[Android] Implemented material3 support for Label

[SyedAbdulAzeemSF4852]

Description of Change

• This pull request introduces support for Material3 styling for Label controls on Android by conditionally using a new handler and platform view. The changes ensure that when Material3 is enabled, a new LabelHandler2 and MauiMaterialTextView are used, which properly handle formatted text and layout events. The update also improves event management in the Label control.

Material3 support for Label on Android:

• Added conditional logic in AppHostBuilderExtensions.cs to use LabelHandler2 with MauiMaterialTextView when Material3 is enabled on Android; otherwise, the default handler is used.
• Introduced the internal LabelHandler2 class, which overrides CreatePlatformView to return a MauiMaterialTextView.
• Added the new internal MauiMaterialTextView class, which extends MaterialTextView and optimizes layout event handling for formatted text.

Label control event management improvements:

• Updated Label.Android.cs to properly attach and detach LayoutChanged event handlers for both MauiTextView and MauiMaterialTextView, preventing memory leaks and ensuring correct event handling.
• Improved null-checking and early returns in the OnLayoutChanged method for robustness.

Preparatory/cleanup changes:

• Removed the [ElementHandler<LabelHandler>] attribute from the Label class and replaced it with conditional dependency injection registration. This change was necessary because the static attribute approach cannot support runtime handler selection based on feature flags.

Issues Fixed

Fixes #33598

Output

Material2	Material3

[Copilot]

Pull request overview

This PR implements Material3 support for the Label control on Android by introducing conditional handler selection and a new Material3-specific platform view. The implementation ensures proper event management and formatted text handling when Material3 is enabled.

Changes:

• Added runtime-based handler registration that selects LabelHandler2 with MauiMaterialTextView when Material3 is enabled on Android
• Improved event handling in Label.Android.cs to support both MauiTextView and MauiMaterialTextView with proper cleanup
• Removed static ElementHandler attribute from Label class to enable dynamic handler selection

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
MauiMaterialTextView.cs	New Material3 TextView implementation with optimized layout event handling for formatted text
LabelHandler.Android.cs	Added LabelHandler2 that creates Material3 TextView instances
Label.cs	Removed static handler attribute to support runtime handler selection
Label.Android.cs	Enhanced event management to handle both Material2 and Material3 TextViews
AppHostBuilderExtensions.cs	Added conditional handler registration based on Material3 feature flag

[kannanrs]

Request to add usage of all materialstyles with this Implemented like threads...

TIA

[rmarinho]

🤖 AI Summary

📊 Expand Full Review

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🔍 Pre-Flight — Context & Validation

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📝 Review Session — Used ILabelHandler and improved formatted text comments · ee19ad1

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Issue: #33598 - Implement Material3 Support for Label
PR: #33599 - [Android] Implemented material3 support for Label
Platforms Affected: Android only
Files Changed: 5 files (1 new file, 4 modified)

Issue Summary

When UseMaterial3 MSBuild property is enabled, the Label control should use Material3 visual design system on Android. The current implementation does not reflect Material3 behavior — Label should use Material3-specific styling with updated text colors, enhanced formatted text rendering, and appropriate Material3 theme resources.

Files Changed

Fix files:

• src/Controls/src/Core/Hosting/AppHostBuilderExtensions.cs (+12) - Conditional handler registration based on RuntimeFeature.IsMaterial3Enabled
• src/Controls/src/Core/Label/Label.Android.cs (+36, -11) - Updated handler change logic & event cleanup for both view types
• src/Controls/src/Core/Label/Label.cs (-1) - Remove [ElementHandler<LabelHandler>] attribute
• src/Core/src/Handlers/Label/LabelHandler.Android.cs (+9) - New LabelHandler2 class
• src/Core/src/Platform/Android/Material3Controls/MauiMaterialTextView.cs (+38, new file) - New MauiMaterialTextView extending MaterialTextView

Test files: None

PR Approach

1. Removes [ElementHandler<LabelHandler>] attribute from Label class (static attribute can't support runtime selection)
2. Adds MauiMaterialTextView extending MaterialTextView with layout event optimization (only fires for formatted/spannable text)
3. Adds LabelHandler2 that creates MauiMaterialTextView as platform view
4. Conditionally registers LabelHandler2 when RuntimeFeature.IsMaterial3Enabled on Android (all other paths use LabelHandler)
5. Updates Label.Android.cs to handle both MauiTextView and MauiMaterialTextView for LayoutChanged events using DetachLayoutChanged() helper

