[Android] Controls Disappear When WebView is Used with Hardware Acceleration Disabled

[praveenkumarkarunanithi]

Root Cause

When android:hardwareAccelerated="false" is set in Android applications, standard UI elements switch to software rendering, but WebView may continue using hardware optimization. This inconsistency causes WebView to occasionally render above other UI elements, disrupting the expected visual hierarchy.

Description of Change

The solution involves setting the WebView to use the software rendering pipeline by applying SetLayerType(Android.Views.LayerType.Software, null) when hardware acceleration is disabled. This ensures that WebView aligns with the rendering behavior of other UI elements, maintaining correct layering and preventing any UI components from being obscured.

Issues Fixed

Fixes #28902

Tested the behaviour in the following platforms

• Android
• Windows
• iOS
• Mac

Note

This issue is specific to Android, as hardware acceleration settings are not applicable on other platforms.

Screenshots

Before Issue Fix	After Issue Fix

[dotnet-policy-service]

Hey there @@praveenkumarkarunanithi! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jsuarezruiz]

/azp run MAUI-UITests-public

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jsuarezruiz]

/azp run MAUI-UITests-public

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jsuarezruiz]

/azp run MAUI-UITests-public

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Copilot]

Pull Request Overview

This PR addresses an Android-specific rendering issue where WebView appears above other UI controls when hardware acceleration is disabled. The changes include modifying the WebViewHandler on Android to enforce software rendering and adding test cases in both Shared.Tests and HostApp to validate the fix.

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
src/Core/src/Handlers/WebView/WebViewHandler.Android.cs	Updates WebView creation to call SetLayerType() for software rendering when hardware acceleration is disabled.
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28798.cs	Adds a test case to verify that controls remain visible under the issue conditions on Android.
src/Controls/tests/TestCases.HostApp/Issues/Issue28798.cs	Provides a sample page for manual testing of the WebView rendering fix.

Comments suppressed due to low confidence (2)

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28798.cs:8

• [nitpick] The test case class is named 'Issue28798', but the PR metadata references issue #28902. Consider aligning the identifiers for clarity.

internal class Issue28798 : _IssuesUITest

src/Controls/tests/TestCases.HostApp/Issues/Issue28798.cs:1

• [nitpick] The file name uses 'Issue28798' whereas the PR metadata mentions issue #28902. It would be clearer if the identifiers were consistent.

namespace Maui.Controls.Sample.Issues;

[mattleibow]

AI says this will ot work, but so far your screenshot says it does.

From AI:

Doesn’t fix layout compositing problems between WebView and other views, because WebView uses a separate surface or texture layer, which is not affected by SetLayerType.

WebView itself ignores SetLayerType(), as it uses a separate SurfaceView or TextureView internally.

So since this can't make it worse, it is OK.

But Android may be wrong:

https://github.com/aosp-mirror/platform_frameworks_base/blob/1cdfff555f4a21f71ccc978290e2e212e2f8b168/core/java/android/webkit/WebView.java#L3045-L3049

It looks like it is doing somehting with this method:

    @Override
    public void setLayerType(int layerType, Paint paint) {
        super.setLayerType(layerType, paint);
        mProvider.getViewDelegate().setLayerType(layerType, paint);
    }

[mattleibow]

/rebase

[mattleibow]

I guess it may work since CI is accelerated... So technically the test is not doing much.

@praveenkumarkarunanithi did you verify this works when using the android:hardwareAccelerated="false" on the activity or in the manifest?

[mattleibow]

I tested it here and it works. AI is wrong. So sad.

[jsuarezruiz]

(Optional) Could be nice to log this:

 System.Diagnostics.Debug.WriteLine(
                "WebView set to software rendering due to disabled hardware acceleration");

[jsuarezruiz]

The activities can have different hardware acceleration settings that override the app-level setting, but in out case, I think checking at app level is enough.