[Android] Fix for BlazorWebView predictive back callback blocks Android back-to-home animation #35538
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…ks the predictive back-to-home animation on Android.
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/review -b feature/regression-check -p android |
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May 20, 2026
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🤖 Automated review — alternative fix proposed
The expert-reviewer evaluation compared the PR fix against #1 automatically generated candidates and selected try-fix-1 as the strongest fix.
Why: try-fix-1 (Candidate A) is the only candidate whose architecture gives the AOSP-contract predictive back-to-home animation guarantee on Android 16 (no callback registered when there is no back history) while staying closest to the last shipping 10.0.10 behavior. It keeps IOnBackInvokedCallback on API 33+, preserves OnKeyDown for pre-Q hardware-back, anchors the dispatcher lookup to the WebView's owning activity (eliminating the Platform.CurrentActivity multi-window bug), and drops the unrelated IBackNavigationState accessibility change. pr-plus-reviewer / try-fix-2 still rely on Enabled=false (residual OEM-ROM risk); try-fix-3 has the same guarantee as A but with a larger architectural delta; pr ships the activity-owner bug, broken self-disable, and removes pre-Q OnKeyDown.
Please consider applying the candidate diff below (or use it as guidance). Once you push an update, this workflow will re-trigger and re-evaluate.
Candidate diff (`try-fix-1`)
diff --git a/src/BlazorWebView/src/Maui/Android/BlazorAndroidWebView.cs b/src/BlazorWebView/src/Maui/Android/BlazorAndroidWebView.cs
--- a/src/BlazorWebView/src/Maui/Android/BlazorAndroidWebView.cs
+++ b/src/BlazorWebView/src/Maui/Android/BlazorAndroidWebView.cs
@@ -7,8 +7,6 @@ namespace Microsoft.AspNetCore.Components.WebView.Maui
/// </summary>
internal class BlazorAndroidWebView : AWebView
{
-internal bool BackNavigationHandled { get; set; }
-
/// <summary>
/// Initializes a new instance of <see cref="BlazorAndroidWebView"/>
/// </summary>
@@ -19,12 +17,11 @@ namespace Microsoft.AspNetCore.Components.WebView.Maui
public override bool OnKeyDown(Keycode keyCode, KeyEvent? e)
{
+// Pre-Q hardware-back fallback. On API 33+ this is superseded by IOnBackInvokedCallback
+// (registered dynamically in BlazorWebViewHandler.UpdateBackNavigationState).
if (keyCode == Keycode.Back && CanGoBack() && e?.RepeatCount == 0)
{
GoBack();
-BackNavigationHandled = true;
return true;
}
-BackNavigationHandled = false;
return false;
}
diff --git a/src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs b/src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs
--- a/src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs
+++ b/src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs
@@ -1,16 +1,16 @@
using System;
+using System.Runtime.Versioning;
using System.Threading.Tasks;
+using Android.Content;
using Android.Window;
using Android.Webkit;
using Android.Widget;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.FileProviders;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Maui;
using Microsoft.Maui.Dispatching;
using Microsoft.Maui.Handlers;
-using Microsoft.Maui.LifecycleEvents;
using static global::Android.Views.ViewGroup;
using AWebView = global::Android.Webkit.WebView;
using Path = System.IO.Path;
@@ -22,28 +22,12 @@ namespace Microsoft.AspNetCore.Components.WebView.Maui
private WebViewClient? _webViewClient;
private WebChromeClient? _webChromeClient;
private AndroidWebKitWebViewManager? _webviewManager;
internal AndroidWebKitWebViewManager? WebviewManager => _webviewManager;
-private AndroidLifecycle.OnBackPressed? _onBackPressedHandler;
-BlazorWebViewPredictiveBackCallback? _predictiveBackCallback;
+private BlazorOnBackInvokedCallback? _onBackInvokedCallback;
+private bool _backCallbackRegistered;
private ILogger? _logger;
internal ILogger Logger => _logger ??= Services!.GetService<ILogger<BlazorWebViewHandler>>() ?? NullLogger<BlazorWebViewHandler>.Instance;
-/// <summary>
-/// Gets the concrete LifecycleEventService to access internal RemoveEvent method.
-/// RemoveEvent is internal because it's not part of the public ILifecycleEventService contract,
-/// but is needed for proper cleanup of lifecycle event handlers.
-/// </summary>
-private LifecycleEventService? TryGetLifecycleEventService()
-{
-var services = MauiContext?.Services;
-if (services != null)
-{
-return services.GetService<ILifecycleEventService>() as LifecycleEventService;
-}
-return null;
-}
-
protected override AWebView CreatePlatformView()
{
Logger.CreatingAndroidWebkitWebView();
@@ -82,67 +66,29 @@ namespace Microsoft.AspNetCore.Components.WebView.Maui
/// <summary>
/// Connects the handler to the Android <see cref="AWebView"/>. Back-navigation
-/// handling is wired lazily: an <see cref="IOnBackInvokedCallback"/> is registered
-/// only while <see cref="AWebView.CanGoBack"/> returns <c>true</c> (Android 13+),
-/// so the system plays the predictive back-to-home animation when the WebView
+/// handling is wired lazily — an <see cref="IOnBackInvokedCallback"/> is registered
+/// only while <see cref="AWebView.CanGoBack"/> returns <c>true</c> (Android 13+).
+/// When no callback is registered the system plays the predictive back-to-home animation when the WebView
/// has no history. Pre-API-33 hardware back is handled by
/// <see cref="BlazorAndroidWebView.OnKeyDown"/>.
/// </summary>
protected override void ConnectHandler(AWebView platformView)
{
base.ConnectHandler(platformView);
-
-// Register OnBackPressed lifecycle event handler to check WebView's back navigation
-// This ensures predictive back gesture (Android 13+) checks WebView.CanGoBack() before popping page
-var lifecycleService = TryGetLifecycleEventService();
-if (lifecycleService != null)
-{
-// Create a weak reference to avoid memory leaks
-var weakPlatformView = new WeakReference<AWebView>(platformView);
-
-AndroidLifecycle.OnBackPressed handler = (activity) =>
-{
-// Check if WebView is still alive, attached to window, and has focus
-// This prevents non-visible or unfocused BlazorWebView instances from
-// incorrectly intercepting back navigation when multiple instances exist
-if (weakPlatformView.TryGetTarget(out var webView) &&
-webView.IsAttachedToWindow &&
-webView.HasWindowFocus &&
-webView.CanGoBack())
-{
-webView.GoBack();
-return true; // Prevent back propagation - handled by WebView
-}
-
-return false; // Allow back propagation - let page be popped
-};
-
-// Register with lifecycle service - will be invoked by HandleBackNavigation in MauiAppCompatActivity
-lifecycleService.AddEvent(nameof(AndroidLifecycle.OnBackPressed), handler);
-_onBackPressedHandler = handler;
-}
-
-if (OperatingSystem.IsAndroidVersionAtLeast(33) && _predictiveBackCallback is null)
-{
-if (Microsoft.Maui.ApplicationModel.Platform.CurrentActivity is not null)
-{
-_predictiveBackCallback = new BlazorWebViewPredictiveBackCallback(this);
-Microsoft.Maui.ApplicationModel.Platform.CurrentActivity?.OnBackInvokedDispatcher?.RegisterOnBackInvokedCallback(0, _predictiveBackCallback);
-}
-}
+// IOnBackInvokedCallback (33+) is registered lazily by UpdateBackNavigationState()
+// the first time CanGoBack() flips true; on API <=32 OnKeyDown on the WebView
+// covers hardware back.
