Fix for BlazorWebView Back Navigation Issues on Android 13+ After Predictive Back Gesture Changes by SuthiYuvaraj · Pull Request #33213 · dotnet/maui

SuthiYuvaraj · 2025-12-18T13:54:58Z

Issue Description

BlazorWebView back navigation stopped working in .NET 10 on Android. When the user presses the back button while viewing a BlazorWebView with navigable history, the entire page is popped instead of navigating back within the WebView content

RootCause

The AndroidLifecycle.OnBackPressed lifecycle event system introduced for Android 13+ predictive back gesture support intercepts back navigation. Since BlazorWebView doesn't register a handler to check WebView.CanGoBack(), the system pops the entire page instead of allowing the WebView to navigate its internal history first, breaking the back navigation behavior that worked in .NET 9.

Description of Change

PR #32461 introduced distributed back navigation handling for Android 13+ predictive back gesture support. This PR extends that implementation to include BlazorWebView

BlazorWebViewHandler.Android.cs:

Added an AndroidLifecycle.OnBackPressed handler in ConnectHandler. The handler checks WebView.CanGoBack() to determine whether the BlazorWebView maintains internal navigation history. If history exists, it calls WebView.GoBack() and returns true, ensuring the user navigates backwards within the WebView instead of closing the page. If no internal history exists, it returns false, allowing the standard MAUI navigation stack to handle the back action.

LifecycleEventService.cs:

Added RemoveEvent<TDelegate> method to properly cleanup lifecycle event handlers and prevent memory leaks when handlers are disconnected.

Issues Fixed

Fixes #32767

Tested the behaviour on the following platforms

Android
Windows
iOS
Mac

Output Screenshot

Before Issue Fix	After Issue Fix
Screen.Recording.2025-12-18.at.7.21.48.PM.mov	Screen.Recording.2025-12-18.at.7.13.08.PM.mov

Copilot

Pull request overview

This PR fixes BlazorWebView back navigation on Android 13+ by implementing an OnBackPressed lifecycle event handler that checks for WebView navigation history before allowing page navigation. The fix extends the predictive back gesture support introduced in PR #32461 to include BlazorWebView components, and adds a cleanup mechanism for lifecycle event handlers to prevent memory leaks.

Key Changes

Adds OnBackPressed handler registration in BlazorWebViewHandler.ConnectHandler that checks WebView.CanGoBack() before allowing page pop
Implements RemoveEvent method in LifecycleEventService to support proper handler cleanup in DisconnectHandler
Updates public API surface to track the new ConnectHandler override

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 7 comments.

File	Description
src/Core/src/LifecycleEvents/LifecycleEventService.cs	Adds internal RemoveEvent method to enable lifecycle event handler cleanup
src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs	Implements ConnectHandler/DisconnectHandler overrides to register/unregister OnBackPressed handler for WebView back navigation
src/BlazorWebView/src/Maui/PublicAPI/net-android/PublicAPI.Unshipped.txt	Tracks new ConnectHandler override as public API surface change

src/Core/src/LifecycleEvents/LifecycleEventService.cs

src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs

src/Core/src/LifecycleEvents/LifecycleEventService.cs

Copilot · 2025-12-18T15:39:05Z

src/BlazorWebView/src/Maui/Android/BlazorWebViewHandler.Android.cs

+				var lifecycleService = MauiContext.Services.GetService<ILifecycleEventService>();
+				if (lifecycleService is LifecycleEventService concreteService)
+				{
+					concreteService.RemoveEvent(nameof(AndroidLifecycle.OnBackPressed), _onBackPressedHandler);
+					_onBackPressedHandler = null;
+				}


The same cast pattern (ILifecycleEventService to LifecycleEventService) is repeated in both ConnectHandler and DisconnectHandler. Consider extracting this to a helper method or property to reduce code duplication and make the intent clearer. For example, a private method like TryGetLifecycleEventService() that returns the concrete service or null.

StephaneDelcroix

✅ APPROVE

Summary: PR correctly fixes BlazorWebView back navigation on Android 13+ by registering an OnBackPressed lifecycle event handler.

