui.PropertyMapper.UpdateProperties(IElementHandler viewHandler, IElement virtualView) in D:\a\_work\1\s\src\Core\src\PropertyMapper.cs:line 82 at Microsoft.Maui.Handlers.ElementHandler.SetVirtualView(IElement view) in D:\a\_work\1\s\src\Core\src\Handlers\Element\ElementHandler.cs:line 74 at Microsoft.Maui.Handlers.ViewHandler.SetVirtualView(IElement element) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandler.cs:line 125 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.IScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.MauiScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IView view) in D:\a_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 53 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.IScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.MauiScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 56 at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 64 at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 20 at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:line 307 at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 105 at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 142 at Microsoft.Maui.Handlers.ContentViewHandler.UpdateContent(IContentViewHandler handler) in D:\a\_work\1\s\src\Core\src\Handlers\ContentView\ContentViewHandler.Android.cs:line 44 at Microsoft.Maui.Handlers.ContentViewHandler.MapContent(IContentViewHandler handler, IContentView page) in D:\a\_work\1\s\src\Core\src\Handlers\ContentView\ContentViewHandler.Android.cs:line 49 at Microsoft.Maui.PropertyMapper2.<>c__DisplayClass5_0[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Handlers.IContentViewHandler, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].<Add>b__0(IElementHandler h, IElement v) in D:\a_work\1\s\src\Core\src\PropertyMapper.cs:line 183 at Microsoft.Maui.PropertyMapper.UpdatePropertyCore(String key, IElementHandler viewHandler, IElement virtualView) in D:\a_work\1\s\src\Core\src\PropertyMapper.cs:line 47 at Microsoft.Maui.PropertyMapper.UpdateProperties(IElementHandler viewHandler, IElement virtualView) in D:\a_work\1\s\src\Core\src\PropertyMapper.cs:line 82 at Microsoft.Maui.Handlers.ElementHandler.SetVirtualView(IElement view) in D:\a_work\1\s\src\Core\src\Handlers\Element\ElementHandler.cs:line 74 at Microsoft.Maui.Handlers.ViewHandler.SetVirtualView(IElement element) in D:\a_work\1\s\src\Core\src\Handlers\View\ViewHandler.cs:line 125 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.ContentViewGroup, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IView view) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 53 at Microsoft.Maui.Handlers.ContentViewHandler.SetVirtualView(IView view) in D:\a\_work\1\s\src\Core\src\Handlers\ContentView\ContentViewHandler.Android.cs:line 27 at Microsoft.Maui.Handlers.ViewHandler2[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.ContentViewGroup, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view) in D:\a_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 56 at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler) in D:\a_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 64 at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value) in D:\a_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 20 at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value) in D:\a_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:line 307 at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 105 at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context) in D:\a_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 142 at MAUIEmbedding.Droid.MainActivity.OnCreate(Bundle savedInstanceState) in C:\ws\MAUIEmbedding\MAUIEmbedding.Droid\MainActivity.cs:line 32 at Android.App.Activity.n_OnCreate_Landroid_os_Bundle_(IntPtr jnienv, IntPtr native__this, IntPtr native_savedInstanceState) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net6.0/android-32/mcw/Android.App.Activity.cs:line 2781 at Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PPL_V(_JniMarshal_PPL_V callback, IntPtr jnienv, IntPtr klazz, IntPtr p0) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:line 121