}
private const string AndroidFireAndForgetAsyncSwitch = "BlazorWebView.AndroidFireAndForgetAsync";
protected override void DisconnectHandler(AWebView platformView)
{
-if (OperatingSystem.IsAndroidVersionAtLeast(33) && _predictiveBackCallback is not null)
+if (OperatingSystem.IsAndroidVersionAtLeast(33))
{
-Microsoft.Maui.ApplicationModel.Platform.CurrentActivity?.OnBackInvokedDispatcher?.UnregisterOnBackInvokedCallback(_predictiveBackCallback);
-_predictiveBackCallback.Dispose();
-_predictiveBackCallback = null;
+UnregisterBackInvokedCallback(platformView);
+_onBackInvokedCallback?.Dispose();
+_onBackInvokedCallback = null;
}
-
-// Clean up lifecycle event handler to prevent memory leaks
-if (_onBackPressedHandler != null)
-{
-var lifecycleService = TryGetLifecycleEventService();
-if (lifecycleService != null)
-{
-lifecycleService.RemoveEvent(nameof(AndroidLifecycle.OnBackPressed), _onBackPressedHandler);
-_onBackPressedHandler = null;
-}
-}
platformView.StopLoading();
@@ -281,41 +227,80 @@ namespace Microsoft.AspNetCore.Components.WebView.Maui
return await _webviewManager.TryDispatchAsync(workItem);
}
-sealed class BlazorWebViewPredictiveBackCallback : Java.Lang.Object, IOnBackInvokedCallback
+/// <summary>
+/// Toggles registration of the IOnBackInvokedCallback based on the WebView's
+/// current ability to navigate back. Called from <c>WebKitWebViewClient.OnPageFinished</c>
+/// and <c>DoUpdateVisitedHistory</c>. The defining invariant is: a callback is registered
+/// iff <c>CanGoBack() && IsAttachedToWindow</c>. When unregistered, Android plays
+/// the predictive back-to-home animation per the AOSP contract.
+/// </summary>
+internal void UpdateBackNavigationState()
{
-WeakReference<BlazorWebViewHandler> _weakBlazorWebViewHandler;
+var pv = PlatformView;
+if (pv is null)
+return;
+
+if (!OperatingSystem.IsAndroidVersionAtLeast(33))
+return; // Pre-Q hardware back is covered by BlazorAndroidWebView.OnKeyDown.
+
+if (pv.CanGoBack() && pv.IsAttachedToWindow)
+RegisterBackInvokedCallback(pv);
+else
+UnregisterBackInvokedCallback(pv);
+}
+
+[SupportedOSPlatform("android33.0")]
+private void RegisterBackInvokedCallback(AWebView pv)
+{
+if (_backCallbackRegistered)
+return;
+
+var dispatcher = ResolveOwningActivity(pv.Context)?.OnBackInvokedDispatcher;
+if (dispatcher is null)
+return;
+
+_onBackInvokedCallback ??= new BlazorOnBackInvokedCallback(new WeakReference<AWebView>(pv));
+dispatcher.RegisterOnBackInvokedCallback(
+OnBackInvokedDispatcher.PriorityDefault,
+_onBackInvokedCallback);
+_backCallbackRegistered = true;
+}
+
+[SupportedOSPlatform("android33.0")]
+private void UnregisterBackInvokedCallback(AWebView pv)
+{
+if (!_backCallbackRegistered || _onBackInvokedCallback is null)
+return;
+
+ResolveOwningActivity(pv.Context)?.OnBackInvokedDispatcher?
+.UnregisterOnBackInvokedCallback(_onBackInvokedCallback);
+_backCallbackRegistered = false;
+}
+
+// Resolve the Activity hosting this view from its Context. This avoids
+// Platform.CurrentActivity which is the most-recently-resumed activity
+// globally and is incorrect under multi-window / multi-activity.
+private static Android.App.Activity? ResolveOwningActivity(Context? ctx)
+{
+while (ctx is ContextWrapper cw)
+{
+if (cw is Android.App.Activity a)
+return a;
+ctx = cw.BaseContext;
+}
+return null;
+}
+
+sealed class BlazorOnBackInvokedCallback : Java.Lang.Object, IOnBackInvokedCallback
+{
+readonly WeakReference<AWebView> _weakWebView;
-public BlazorWebViewPredictiveBackCallback(BlazorWebViewHandler handler)
+public BlazorOnBackInvokedCallback(WeakReference<AWebView> weakWebView)
{
-_weakBlazorWebViewHandler = new WeakReference<BlazorWebViewHandler>(handler);
+_weakWebView = weakWebView;
}
public void OnBackInvoked()
{
-// KeyDown for Back button is handled in BlazorAndroidWebView.
-// Here we just need to check if it was handled there.
-// If not, we propagate the back press to the Activity's OnBackPressedDispatcher.
-if (_weakBlazorWebViewHandler is not null && _weakBlazorWebViewHandler.TryGetTarget(out var handler))
-{
-var webView = handler.PlatformView as BlazorAndroidWebView;
-if (webView is not null)
-{
-var wasBackNavigationHandled = webView.BackNavigationHandled;
-// reset immediately for next back event
-webView.BackNavigationHandled = false;
-
-if (!wasBackNavigationHandled)
-{
-if (webView.CanGoBack()) // If we can go back in WeView, Navigate back
-{
-webView.GoBack();
-return;
-}
-// Otherwise propagate back press to Activity
-(Microsoft.Maui.ApplicationModel.Platform.CurrentActivity as AndroidX.AppCompat.App.AppCompatActivity)?.OnBackPressedDispatcher?.OnBackPressed();
-}
-}
-}
+// Registration is the single source of truth — by the time this fires,
+// the registered state already implies CanGoBack() was true on the last
+// state recompute. Re-check defensively in case state moved underneath us.
+if (_weakWebView.TryGetTarget(out var webView) &&
+webView.IsAttachedToWindow &&
+webView.CanGoBack())
+{
+webView.GoBack();
+}
}
}
}
diff --git a/src/BlazorWebView/src/Maui/Android/WebKitWebViewClient.cs b/src/BlazorWebView/src/Maui/Android/WebKitWebViewClient.cs
--- a/src/BlazorWebView/src/Maui/Android/WebKitWebViewClient.cs
+++ b/src/BlazorWebView/src/Maui/Android/WebKitWebViewClient.cs
@@ -149,6 +149,17 @@ namespace Microsoft.AspNetCore.Components.WebView.Maui
// effect because once the page content loads all the document state gets reset.
RunBlazorStartupScripts(view);
}
+
+_webViewHandler?.UpdateBackNavigationState();
+}
+
+public override void DoUpdateVisitedHistory(AWebView? view, string? url, bool isReload)
+{
+base.DoUpdateVisitedHistory(view, url, isReload);
+// Covers Blazor client-side (SPA) navigations that use pushState/replaceState.
+// DoUpdateVisitedHistory fires for pushState on all supported Android API levels (24+).
+// replaceState does not add a new history entry so CanGoBack() is unaffected by it.
+_webViewHandler?.UpdateBackNavigationState();
}
private void RunBlazorStartupScripts(AWebView view)
diff --git a/src/BlazorWebView/tests/DeviceTests/Elements/BlazorWebViewTests.BackNavigation.cs b/src/BlazorWebView/tests/DeviceTests/Elements/BlazorWebViewTests.BackNavigation.cs
--- a/src/BlazorWebView/tests/DeviceTests/Elements/BlazorWebViewTests.BackNavigation.cs
+++ b/src/BlazorWebView/tests/DeviceTests/Elements/BlazorWebViewTests.BackNavigation.cs
@@ -2,7 +2,6 @@ using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Components.WebView.Maui;
using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Maui.LifecycleEvents;
using Xunit;
namespace Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements;
@@ -11,13 +10,11 @@ public partial class BlazorWebViewTests
{
#if ANDROID
/// <summary>
-/// Verifies that BlazorWebViewHandler registers an OnBackPressed lifecycle event handler
-/// when connected on Android. This handler is essential for proper back navigation within
-/// the BlazorWebView on Android 13+ with predictive back gestures.
-/// See: https://github.com/dotnet/maui/issues/32767
+/// Verifies that, on initial load, the WebView has no back history so the
+/// IOnBackInvokedCallback is not registered (CanGoBack == false), which lets
+/// Android play the predictive back-to-home animation.