What the PR Does

Adds OnBackPressed handler in ConnectHandler that checks CanGoBack() before navigating
Handles multiple BlazorWebView instances with visibility/focus checks (IsAttachedToWindow, HasWindowFocus)
Uses WeakReference to prevent memory leaks
Adds RemoveEvent to LifecycleEventService for proper cleanup
Cleans up handler in DisconnectHandler to prevent leaks

Tests Added

I've added Device Tests to verify the fix:

BlazorWebViewRegistersOnBackPressedHandler - Verifies handler is registered when BlazorWebView connects
BlazorWebViewCleansUpOnBackPressedHandlerOnDisconnect - Verifies cleanup on disconnect

Location: src/BlazorWebView/tests/DeviceTests/Elements/BlazorWebViewTests.BackNavigation.cs

Alternative Approaches Considered

Override OnKeyDown: Won't work with Android 13+ predictive back gestures
Use AndroidX OnBackPressedDispatcher directly: Bypasses MAUI's existing architecture
PR's approach is optimal - integrates with MAUI's lifecycle event system

Minor Notes (Non-blocking)

RemoveEvent kept internal (acceptable, would require API review for public)
Thread-safety matches existing pattern in LifecycleEventService

Confidence: High - PR follows MAUI's established patterns and addresses all edge cases.

rmarinho · 2026-01-11T11:06:17Z

/azp run maui-pr-uitests

azure-pipelines · 2026-01-11T11:06:28Z

Azure Pipelines successfully started running 1 pipeline(s).

rmarinho · 2026-01-11T11:06:39Z

/azp run maui-pr-devicetests

azure-pipelines · 2026-01-11T11:06:52Z

Azure Pipelines successfully started running 1 pipeline(s).

erva0008 · 2026-01-12T11:53:32Z

@StephaneDelcroix
Hello Stephane, I tried your PR and found a possible problem.
Can you have a look at my video from today at:
#32767 (comment)

erva0008 · 2026-01-15T15:29:40Z

@SuthiYuvaraj Did you see my comment/videos in the linked issue at
#32767 (comment)

PureWeen

#33213 (comment)

SubhikshaSf4851 · 2026-01-20T13:50:08Z

@PureWeen The issue where the back button immediately exited the app instead of navigating within the BlazorWebView is now fixed.

erva0008 · 2026-01-20T15:08:44Z

I have tested the artifacts locally on my computer from @SubhikshaSf4851 's fix.
I can confirm that it now works for me.
Both "swiping" backwards and the button press navigates correctly "inside" the Blazor application until it's in the root, and then finally closing the app (like expected)⭐

PureWeen · 2026-01-22T00:15:42Z

/rebase

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Tests verify that BlazorWebViewHandler on Android: 1. Registers OnBackPressed lifecycle event handler in ConnectHandler 2. Properly cleans up the handler in DisconnectHandler Related to: dotnet#32767

…dictive Back Gesture Changes (#33213)  ### Issue Description BlazorWebView back navigation stopped working in .NET 10 on Android. When the user presses the back button while viewing a BlazorWebView with navigable history, the entire page is popped instead of navigating back within the WebView content ### RootCause The AndroidLifecycle.OnBackPressed lifecycle event system introduced for Android 13+ predictive back gesture support intercepts back navigation. Since BlazorWebView doesn't register a handler to check WebView.CanGoBack(), the system pops the entire page instead of allowing the WebView to navigate its internal history first, breaking the back navigation behavior that worked in .NET 9. ### Description of Change PR #32461 introduced distributed back navigation handling for Android 13+ predictive back gesture support. This PR extends that implementation to include BlazorWebView **BlazorWebViewHandler.Android.cs:** Added an `AndroidLifecycle.OnBackPressed` handler in ConnectHandler. The handler checks `WebView.CanGoBack()` to determine whether the BlazorWebView maintains internal navigation history. If history exists, it calls `WebView.GoBack()` and returns true, ensuring the user navigates backwards within the WebView instead of closing the page. If no internal history exists, it returns false, allowing the standard MAUI navigation stack to handle the back action. **LifecycleEventService.cs**: Added `RemoveEvent<TDelegate>` method to properly cleanup lifecycle event handlers and prevent memory leaks when handlers are disconnected. ### Issues Fixed Fixes #32767 ### Tested the behaviour on the following platforms - [x] Android - [ ] Windows - [ ] iOS - [ ] Mac ### Output Screenshot Before Issue Fix | After Issue Fix | |----------|----------| |<video width="300" height="150" alt="Before Fix" src="https://github.com/user-attachments/assets/0d6550f8-115a-4893-bb0c-ee24bff38378">|<video width="300" height="150" alt="After Fix" src="https://github.com/user-attachments/assets/49bf38a5-f7be-4790-8fbb-b29ab96b1ed3">| --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Co-authored-by: Stephane Delcroix <stephane@delcroix.org> Co-authored-by: Subhiksha Chandrasekaran <subhiksha.c@syncfusion.com>