Reviewer Comments

• copilot-pull-request-reviewer (resolved): Flagged fragile Java.Lang.String type check in MauiMaterialTextView.SetText(), suggested using Android.Text.SpannableString — NOT addressed by author
• copilot-pull-request-reviewer (resolved, accepted): Suggested using ILabelHandler pattern match — author accepted this suggestion
• kannanrs: Requested usage of all material styles similar to other controls — no response from author
• kubaflo (Feb 17, CHANGES_REQUESTED): "Could you please apply the AI Summary suggestions?" — pending

Disagreements / Edge Cases

File:Line	Reviewer Says	Author Says	Status
MauiMaterialTextView.cs:24	Type check text is not Java.Lang.String is fragile; use Android.Text.ISpanned	Not addressed	⚠️ UNRESOLVED
PR comment	Use all material styles similar to other controls	Not addressed	OUT OF SCOPE

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #33599	Add LabelHandler2 + MauiMaterialTextView, conditional registration in AppHostBuilderExtensions	⏳ PENDING (Gate)	5 files	Original PR

Prior Agent Review

A prior complete agent review exists (posted by rmarinho on Feb 17, 2026, at commit ee19ad1):

• Gate: ❌ FAILED (no tests exist)
• Report: REQUEST CHANGES
  No new commits have been pushed since that review.

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🚦 Gate — Test Verification

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📝 Review Session — Used ILabelHandler and improved formatted text comments · ee19ad1

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Result: ❌ FAILED
Platform: android
Mode: Test Existence Check

Finding

No test files exist for issue #33598 or PR #33599.

Searched:

• src/Controls/tests/TestCases.HostApp/Issues/ for *33598* or *33599* files
• src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/ for matching files
• No references to LabelHandler2, MauiMaterialTextView, or Material3.*Label in any test project

Conclusion

Tests are missing entirely. Cannot verify that tests catch the bug (or validate the fix).
The PR author did not include any UI tests or unit tests with this PR.

Action Required: Tests need to be created. The write-tests-agent can help create them.

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🔧 Fix — Analysis & Comparison

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📝 Review Session — Used ILabelHandler and improved formatted text comments · ee19ad1

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Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #33599	Add LabelHandler2 + MauiMaterialTextView, conditional registration	⏳ PENDING (Gate)	5 files	Original PR - Gate not passed

Exhausted: N/A (skipped - Gate failed, no tests to run)
Selected Fix: N/A - Gate did not pass

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📋 Report — Final Recommendation

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📝 Review Session — Used ILabelHandler and improved formatted text comments · ee19ad1

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❌ Final Recommendation: REQUEST CHANGES

Summary

PR #33599 implements Material3 support for the Label control on Android by introducing LabelHandler2 and MauiMaterialTextView. The overall architecture is sound and consistent with how other controls (CollectionView, CarouselView) implement Material3 support. However, the PR is missing tests and has an unaddressed code quality concern flagged by the Copilot reviewer.

Gate Status

Gate ❌ FAILED — No tests exist for issue #33598 or PR #33599. The PR does not include any UI tests or unit tests to verify Material3 Label behavior or catch regressions.

Root Cause (Issue #33598)

When UseMaterial3 is enabled on Android, the Label control was using MauiTextView (extends AppCompatTextView) instead of MaterialTextView. Material3 theming on Android requires MaterialTextView as the base view to properly apply Material3 typography, color roles, and state-layer behaviors. The [ElementHandler<LabelHandler>] static attribute on the Label class also prevented runtime handler selection based on feature flags.

Fix Quality Assessment

Positive aspects:

• Architecture is sound: LabelHandler2 + MauiMaterialTextView keeps Material3 code isolated from the default path — consistent with how CollectionView implements its Material3 handler
• Conditional handler registration via RuntimeFeature.IsMaterial3Enabled in AppHostBuilderExtensions.cs is the correct pattern
• Removing [ElementHandler<LabelHandler>] is correct — CollectionView (which also uses conditional Material3 registration) does NOT use [ElementHandler] either
• DetachLayoutChanged() helper refactor is good defensive programming that prevents double-subscription and memory leaks
• Using ILabelHandler pattern match correctly handles both handler types (Copilot suggestion accepted)
• MauiMaterialContextThemeWrapper.Create(context) reused consistently with other Material3 controls
• TODO: Material3 - make it public in .net 11 comments show a planned migration path

Issues to address:

1. Missing tests (blocking): No UI tests or device tests were added. For a feature addition of this magnitude, at minimum an Android UI test demonstrating Material3 Label rendering should be included.