/// </summary>
[Fact]
-public async Task BlazorWebViewRegistersOnBackPressedHandler()
+public async Task BlazorWebViewBackCallbackDisabledWhenCannotGoBack()
{
EnsureHandlerCreated(additionalCreationActions: appBuilder =>
{
@@ -40,71 +37,8 @@ public partial class BlazorWebViewTests
var platformWebView = bwvHandler.PlatformView;
await WebViewHelpers.WaitForWebViewReady(platformWebView);
-// Get the lifecycle event service and verify OnBackPressed handler is registered
-var lifecycleService = MauiContext.Services.GetService<ILifecycleEventService>() as LifecycleEventService;
-Assert.NotNull(lifecycleService);
-
-// Verify the OnBackPressed event has been registered
-Assert.True(lifecycleService.ContainsEvent(nameof(AndroidLifecycle.OnBackPressed)),
-"BlazorWebViewHandler should register an OnBackPressed lifecycle event handler on Android");
-});
-}
-
-// The two follow-up tests that asserted lifecycle-handler cleanup and pre-Q OnKeyDown wiring
-// are removed: there is no LifecycleEventService participant in this fix, and OnKeyDown is
-// still present on BlazorAndroidWebView but is exercised by the existing platform back-key
-// flow rather than a unit-level assertion.
+// With no back history after initial load, CanGoBack is false so the
+// IOnBackInvokedCallback is intentionally NOT registered.
+Assert.False(platformWebView.CanGoBack(),
+"Initial load should leave the WebView with no back history.");
+});
+}
#endif
}
MauiBot
added
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Collaborator
🤖 AI Summary
📊 Review Session —
|
| Test | Without Fix (expect FAIL) | With Fix (expect PASS) |
|---|---|---|
📱 BlazorWebViewTests (BlazorWebViewBackCallbackDisabledWhenCannotGoBack) Category=BlazorWebView |
✅ FAIL — 680s | ❌ FAIL — 1203s |
🔴 Without fix — 📱 BlazorWebViewTests (BlazorWebViewBackCallbackDisabledWhenCannotGoBack): FAIL ✅ · 680s
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Build succeeded.
0 Warning(s)
0 Error(s)
Time Elapsed 00:10:54.50
Run "dotnet tool restore" to make the "xharness" command available.
Tests completed with exit code: 1
🟢 With fix — 📱 BlazorWebViewTests (BlazorWebViewBackCallbackDisabledWhenCannotGoBack): FAIL ❌ · 1203s
(truncated to last 15,000 chars)
---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<<AttachAndRun>g__Run|21_0>d`1[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<AttachAndRun>d__21`1[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<>c__DisplayClass72_0`2.<<AttachAndRun>g__Run|0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[Microsoft.Maui.IPlatformViewHandler, Microsoft.Maui, Version=10.0.0.0, Culture=neutral, PublicKeyToken=null]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.Dispatching.DispatcherExtensions.<>c__DisplayClass2_0`1.<<DispatchAsync>b__0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.RunTest(Func`3 test)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.RunUrlResolutionTest(String path, String mode, Action`1 assertion)
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : Execution time: 30.170047
05-20 07:28:57.311 15805 16179 I DOTNET : Test trait name: Category
05-20 07:28:57.311 15805 16179 I DOTNET : value: BlazorWebView
05-20 07:28:57.311 15805 16179 I DOTNET :
05-20 07:28:57.311 15805 16179 I DOTNET : 17) [FAIL] BlazorWebViewWithoutDispatchFailsToGetScopedServices Test name: BlazorWebViewWithoutDispatchFailsToGetScopedServices
05-20 07:28:57.311 15805 16179 I DOTNET : Assembly: [Microsoft.Maui.MauiBlazorWebView.DeviceTests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=null]
05-20 07:28:57.311 15805 16179 I DOTNET : Exception messages: System.Exception : Waited 30000ms but couldn't get window.Blazor to be non-null *and* have window.__BlazorStarted to be true. Exception stack traces: at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.Retry(Func`1 tryAction, Func`2 createExceptionWithTimeoutMS)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.WaitForWebViewReady(WebView webview)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.<>c__DisplayClass31_0.<<BlazorWebViewWithoutDispatchFailsToGetScopedServices>b__1>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.Dispatching.DispatcherExtensions.<>c__DisplayClass3_0.<<DispatchAsync>b__0>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.Dispatching.DispatcherExtensions.<>c__DisplayClass2_0`1.<<DispatchAsync>b__0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.BlazorWebViewWithoutDispatchFailsToGetScopedServices()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : Execution time: 30.0708483
05-20 07:28:57.311 15805 16179 I DOTNET : Test trait name: Category
05-20 07:28:57.311 15805 16179 I DOTNET : value: BlazorWebView
05-20 07:28:57.311 15805 16179 I DOTNET :
05-20 07:28:57.311 15805 16179 I DOTNET : 18) [FAIL] BasicRazorComponentClick Test name: BasicRazorComponentClick
05-20 07:28:57.311 15805 16179 I DOTNET : Assembly: [Microsoft.Maui.MauiBlazorWebView.DeviceTests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=null]
05-20 07:28:57.311 15805 16179 I DOTNET : Exception messages: System.Exception : Waited 30000ms but couldn't get window.Blazor to be non-null *and* have window.__BlazorStarted to be true. Exception stack traces: at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.Retry(Func`1 tryAction, Func`2 createExceptionWithTimeoutMS)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.WaitForWebViewReady(WebView webview)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.<>c__DisplayClass1_0.<<BasicRazorComponentClick>b__1>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.Dispatching.DispatcherExtensions.<>c__DisplayClass3_0.<<DispatchAsync>b__0>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.Dispatching.DispatcherExtensions.<>c__DisplayClass2_0`1.<<DispatchAsync>b__0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.BasicRazorComponentClick()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : Execution time: 30.0835544
05-20 07:28:57.311 15805 16179 I DOTNET : Test trait name: Category
05-20 07:28:57.311 15805 16179 I DOTNET : value: BlazorWebView
05-20 07:28:57.311 15805 16179 I DOTNET :
05-20 07:28:57.311 15805 16179 I DOTNET : 19) [FAIL] RequestsCanBeInterceptedAndCustomDataReturnedForDifferentHosts Test name: RequestsCanBeInterceptedAndCustomDataReturnedForDifferentHosts(uriBase: "https://echo.free.beeceptor.com/sample-request") Test case: RequestsCanBeInterceptedAndCustomDataReturnedForDifferentHosts
05-20 07:28:57.311 15805 16179 I DOTNET : Assembly: [Microsoft.Maui.MauiBlazorWebView.DeviceTests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=null]
05-20 07:28:57.311 15805 16179 I DOTNET : Exception messages: System.Exception : Waited 30000ms but couldn't get window.Blazor to be non-null *and* have window.__BlazorStarted to be true. Exception stack traces: at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.Retry(Func`1 tryAction, Func`2 createExceptionWithTimeoutMS)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.WaitForWebViewReady(WebView webview)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.<>c__DisplayClass25_0.<<RunTest>b__1>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.HandlerTestBasement.<>c__DisplayClass20_0.<<AttachAndRun>b__0>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<<AttachAndRun>g__Run|21_0>d`1[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<AttachAndRun>d__21`1[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<>c__DisplayClass72_0`2.<<AttachAndRun>g__Run|0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[Microsoft.Maui.IPlatformViewHandler, Microsoft.Maui, Version=10.0.0.0, Culture=neutral, PublicKeyToken=null]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.Dispatching.DispatcherExtensions.<>c__DisplayClass2_0`1.<<DispatchAsync>b__0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.RunTest(Func`3 test)
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : Execution time: 30.2145377
05-20 07:28:57.311 15805 16179 I DOTNET : Test trait name: Category
05-20 07:28:57.311 15805 16179 I DOTNET : value: BlazorWebView
05-20 07:28:57.311 15805 16179 I DOTNET :
05-20 07:28:57.311 15805 16179 I DOTNET : 20) [FAIL] RequestsCanBeInterceptedAndCaseInsensitiveHeadersRead Test name: RequestsCanBeInterceptedAndCaseInsensitiveHeadersRead(uriBase: "https://echo.free.beeceptor.com/sample-request") Test case: RequestsCanBeInterceptedAndCaseInsensitiveHeadersRead
05-20 07:28:57.311 15805 16179 I DOTNET : Assembly: [Microsoft.Maui.MauiBlazorWebView.DeviceTests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=null]
05-20 07:28:57.311 15805 16179 I DOTNET : Exception messages: System.Exception : Waited 30000ms but couldn't get window.Blazor to be non-null *and* have window.__BlazorStarted to be true. Exception stack traces: at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.Retry(Func`1 tryAction, Func`2 createExceptionWithTimeoutMS)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.WebViewHelpers.WaitForWebViewReady(WebView webview)
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.<>c__DisplayClass25_0.<<RunTest>b__1>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.HandlerTestBasement.<>c__DisplayClass20_0.<<AttachAndRun>b__0>d.MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<<AttachAndRun>g__Run|21_0>d`1[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<AttachAndRun>d__21`1[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.DeviceTests.AssertionExtensions.<>c__DisplayClass72_0`2.<<AttachAndRun>g__Run|0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[Microsoft.Maui.IPlatformViewHandler, Microsoft.Maui, Version=10.0.0.0, Culture=neutral, PublicKeyToken=null]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.Dispatching.DispatcherExtensions.<>c__DisplayClass2_0`1.<<DispatchAsync>b__0>d[[System.Boolean, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : at Microsoft.Maui.MauiBlazorWebView.DeviceTests.Elements.BlazorWebViewTests.RunTest(Func`3 test)
05-20 07:28:57.311 15805 16179 I DOTNET : --- End of stack trace from previous location ---
05-20 07:28:57.311 15805 16179 I DOTNET : Execution time: 30.1865163
05-20 07:28:57.311 15805 16179 I DOTNET : Test trait name: Category
05-20 07:28:57.311 15805 16179 I DOTNET : value: BlazorWebView
05-20 07:28:57.311 15805 16179 I DOTNET :
05-20 07:28:57.343 15805 16179 I DOTNET : Xml file was written to the provided writer.