@SuthiYuvaraj

.NET MAUI inflight/candidate introduces significant improvements across all platforms with focus on quality, performance, and developer experience. This release includes 20 commits with various improvements, bug fixes, and enhancements. ## Blazor - Fix for BlazorWebView Back Navigation Issues on Android 13+ After Predictive Back Gesture Changes by @SuthiYuvaraj in #33213 <details> <summary>🔧 Fixes</summary> - [Back navigation different between .net 9 and .net 10 blazor hybrid](#32767) </details> ## CollectionView - [Android] Fix for CollectionView.EmptyView does not remeasure its height when the parent layout changes dynamically, causing incorrect sizing. by @BagavathiPerumal in #33559 <details> <summary>🔧 Fixes</summary> - [`CollectionView.EmptyView` does not remeasure its height when the parent layout changes dynamically, causing incorrect sizing.](#33324) </details> - [Android] Fixed CollectionView reordering last item by @vitalii-vov in #17825 <details> <summary>🔧 Fixes</summary> - [Android app crashes when dragging into CollectionView](#17823) </details> ## DateTimePicker - [iOS] Fix VoiceOver focus not shifting to Picker/DatePicker/TimePicker popups by @kubaflo in #33152 <details> <summary>🔧 Fixes</summary> - [Voiceover does not automatically shift focus to the "Category" popup when it opens.: A11y_Developer balance version .NET 10_Project_ScreenReader](#30746) </details> ## Dialogalert - [iOS 26] Fix DisplayPromptAsync maxLength not enforced due to new multi-range delegate by @Shalini-Ashokan in #33616 <details> <summary>🔧 Fixes</summary> - [[iOS 26.1] DisplayPromptAsync ignores maxLength and does not respect RTL FlowDirection](#33549) </details> ## Flyout - [iOS] Shell: Account for SafeArea when positioning flyout footer by @kubaflo in #32891 <details> <summary>🔧 Fixes</summary> - [[IOS] Footer not displaying in iOS when StackOrientation.Horizontal is set on FlyoutFooter](#26395) </details> ## Fonts - Hide obsolete FontSize values from IDE autocomplete by @noiseonwires in #33694 ## Gestures - Android pan fixes by @BurningLights in #21547 <details> <summary>🔧 Fixes</summary> - [Flickering occurs while updating the width of ContentView through PanGestureRecognizer.](#20772) </details> ## Navigation - Shell: Add duplicate route validation for sibling elements by @SubhikshaSf4851 in #32296 <details> <summary>🔧 Fixes</summary> - [OnNavigatedTo is not called when navigating from a specific page](#14000) </details> ## Picker - Improved Unfocus support for Picker on Mac Catalyst by @kubaflo in #33127 <details> <summary>🔧 Fixes</summary> - [When using voiceover unable to access expanded list of project combo box: A11y_.NET maui_user can creat a tak_Screen reader](#30897) - [Task and Project controls are not accessible with keyboard:A11y_.NET maui_User can create a new task_Keyboard](#30891) </details> ## SafeArea - [iOS] SafeArea: Return Empty for non-ISafeAreaView views (opt-in model) by @praveenkumarkarunanithi in #33526 <details> <summary>🔧 Fixes</summary> - [[iOS] SafeArea is not applied when a ContentPage uses a ControlTemplate](#33458) </details> ## Shell - [iOS] Fix ObjectDisposedException in TraitCollectionDidChange on window disposal by @jeremy-visionaid in #33353 <details> <summary>🔧 Fixes</summary> - [Intermittent crash on exit on MacCatalyst - ObjectDisposedException](#33352) </details> - [Issue-Resolver] Explicit fallback for BackButtonBehavior lookup by @kubaflo in #33204 <details> <summary>🔧 Fixes</summary> - [Setting BackButtonBehavior to not visible or not enabled does not work](#28570) - [BackButtonBehavior not bound](#33139) </details> ## Templates - [Templates] Remove redundant SemanticProperties.Description attribute by @kubaflo in #33621 <details> <summary>🔧 Fixes</summary> - [Task and Project controls are not accessible with keyboard:A11y_.NET maui_User can create a new task_Keyboard](#30891) - [Unable to select "Tags" when Voiceover is turned on.: A11y_Developer balance version .NET 10_Project_ScreenReader](#30749) </details> ## Theme - [Windows] Fix runtime theme update for controls and TitleBar by @Tamilarasan-Paranthaman in #31714 <details> <summary>🔧 Fixes</summary> - [[Windows][MacOS?] Change title bar color when switching light/dark theme at runtime](#12507) - [OS system components ignore app theme](#22058) - [[Mac Catalyst][Windows] TitleBar not reacting on UserAppTheme changes](#30518) - [In dark theme "Back" and "hamburger" button icon color contrast with background color is less than 3:1: A11y_.NET maui_User can get all the insights of Dashboard_Non text Contrast](#30807) - [`Switch` is invisible on `PointOver` when theme has changed](#31819) </details> ## Theming - [XSG] Fix Style Setters referencing source-generated bindable properties by @simonrozsival in #33562 ## Titlebar - [Windows] Fix TitleBar.IsVisible = false the caption buttons become unresponsive by @devanathan-vaithiyanathan in #33256 <details> <summary>🔧 Fixes</summary> - [When TitleBar.IsVisible = false the caption buttons become unresponsive on Windows](#33171) </details> ## WebView - Fix WebView JavaScript string escaping for backslashes and quotes by @StephaneDelcroix in #33726 ## Xaml - [XSG] Fix NaN value in XAML generating invalid code by @StephaneDelcroix in #33533 <details> <summary>🔧 Fixes</summary> - [[XSG] NaN value in XAML generates invalid code](#33532) </details> <details> <summary>📦 Other (1)</summary> - Remove InternalsVisibleTo attributes for .NET MAUI Community Toolkit by @jfversluis via @Copilot in #33442 </details> **Full Changelog**: main...inflight/candidate

