[Android] Fix the Setting Content of ContentView through style would crash on parent change

[Ahamed-Ali]

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!

Root Cause of the issue

• The specific child view retains a reference to its old parent when dynamically added because it is defined as a static resource in style. This leads to an IllegalStateException on Android when the view is added to a new parent without being removed from the old one.

Description of Change

• Before adding the child view to the new parent, ensure that it is detached from any existing parent to prevent the IllegalStateException.

Issues Fixed

Fixes #11812

Windows Fix PR : #30047

Tested the behaviour in the following platforms

• Android
• Windows
• iOS
• Mac

Screenshot

Before Issue Fix	After Issue Fix
ExceptionOfContentView.mov	FixedContentViewissue.mov

[jsuarezruiz]

/azp run MAUI-UITests-public

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Copilot]

Pull Request Overview

This PR prevents IllegalStateException crashes on Android (and aligns iOS behavior) when setting a ContentView’s content via a style by detaching any existing parent before re-adding the view.

• Detach and remove old platform views before adding new ones in both ContentViewHandler and BorderHandler for Android and iOS
• Introduce a UI test in Shared.Tests and HostApp to reproduce and guard against regressions for Issue #11812

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Core/src/Handlers/ContentView/ContentViewHandler.iOS.cs	Call RemoveFromSuperview before AddSubview
src/Core/src/Handlers/ContentView/ContentViewHandler.Android.cs	Call RemoveFromParent before AddView
src/Core/src/Handlers/Border/BorderHandler.iOS.cs	Call RemoveFromSuperview before adding scroll or content
src/Core/src/Handlers/Border/BorderHandler.Android.cs	Call RemoveFromParent before AddView
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue11812.cs	Add a UI test tapping the content-change button
src/Controls/tests/TestCases.HostApp/Issues/Issue11812.cs	Host app scenario wiring up the styled ContentView change button

Comments suppressed due to low confidence (3)

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue11812.cs:1

• The conditional compilation symbol TEST_FAILS_ON_WINDOWS may prevent this test from running on Android/iOS. Consider using a platform-specific symbol (e.g., WINDOWS) or inverting the condition to exclude only Windows builds, ensuring the test executes on supported platforms.

#if TEST_FAILS_ON_WINDOWS // test fails on windows , see https://github.com/dotnet/maui/issues/29930

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue11812.cs:15

• [nitpick] The test category is set to UITestCategories.Border, which doesn't match ContentView behavior. Consider creating or using a more appropriate category (e.g., UITestCategories.ContentView or UITestCategories.Issues).

[Category(UITestCategories.Border)]

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue11812.cs:18

• The test currently only checks that tapping the button does not crash. To fully validate the fix, add an assertion such as App.WaitForElement("SubContent") to confirm the styled child label appears after the dynamic content change.

App.WaitForElement("ChangeInnerContent");