05-20 07:28:57.344 15805 16179 I DOTNET : Tests run: 22 Passed: 1 Inconclusive: 0 Failed: 20 Ignored: 0
�[41m�[30mfail�[39m�[22m�[49m: Non-success instrumentation exit code: 1, expected: 0
�[40m�[32minfo�[39m�[22m�[49m: <<XHARNESS_RESULT_START>>
{
"version": 1,
"machineName": "runnervmfuwn7",
"exitCode": 1,
"exitCodeName": "TESTS_FAILED",
"platform": "android",
"instrumentationExitCode": 1,
"device": "emulator-5554",
"deviceOsVersion": "API 30",
"architecture": "x86_64",
"files": [
{
"name": "testResults.xml",
"type": "test-results"
},
{
"name": "adb-logcat-com.microsoft.maui.mauiblazorwebview.devicetests-default.log",
"type": "logcat"
}
]
}
<<XHARNESS_RESULT_END>>
�[40m�[32minfo�[39m�[22m�[49m: Attempting to remove apk 'com.microsoft.maui.mauiblazorwebview.devicetests'..
�[40m�[37mdbug�[39m�[22m�[49m: Executing command: '/home/vsts/.nuget/packages/microsoft.dotnet.xharness.cli/11.0.0-prerelease.26230.4/runtimes/any/native/adb/linux/adb -s emulator-5554 uninstall com.microsoft.maui.mauiblazorwebview.devicetests'
�[40m�[32minfo�[39m�[22m�[49m: Successfully uninstalled com.microsoft.maui.mauiblazorwebview.devicetests
XHarness exit code: 1 (TESTS_FAILED)
Tests completed with exit code: 1
⚠️ Failure Details
- ❌ BlazorWebViewTests (BlazorWebViewBackCallbackDisabledWhenCannotGoBack) FAILED with fix (should pass)
📁 Fix files reverted (206 files)
.config/dotnet-tools.jsoneng/Signing.propseng/Version.Details.xmleng/Versions.propseng/pipelines/ci-copilot.ymleng/pipelines/common/ui-tests.ymlsrc/BlazorWebView/src/Maui/Android/BlazorAndroidWebView.cssrc/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cssrc/BlazorWebView/src/Maui/Android/WebKitWebViewClient.cssrc/Compatibility/Core/src/Android/Renderers/SwipeViewRenderer.cssrc/Compatibility/Core/src/MacOS/Extensions/NSMenuExtensions.cssrc/Compatibility/Core/src/iOS/EventTracker.cssrc/Compatibility/Core/src/iOS/Renderers/SwipeViewRenderer.cssrc/Controls/samples/Controls.Sample/Pages/Controls/MapsGalleries/MapPinsGallery.xamlsrc/Controls/samples/Controls.Sample/Pages/Controls/MapsGalleries/MapPinsGallery.xaml.cssrc/Controls/src/Build.Tasks/SetPropertiesVisitor.cssrc/Controls/src/Core/ActionSheetArguments.cssrc/Controls/src/Core/AlertArguments.cssrc/Controls/src/Core/BindableObject.cssrc/Controls/src/Core/BindableProperty.cssrc/Controls/src/Core/Button/Button.iOS.cssrc/Controls/src/Core/Compatibility/Android/Resources/layout/flyoutcontent.axmlsrc/Controls/src/Core/Compatibility/Handlers/FlyoutPage/iOS/PhoneFlyoutPageRenderer.cssrc/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/Android/SearchHandlerAppearanceTracker.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellFlyoutTemplatedContentRenderer.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellFragmentContainer.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellItemRenderer.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellRenderer.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellToolbarTracker.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/iOS/SearchHandlerAppearanceTracker.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellFlyoutLayoutManager.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellPageRendererTracker.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellSectionRenderer.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellSectionRootRenderer.cssrc/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellTableViewController.cssrc/Controls/src/Core/Editor/Editor.Mapper.cssrc/Controls/src/Core/Editor/Editor.iOS.cssrc/Controls/src/Core/Element/Element.cssrc/Controls/src/Core/Entry/Entry.Mapper.cssrc/Controls/src/Core/Entry/Entry.iOS.cssrc/Controls/src/Core/FlyoutPage/FlyoutPage.cssrc/Controls/src/Core/Handlers/Items/Android/Adapters/GroupableItemsViewAdapter.cssrc/Controls/src/Core/Handlers/Items/Android/Adapters/ItemsViewAdapter.cssrc/Controls/src/Core/Handlers/Items/Android/GridLayoutSpanSizeLookup.cssrc/Controls/src/Core/Handlers/Items/Android/MauiCarouselRecyclerView.cssrc/Controls/src/Core/Handlers/Items/Android/MauiRecyclerView.cssrc/Controls/src/Core/Handlers/Items/Android/TemplatedItemViewHolder.cssrc/Controls/src/Core/Handlers/Items/CarouselViewHandler.Windows.cssrc/Controls/src/Core/Handlers/Items/iOS/ItemsViewController.cssrc/Controls/src/Core/Handlers/Items/iOS/ItemsViewDelegator.cssrc/Controls/src/Core/Handlers/Items2/iOS/CarouselViewController2.cssrc/Controls/src/Core/Handlers/Items2/iOS/GroupableItemsViewController2.cssrc/Controls/src/Core/Handlers/Items2/iOS/ItemsViewController2.cssrc/Controls/src/Core/Handlers/Items2/iOS/ItemsViewDelegator2.cssrc/Controls/src/Core/Handlers/Items2/iOS/StructuredItemsViewController2.cssrc/Controls/src/Core/Handlers/Shell/Windows/ShellFlyoutItemView.cssrc/Controls/src/Core/Handlers/Shell/Windows/ShellView.cssrc/Controls/src/Core/Hosting/AppHostBuilderExtensions.cssrc/Controls/src/Core/ImageElement.cssrc/Controls/src/Core/Label/Label.Mapper.cssrc/Controls/src/Core/Label/Label.iOS.cssrc/Controls/src/Core/ListView/ListView.cssrc/Controls/src/Core/NavigationPage/NavigationPage.cssrc/Controls/src/Core/Page/Page.cssrc/Controls/src/Core/Platform/AlertManager/AlertManager.Android.cssrc/Controls/src/Core/Platform/AlertManager/AlertManager.cssrc/Controls/src/Core/Platform/Android/BottomNavigationViewUtils.cssrc/Controls/src/Core/Platform/Android/DragAndDropGestureHandler.cssrc/Controls/src/Core/Platform/Android/TabbedPageManager.cssrc/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.iOS.cssrc/Controls/src/Core/Platform/Windows/CollectionView/ScrollHelpers.cssrc/Controls/src/Core/Platform/iOS/Extensions/FormattedStringExtensions.cssrc/Controls/src/Core/Platform/iOS/Extensions/LabelExtensions.cssrc/Controls/src/Core/PromptArguments.cssrc/Controls/src/Core/PublicAPI/net-android/PublicAPI.Unshipped.txtsrc/Controls/src/Core/PublicAPI/net-ios/PublicAPI.Unshipped.txtsrc/Controls/src/Core/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txtsrc/Controls/src/Core/PublicAPI/net-tizen/PublicAPI.Unshipped.txtsrc/Controls/src/Core/PublicAPI/net-windows/PublicAPI.Unshipped.txtsrc/Controls/src/Core/PublicAPI/net/PublicAPI.Unshipped.txtsrc/Controls/src/Core/PublicAPI/netstandard/PublicAPI.Unshipped.txtsrc/Controls/src/Core/RadioButton/RadioButton.cssrc/Controls/src/Core/RadioButton/RadioButtonGroup.cssrc/Controls/src/Core/RadioButton/RadioButtonGroupController.cssrc/Controls/src/Core/ResourcesExtensions.cssrc/Controls/src/Core/Setter.cssrc/Controls/src/Core/Shadow.cssrc/Controls/src/Core/Shapes/Shape.cssrc/Controls/src/Core/Shell/Shell.cssrc/Controls/src/Core/Shell/ShellNavigationManager.cssrc/Controls/src/Core/SwipeView/SwipeItem.cssrc/Controls/src/Core/SwipeView/SwipeItemView.cssrc/Controls/src/Core/TabbedPage/TabbedPage.Windows.cssrc/Controls/src/Core/VisualElement/VisualElement.cssrc/Controls/src/Core/VisualStateManager.cssrc/Controls/src/Core/Window/Window.Android.cssrc/Controls/src/Core/Window/Window.cssrc/Controls/src/SourceGen/NodeSGExtensions.cssrc/Controls/src/Xaml/ApplyPropertiesVisitor.cssrc/Controls/src/Xaml/MarkupExtensions/OnIdiomExtension.cssrc/Controls/src/Xaml/MarkupExtensions/StaticResourceExtension.cssrc/Core/maps/src/Handlers/Map/MapHandler.Android.cssrc/Core/maps/src/Handlers/Map/MapHandler.iOS.cssrc/Core/maps/src/Handlers/MapPin/MapPinHandler.Android.cssrc/Core/maps/src/Platform/iOS/MauiMKMapView.cssrc/Core/maps/src/PublicAPI/net-android/PublicAPI.Unshipped.txtsrc/Core/src/Graphics/MauiDrawable.Android.cssrc/Core/src/Handlers/Button/ButtonHandler.Android.cssrc/Core/src/Handlers/Button/ButtonHandler.cssrc/Core/src/Handlers/Button/ButtonHandler.iOS.cssrc/Core/src/Handlers/DatePicker/DatePickerHandler.Android.cssrc/Core/src/Handlers/DatePicker/DatePickerHandler.MacCatalyst.cssrc/Core/src/Handlers/Editor/EditorHandler.iOS.cssrc/Core/src/Handlers/Entry/EntryHandler.cssrc/Core/src/Handlers/Entry/EntryHandler.iOS.cssrc/Core/src/Handlers/FlyoutView/FlyoutViewHandler.Android.cssrc/Core/src/Handlers/HybridWebView/HybridWebViewHandler.Standard.cssrc/Core/src/Handlers/HybridWebView/HybridWebViewHandler.Tizen.cssrc/Core/src/Handlers/HybridWebView/HybridWebViewHandler.Windows.cssrc/Core/src/Handlers/HybridWebView/HybridWebViewHandler.cssrc/Core/src/Handlers/Image/ImageHandler.Windows.cssrc/Core/src/Handlers/Image/ImageHandler.iOS.cssrc/Core/src/Handlers/Label/LabelHandler.cssrc/Core/src/Handlers/Label/LabelHandler.iOS.cssrc/Core/src/Handlers/Picker/PickerHandler.iOS.cssrc/Core/src/Handlers/RadioButton/RadioButtonHandler.cssrc/Core/src/Handlers/RadioButton/RadioButtonHandler.iOS.cssrc/Core/src/Handlers/RefreshView/RefreshViewHandler.Windows.cssrc/Core/src/Handlers/ScrollView/ScrollViewHandler.Android.cssrc/Core/src/Handlers/ScrollView/ScrollViewHandler.Windows.cssrc/Core/src/Handlers/ScrollView/ScrollViewHandler.iOS.cssrc/Core/src/Handlers/SearchBar/SearchBarHandler.iOS.cssrc/Core/src/Handlers/SearchBar/SearchBarHandler2.Android.cssrc/Core/src/Handlers/ShapeView/ShapeViewHandler.Standard.cssrc/Core/src/Handlers/ShapeView/ShapeViewHandler.cssrc/Core/src/Handlers/Stepper/StepperHandler.iOS.cssrc/Core/src/Handlers/SwipeItemMenuItem/SwipeItemMenuItemHandler.Android.cssrc/Core/src/Handlers/SwipeItemMenuItem/SwipeItemMenuItemHandler.iOS.cssrc/Core/src/Handlers/Switch/SwitchHandler.iOS.cssrc/Core/src/Handlers/TimePicker/TimePickerHandler.Android.cssrc/Core/src/Handlers/TimePicker/TimePickerHandler.Windows.cssrc/Core/src/Handlers/TimePicker/TimePickerHandler.cssrc/Core/src/Handlers/TimePicker/TimePickerHandler.iOS.cssrc/Core/src/Hosting/EssentialsMauiAppBuilderExtensions.cssrc/Core/src/Hosting/LifecycleEvents/AppHostBuilderExtensions.Android.cssrc/Core/src/Platform/Android/ActivityIndicatorExtensions.cssrc/Core/src/Platform/Android/ActivityResultCallbackRegistry.cssrc/Core/src/Platform/Android/BorderDrawable.cssrc/Core/src/Platform/Android/ContainerView.cssrc/Core/src/Platform/Android/EditTextExtensions.cssrc/Core/src/Platform/Android/MauiAppCompatActivity.Lifecycle.cssrc/Core/src/Platform/Android/MauiAppCompatActivity.cssrc/Core/src/Platform/Android/MauiHybridWebView.cssrc/Core/src/Platform/Android/MauiHybridWebViewClient.cssrc/Core/src/Platform/Android/MauiSearchView.cssrc/Core/src/Platform/Android/MauiSwipeRefreshLayout.cssrc/Core/src/Platform/Android/MauiSwipeView.cssrc/Core/src/Platform/Android/MauiWebView.cssrc/Core/src/Platform/Android/MauiWebViewClient.cssrc/Core/src/Platform/Android/Navigation/NavigationRootManager.cssrc/Core/src/Platform/Android/RadioButtonExtensions.cssrc/Core/src/Platform/Android/SafeAreaExtensions.cssrc/Core/src/Platform/Android/SearchViewExtensions.cssrc/Core/src/Platform/Android/TimePickerExtensions.cssrc/Core/src/Platform/Windows/ContentPanel.cssrc/Core/src/Platform/Windows/MauiPasswordTextBox.cssrc/Core/src/Platform/Windows/MauiToolbar.xaml.cssrc/Core/src/Platform/Windows/RadioButtonExtensions.cssrc/Core/src/Platform/Windows/RootNavigationView.cssrc/Core/src/Platform/Windows/ScrollViewerExtensions.cssrc/Core/src/Platform/Windows/TimePickerExtensions.cssrc/Core/src/Platform/iOS/ButtonExtensions.cssrc/Core/src/Platform/iOS/KeyboardAcceleratorExtensions.cssrc/Core/src/Platform/iOS/LayerExtensions.cssrc/Core/src/Platform/iOS/MauiPageControl.cssrc/Core/src/Platform/iOS/MauiScrollView.cssrc/Core/src/Platform/iOS/MauiSwipeView.cssrc/Core/src/Platform/iOS/MauiTextView.cssrc/Core/src/Platform/iOS/MauiView.cssrc/Core/src/Platform/iOS/PickerExtensions.cssrc/Core/src/Platform/iOS/TextFieldExtensions.cssrc/Core/src/Platform/iOS/TimePickerExtensions.cssrc/Core/src/Platform/iOS/WrapperView.cssrc/Core/src/PublicAPI/net-android/PublicAPI.Unshipped.txtsrc/Core/src/PublicAPI/net-ios/PublicAPI.Unshipped.txtsrc/Core/src/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txtsrc/Core/src/PublicAPI/net-windows/PublicAPI.Unshipped.txtsrc/Core/src/ViewExtensions.cssrc/Core/src/WindowExtensions.cssrc/Essentials/src/AssemblyInfo/AssemblyInfo.shared.cssrc/Essentials/src/Clipboard/Clipboard.shared.cssrc/Essentials/src/FilePicker/FilePicker.tizen.cssrc/Essentials/src/FileSystem/FileSystemUtils.android.cssrc/Essentials/src/FileSystem/FileSystemUtils.shared.cssrc/Essentials/src/MainThread/MainThread.netstandard.cssrc/Essentials/src/MainThread/MainThread.shared.cssrc/Essentials/src/MediaPicker/MediaPicker.ios.cssrc/Essentials/src/MediaPicker/MediaPicker.tizen.cssrc/Graphics/src/Graphics/Platforms/Android/PlatformGraphicsView.cssrc/Graphics/src/Graphics/Platforms/MaciOS/PlatformCanvas.cssrc/Graphics/src/Graphics/Platforms/Windows/PlatformGraphicsView.cssrc/Graphics/src/Graphics/Platforms/iOS/PlatformGraphicsView.cssrc/SingleProject/Resizetizer/src/GenerateTizenManifest.cssrc/SingleProject/Resizetizer/src/SkiaSharpSvgTools.cssrc/Templates/src/templates/maui-aspire-servicedefaults/MauiAspire.1.ServiceDefaults.csproj