dotnet-policy-service bot added the partner/syncfusion Issues / PR's with Syncfusion collaboration label Dec 18, 2025

vishnumenon2684 added the community ✨ Community Contribution label Dec 18, 2025

sheiksyedm added area-blazor Blazor Hybrid / Desktop, BlazorWebView platform/android labels Dec 18, 2025

SuthiYuvaraj changed the title ~~Fix for Back navigation different between .net 9 and .net 10 blazor hybrid~~ Fix for BlazorWebView Back Navigation Issues on Android 13+ After Predictive Back Gesture Changes Dec 18, 2025

sheiksyedm marked this pull request as ready for review December 18, 2025 15:27

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Back navigation different between .net 9 and .net 10 blazor hybrid #32767

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build-analysis bot mentioned this pull request Dec 19, 2025

System.TimeoutException #33245

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PureWeen modified the milestones: .NET 10.0 SR3, .NET 10.0 SR4 Jan 21, 2026

SuthiYuvaraj and others added 7 commits January 22, 2026 00:16

fix-lifecycleEvent

356a931

Added RemoveEvent

1401aa7

remove publicAPI

2e08b43

Apply suggestion from @Copilot

90917be

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Update BlazorWebViewHandler.Android.cs

14d7d07

Add Device Tests for BlazorWebView OnBackPressed handler registration

778ac31

Tests verify that BlazorWebViewHandler on Android: 1. Registers OnBackPressed lifecycle event handler in ConnectHandler 2. Properly cleans up the handler in DisconnectHandler Related to: dotnet#32767

Fix for back button navigation

4714458

github-actions bot force-pushed the fix-32767 branch from 5ade657 to 4714458 Compare January 22, 2026 00:16

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PureWeen changed the base branch from main to inflight/current January 22, 2026 00:27

PureWeen merged commit b0fec72 into dotnet:inflight/current Jan 22, 2026
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PureWeen mentioned this pull request Feb 3, 2026

February 2nd, Candidate #33779

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Issue Description

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Description of Change

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Tested the behaviour on the following platforms

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✅ APPROVE

What the PR Does

Tests Added

Alternative Approaches Considered

Minor Notes (Non-blocking)

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