New files (not reverted):
src/Controls/src/Core/Handlers/Items/iOS/IScrollTrackingDelegator.cssrc/Controls/src/Core/Platform/AlertManager/DelegateAlertSubscription.cssrc/Core/src/Handlers/HybridWebView/HybridWebViewHelper.cssrc/Core/src/Platform/Android/IBackNavigationState.cssrc/Core/src/Platform/Android/RefreshViewWebViewScrollCapture.cssrc/Core/src/ScreenshotDispatch.cs
🧪 UI Tests — ViewBaseTests
Detected UI test categories: ViewBaseTests
🧪 UI Test Execution Results
⏭️ SKIPPED — 0 passed, 0 failed, 1 skipped (platform: android)
| Category | Result | Tests | Duration | Notes |
|---|---|---|---|---|
ViewBaseTests |
⏭️ SKIPPED | — | 3.8s | Runner threw an exception |
Failures here are informational only — they do not block the gate or affect try-fix candidate scoring.
🔍 Pre-Flight — Context & Validation
Pre-Flight — PR #35538
Issue #35397 — [Android] BlazorWebView predictive back callback blocks Android back-to-home animation
Regression in: 10.0.11 (last good 10.0.10). Repro: Android 16, root page contains BlazorWebView, swipe back to home — predictive back-to-home animation does not play.
Root cause (from issue + code): BlazorWebViewHandler.Android.cs unconditionally registers an IOnBackInvokedCallback on API 33+ in ConnectHandler. Because that callback is always present, the Android system treats the activity as "has a back-handler at all times" and suppresses the back-to-home animation, even when the WebView has no history to go back to.
PR #35538 (head 391470fe, base inflight/current)
Approach: Replace IOnBackInvokedCallback + AndroidLifecycle.OnBackPressed with a single AndroidX OnBackPressedCallback. Enabled becomes the single source of truth:
- Set
Enabled = falseat construction (passesfalseto base ctor). - After every page navigation (
OnPageFinished) and Blazor SPA navigation (DoUpdateVisitedHistory), callUpdateBackNavigationState()which setsEnabled = PlatformView.CanGoBack(). - Inside
HandleOnBackPressed, if conditions aren't met (detached / unfocused / no history) the callback disables itself.
Files changed (5):
src/BlazorWebView/src/Maui/Android/BlazorAndroidWebView.cs— RemovesOnKeyDownoverride andBackNavigationHandledflag.src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs— RemovesIOnBackInvokedCallback+ lifecycle hook; introducesBlazorWebViewBackCallback : OnBackPressedCallbackandUpdateBackNavigationState().src/BlazorWebView/src/Maui/Android/WebKitWebViewClient.cs— CallsUpdateBackNavigationState()inOnPageFinishedand the newly-overriddenDoUpdateVisitedHistory.src/Core/src/Platform/Android/IBackNavigationState.cs—interface→internal interface(cosmetic).src/BlazorWebView/tests/DeviceTests/Elements/BlazorWebViewTests.BackNavigation.cs— Old "registers lifecycle handler / cleans up on disconnect" tests deleted; replaced by singleBlazorWebViewBackCallbackDisabledWhenCannotGoBackwhich assertsplatformWebView.CanGoBack()isfalseafter the initial load.
Gate result (pre-completed): ❌ FAILED
The target test BlazorWebViewBackCallbackDisabledWhenCannotGoBack failed with the fix. Inspection of the truncated Helix log shows the failure is not an assertion failure inside the new test — every Blazor device test in the batch (BasicRazorComponentClick, BlazorWebViewWithoutDispatchFailsToGetScopedServices, RequestsCanBe…ForDifferentHosts, RequestsCanBeInterceptedAndCaseInsensitiveHeadersRead, etc.) hits the same System.Exception: Waited 30000ms but couldn't get window.Blazor to be non-null *and* have window.__BlazorStarted to be true at WebViewHelpers.WaitForWebViewReady. This is a CI/environment flake on the Helix device-test runner (the WebView never completed Blazor startup within 30s on this run) and is unrelated to the production diff. The without-fix run also failed (as expected), so the gate booked the result as FAILED.
Concerns with the PR's approach (used to seed alternative candidates)
Platform.CurrentActivity≠ this WebView's activity. Using the staticCurrentActivitycan wire the callback to the wrong activity in multi-window / multi-activity scenarios. The Activity attached to the WebView'sContextis the correct owner.HandleOnBackPresseddisabling itself is a one-shot escape hatch, not a delegation. SettingEnabled = falseinside the handler does not re-dispatch the current back press to the next callback in the LIFO dispatcher — it only affects future presses. So if the WebView's callback fires butHasWindowFocusorIsAttachedToWindowis false, the current press is silently swallowed. The comment in the code asserts otherwise, butOnBackPressedDispatcherdoes not re-dispatch within a single invocation.- Removing
OnKeyDownfromBlazorAndroidWebViewmay affect pre-Q hardware-back behavior in WebViews that have iframes/redirects whereWebView.canGoBack()returns true but the dispatcher chain has already advanced. DoUpdateVisitedHistoryruns forpushStatebut not always immediately forhistory.go(-1)ordering edge cases. Combined withOnPageFinishedit should be sufficient, but aWebChromeClient-level hook would be more robust.IBackNavigationStateaccessibility change is unrelated to this fix; it should be split out or removed.
These concerns drove the three alternative candidates in try-fix-1, try-fix-2, try-fix-3.
🔧 Fix — Analysis & Comparison
Try-Fix Aggregate — PR #35538
Summary
Generated three meaningfully different alternative fix candidates for issue #35397, driven by the maui-expert-reviewer agent and seeded by structural concerns identified in pre-flight.
Loop termination reason: the candidate space is exhausted across the two orthogonal design axes — which back API to use (IOnBackInvokedCallback vs AndroidX OnBackPressedCallback) × what to toggle (registration vs Enabled). Further variations would be trivial.
Testing constraint: the Helix device-test runner is not available in this sub-agent environment, so per-candidate "test" steps are static reasoning rather than executed runs. The PR-level gate had already been pre-completed and showed environmental flake (every Blazor test, not just the new one, timed out at WebViewHelpers.WaitForWebViewReady's 30s wait for window.Blazor). This is independent of the production diff.
Candidate matrix
| # | Approach | Back API | Toggle | Ownership | Pre-Q OnKeyDown |
|---|---|---|---|---|---|
| try-fix-1 | A | IOnBackInvokedCallback (33+) + OnKeyDown (≤32) |
Registration | Handler | ✅ kept |
| try-fix-2 | B | AndroidX OnBackPressedCallback (unified) |
Enabled |
Handler (+ view events) | ✅ kept |
| try-fix-3 | C | AndroidX OnBackPressedCallback (unified) |
Registration | View | ✅ kept |
| PR (current) | — | AndroidX OnBackPressedCallback (unified) |
Enabled |
Handler | ❌ removed |
Ranking (recommended → least)
A > C > B
-
Candidate A (try-fix-1) — recommended. Strongest fix: Android 16 suppresses the predictive back-to-home animation specifically because a callback is registered; toggling registration removes that signal entirely. Smallest blast radius (closest to git-history-proven behavior). Multi-window correctness for free via view-anchored
FindOnBackInvokedDispatcher(). PreservesOnKeyDownfor pre-Q hardware back. One open detail before merge: theFindOnBackInvokedDispatcherAPI matrix on API 33 vs 34+ — fallback toActivity.OnBackInvokedDispatcherfrom the view's ownContext. -
Candidate C (try-fix-3) — second. Architecturally cleanest (view-owned callback lifecycle is the canonical Android pattern). Also fixes a Shell-tab-switch case the PR doesn't handle. Lower confidence to land in a regression-fix PR due to larger code-review surface and higher risk of touching the test paths that timed out in the gate run.
-
Candidate B (try-fix-2) — acceptable. Smallest delta from the PR while correcting its two design bugs (wrong activity, broken
Enabled=falseself-disable). SameEnabled-toggle architecture as the PR, which means it inherits the same residual risk thatEnabled = falsemay not unblock the predictive animation on every Android 16 OEM ROM.
Concerns about the PR's current fix (recap)
All three candidates address one or more of these:
Microsoft.Maui.ApplicationModel.Platform.CurrentActivityis the wrong activity in multi-window / multi-activity. The Activity attached to the WebView's ownContextis correct.- Setting
Enabled = falseinsideHandleOnBackPresseddoes not re-dispatch the current back press to the next LIFO callback. The code comment that asserts otherwise is incorrect; the current press is silently swallowed. - Removing
BlazorAndroidWebView.OnKeyDownmay regress pre-Q hardware-back behavior in WebViews with iframe history. - The
IBackNavigationStateaccessibility change is unrelated noise that should be split out of this PR.
Per-candidate artifacts
try-fix-1/content.md— Candidate Atry-fix-2/content.md— Candidate Btry-fix-3/content.md— Candidate C
Recommendation to PR author
Adopt Candidate A (try-fix-1). Restore BlazorAndroidWebView.OnKeyDown, revert to IOnBackInvokedCallback on API 33+ but register/unregister dynamically based on CanGoBack() && IsAttachedToWindow, anchor the dispatcher lookup to the WebView (pv.FindOnBackInvokedDispatcher() with an Activity.OnBackInvokedDispatcher fallback on API 33), and drop the unrelated IBackNavigationState accessibility change from this PR.
📋 Report — Final Recommendation
Comparative Report — PR #35538
Issue and PR
- Issue [Android] BlazorWebView predictive back callback blocks Android back-to-home animation #35397 —
[Android] BlazorWebView predictive back callback blocks Android back-to-home animation(regression in 10.0.11). - PR [Android] Fix for BlazorWebView predictive back callback blocks Android back-to-home animation #35538 head
391470fe(baseinflight/current). - Root cause:
BlazorWebViewHandler.Android.csunconditionally registers anIOnBackInvokedCallbackon API 33+ inConnectHandler. With a callback always registered, Android 16 suppresses the back-to-home animation even when the WebView has no back history.
Candidate inventory
| Candidate | Back API | What toggles | Activity owner | Pre-Q OnKeyDown |
Diff size |
|---|---|---|---|---|---|
pr |
AndroidX OnBackPressedCallback (unified) |
Enabled |
Platform.CurrentActivity ❌ |
❌ removed | -195/+83 |
pr-plus-reviewer |
AndroidX OnBackPressedCallback (unified) |
Enabled (continuously updated) |
view-anchored ✅ | ✅ restored | similar to pr + view events |
try-fix-1 |
IOnBackInvokedCallback (33+) + OnKeyDown (≤32) |
Registration | view-anchored ✅ | ✅ kept | smallest behavioral delta from 10.0.10 |
try-fix-2 |
AndroidX OnBackPressedCallback |
Enabled (continuously updated) |
view-anchored ✅ | ✅ restored | same as pr-plus-reviewer |
try-fix-3 |
AndroidX OnBackPressedCallback (View-owned) |
Registration | view-anchored ✅ | ✅ kept | largest — moves ownership to View |
Note: pr-plus-reviewer and try-fix-2 are conceptually identical (Enabled-toggle architecture with all PR design bugs fixed). They are presented separately to satisfy the schema but are scored together below.
Gate status (shared across all candidates)
Pre-completed gate: ❌ FAILED, but the failure is environmental — every Blazor device test in the Helix batch timed out at WebViewHelpers.WaitForWebViewReady's 30 s wait for window.Blazor to become non-null. The without-fix run also failed (as expected for a presence-check gate). Per task instruction the gate is not re-run. Because the failure is environmental and shared across every Blazor test in the batch, no candidate is differentially penalized. None of the candidates "passed regression tests" and none "failed regression tests" in the differential sense — the regression test never executed cleanly on either side of the comparison.
Scoring axes
- Predictive-animation guarantee (Android 16): "Registration toggle" > "
Enabledtoggle". With no callback registered, AOSP contract plays the back-to-home animation; withEnabled = falseon a registered callback, behavior depends on AndroidX 1.8+ semantics and OEM ROM compliance (this is the exact behavior the regression originated from). - Activity-owner correctness (multi-window / multi-activity): view-anchored >
Platform.CurrentActivity. - Self-disable correctness:
Enabledcontinuously updated from focus/attach/navigation >Enabled = falseinsideHandleOnBackPressed(current press is silently swallowed; the next press is the first to honor the new state). - Pre-Q hardware-back coverage:
OnKeyDownpreserved > removed. - Blast radius: smaller diff with closer affinity to last-known-good (10.0.10) > larger architectural rework.
- Test correctness: asserting the new code path's invariant > asserting a property of
Android.Webkit.WebView.
Per-candidate scoring
| Anim guarantee | Activity owner | Self-disable | Pre-Q hw back | Blast radius | Test quality | |
|---|---|---|---|---|---|---|
pr |
⚠ depends on Enabled = false |
❌ Platform.CurrentActivity |
❌ silently swallows current press | ❌ removed | ✅ moderate | ⚠ thin |
pr-plus-reviewer |
⚠ depends on Enabled = false |
✅ view-anchored | ✅ continuously honest | ✅ restored | ✅ moderate | ⚠ thin |
try-fix-1 |
✅ registration toggle | ✅ view-anchored | ✅ N/A (registration) | ✅ kept | ✅ closest to 10.0.10 | ⚠ thin |
try-fix-2 |
⚠ depends on Enabled = false |
✅ view-anchored | ✅ continuously honest | ✅ restored | ✅ moderate | ⚠ thin |
try-fix-3 |
✅ registration toggle | ✅ view-anchored | ✅ N/A (registration) | ✅ kept | ⚠ largest | ⚠ thin |
Ranking
try-fix-1 > try-fix-3 > pr-plus-reviewer ≈ try-fix-2 > pr
try-fix-1(Candidate A) ranks first: it is the only candidate that gives the AOSP-contract animation guarantee (registration toggle) and has the smallest behavioral delta from the last-known-good 10.0.10 code (keptIOnBackInvokedCallbackon 33+, keptOnKeyDownon ≤32, fixed the bug by toggling registration). One implementation refinement is required before merge — handlingOnBackInvokedDispatcherresolution on API 33 vs 34+ (use the view's owning activity'sOnBackInvokedDispatcher, notPlatform.CurrentActivity).try-fix-3(Candidate C) ranks second: same animation guarantee but with a larger architectural rework (ownership moves intoBlazorAndroidWebView). Lower confidence to land late in a release cycle.pr-plus-reviewerandtry-fix-2(Candidate B) tie for third: they correctly fix the activity-owner and self-disable bugs and restoreOnKeyDown, but they still rely onEnabled = falseto release the gesture — the residual Android 16 OEM-ROM risk remains.prranks last: it ships the activity-owner bug, the broken self-disable comment claim, removes pre-QOnKeyDowndefense, and carries an unrelatedIBackNavigationStateaccessibility no-op.
Winner
try-fix-1. It addresses the root cause directly (no callback registered ⇒ AOSP guarantees the back-to-home animation), keeps the codebase closest to the last shipping version, preserves all defense-in-depth paths the PR removed, and avoids both design bugs the reviewer identified in pr. The required implementation refinement (resolve OnBackInvokedDispatcher from the view's owning activity rather than Platform.CurrentActivity) is included in the winner manifest's candidateDiff.
Concerns the winner does not address
- Test coverage thinness. The PR's replacement test only asserts
platformWebView.CanGoBack() == falseafter the initial load — a property ofAndroid.Webkit.WebView, not of the new BlazorWebView code path. Whichever candidate ships, the test should be strengthened to actually exercise the callback-registration invariant. Out of scope for a regression fix; track as follow-up. - Environmental Helix flake is unrelated to any candidate and must be diagnosed separately.
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May 20, 2026
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Upon further investigation, the PR's original fix (OnBackPressedCallback + Enabled toggling) is the correct and sufficient approach for this issue. The gate failure shown in the summary was related to test infrastructure/timing and not to code correctness. The fix correctly restores the predictive back to home animation. This approach is also intentionally consistent with the already merged PR #35223, which used the same OnBackPressedCallback + Enabled pattern to fix the same animation issue at the activity level for standard MAUI navigation. try-fix-1 was also evaluated. It works after adapting for .NET Android binding differences (OnBackInvokedDispatcher.PriorityDefault is not exposed as a named constant and was replaced with const int = 0, and Android.App.Activity requires the global:: prefix). However, it introduces additional complexity without necessity, since the PR's simpler approach already passes the gate and resolves the issue correctly. |
This was referenced May 21, 2026
kubaflo
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May 21, 2026
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Looks like this PR introduced a regression: #35573 |
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PureWeen
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Jun 2, 2026
…id back-to-home animation (#35538) > [!NOTE] > Are you waiting for the changes in this PR to be merged? > It would be very helpful if you could [test the resulting artifacts](https://github.com/dotnet/maui/wiki/Testing-PR-Builds) from this PR and let us know in a comment if this change resolves your issue. Thank you! ### Issue details The predictive back-to-home animation on Android does not play when a `BlazorWebView` is present on screen. On Android 16, swiping back from the root page skips the animation instead of showing the smooth system transition. ### Root Cause The issue occurs because BlazorWebViewHandler registers an IOnBackInvokedCallback unconditionally on API 33+, regardless of whether the WebView contains back navigation history. As a result, the callback remains continuously active, preventing the Android system from recognizing when no further back navigation is available, which in turn blocks the predictive back-to-home animation from being triggered. ### Description of Change The fix involves replacing the legacy IOnBackInvokedCallback and AndroidLifecycle.OnBackPressed handling with a unified AndroidX.Activity.OnBackPressedCallback, where the Enabled property serves as the single source of truth for back navigation handling. When the WebView has no navigation history, the callback is disabled (Enabled = false), allowing the Android system to process the back gesture normally and display the predictive back-to-home animation. To ensure the callback state remains accurate, UpdateBackNavigationState() is invoked after every navigation event from both OnPageFinished and DoUpdateVisitedHistory, covering standard page navigations as well as Blazor SPA route changes. Additionally, a fallback mechanism in HandleOnBackPressed() sets Enabled = false when the WebView is detached or not focused, ensuring the back gesture is correctly delegated to the next available system handler. ### Why Tests were not added: **Regarding the test case:** This issue is specific to Android 16 (API 36), while the current automated device test coverage does not reliably reproduce this exact platform behavior in CI. Because of that limitation, a deterministic automated repro test could not be added at this time. Validation was performed through manual Android 16 scenario testing focused on root-page predictive back and navigated-page back handling. Tested the behavior in the following platforms. - [x] Android - [ ] Mac - [ ] iOS - [ ] Windows ### Issues Fixed Fixes #35397 ### Output | Before Issue Fix | After Issue Fix | |----------|----------| | <video width="270" height="600" src="https://github.com/user-attachments/assets/c817cac7-2b93-4d01-9b1f-dc83651f7485"> | <video width="270" height="600" src="https://github.com/user-attachments/assets/5ce098e0-a51a-4abf-8b50-e9130f763db0"> |
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Note
Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!
Issue details
The predictive back-to-home animation on Android does not play when a
BlazorWebViewis present on screen. On Android 16, swiping back from the root page skips the animation instead of showing the smooth system transition.Root Cause
The issue occurs because BlazorWebViewHandler registers an IOnBackInvokedCallback unconditionally on API 33+, regardless of whether the WebView contains back navigation history. As a result, the callback remains continuously active, preventing the Android system from recognizing when no further back navigation is available, which in turn blocks the predictive back-to-home animation from being triggered.
Description of Change
The fix involves replacing the legacy IOnBackInvokedCallback and AndroidLifecycle.OnBackPressed handling with a unified AndroidX.Activity.OnBackPressedCallback, where the Enabled property serves as the single source of truth for back navigation handling. When the WebView has no navigation history, the callback is disabled (Enabled = false), allowing the Android system to process the back gesture normally and display the predictive back-to-home animation.
To ensure the callback state remains accurate, UpdateBackNavigationState() is invoked after every navigation event from both OnPageFinished and DoUpdateVisitedHistory, covering standard page navigations as well as Blazor SPA route changes. Additionally, a fallback mechanism in HandleOnBackPressed() sets Enabled = false when the WebView is detached or not focused, ensuring the back gesture is correctly delegated to the next available system handler.
Why Tests were not added:
Regarding the test case: This issue is specific to Android 16 (API 36), while the current automated device test coverage does not reliably reproduce this exact platform behavior in CI. Because of that limitation, a deterministic automated repro test could not be added at this time. Validation was performed through manual Android 16 scenario testing focused on root-page predictive back and navigated-page back handling.
Tested the behavior in the following platforms.
Issues Fixed
Fixes #35397
Output
35397-BeforeFix.BlazorWebView.mov
35397-AfterFix.BlazorWebView.mov