2. Fragile type check in MauiMaterialTextView.SetText() (should fix): The check _isFormatted = text is not Java.Lang.String is fragile. Any non-Java.Lang.String value is treated as "formatted text," which would incorrectly fire layout events for other ICharSequence implementations that aren't spannable. The Copilot review flagged this and the thread was marked resolved, but the code was NOT changed. Recommend:

   _isFormatted = text is Android.Text.ISpanned;

3. LayoutChanged event visibility: MauiMaterialTextView.LayoutChanged is internal, but MauiTextView.LayoutChanged is public. If MauiMaterialTextView is made public in .NET 11, this will need to be updated. Consider making it public now to match.

4. Missing trailing newlines: Both LabelHandler.Android.cs and MauiMaterialTextView.cs are missing trailing newlines (POSIX violation, causes noise in diffs).

Requested Changes

1. Add tests: Create at minimum an Android UI test for issue Implement Material3 Support for Label #33598:

   • src/Controls/tests/TestCases.HostApp/Issues/Issue33598.cs — ContentPage with Label using formatted text under Material3
   • src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue33598.cs — NUnit test with [Category(UITestCategories.Label)]
   • The write-tests-agent can help create these

2. Fix the fragile type check in MauiMaterialTextView.SetText(): Use text is Android.Text.ISpanned instead of text is not Java.Lang.String

3. Make LayoutChanged event public to match MauiTextView

4. Add trailing newlines to LabelHandler.Android.cs and MauiMaterialTextView.cs

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📋 Expand PR Finalization Review

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Title: ✅ Good

Current: [Android] Implemented material3 support for Label

Description: ✅ Good

• "Implemented" is verbose past-tense. MAUI PR convention uses imperative/noun forms (e.g., "Add", "Fix", "Label:").
• Could be more specific about what mechanism is used.
  Missing Elements:

** Prepend the required NOTE block at the very top. The rest of the description is good and should be kept as-is.

Recommended action: Add NOTE block, keep existing description content.

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Phase 2: Code Review

See code-review.md for full findings.

Summary:

• 🔴 No critical issues
• 🟡 2 minor issues (missing newlines at EOF, _isFormatted check explicitness)
• ✅ Implementation is architecturally sound and consistent with existing Material3 patterns

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Verdict

The PR description accurately matches the implementation. The description content is good quality. The only required change is prepending the NOTE block. A new recommended description has been written to recommended-description.md.

✨ Suggested PR Description

[!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!

Description of Change

• This pull request introduces support for Material3 styling for Label controls on Android by conditionally using a new handler and platform view. The changes ensure that when Material3 is enabled, a new LabelHandler2 and MauiMaterialTextView are used, which properly handle formatted text and layout events. The update also improves event management in the Label control.

Material3 support for Label on Android:

• Added conditional logic in AppHostBuilderExtensions.cs to use LabelHandler2 with MauiMaterialTextView when Material3 is enabled on Android; otherwise, the default handler is used.
• Introduced the internal LabelHandler2 class, which overrides CreatePlatformView to return a MauiMaterialTextView.
• Added the new internal MauiMaterialTextView class, which extends MaterialTextView and optimizes layout event handling for formatted text.

Label control event management improvements:

• Updated Label.Android.cs to properly attach and detach LayoutChanged event handlers for both MauiTextView and MauiMaterialTextView, preventing memory leaks and ensuring correct event handling.
• Improved null-checking and early returns in the OnLayoutChanged method for robustness.

Preparatory/cleanup changes:

• Removed the [ElementHandler] attribute from the Label class and replaced it with conditional dependency injection registration. This change was necessary because the static attribute approach cannot support runtime handler selection based on feature flags.

Issues Fixed

Fixes #33598

Output

Material2	Material3

Code Review: ⚠️ Issues Found

Code Review — PR #33599

Code Review Findings

🔴 Critical Issues

None.

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🟡 Suggestions

1. Missing newline at end of file in two files

• Files: src/Core/src/Handlers/Label/LabelHandler.Android.cs, src/Core/src/Platform/Android/Material3Controls/MauiMaterialTextView.cs
• Problem: Both diff patches end with \\ No newline at end of file. The .NET MAUI repo expects newlines at end of file per standard C# formatting.
• Recommendation: Add a trailing newline to both files.

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2. _isFormatted type check in MauiMaterialTextView.SetText is fragile

• File: src/Core/src/Platform/Android/Material3Controls/MauiMaterialTextView.cs (line 24)
• Problem: The check text is not Java.Lang.String is a negative exclusion. This was flagged in the original Copilot review thread (resolved). While it mirrors the Java PlatformAppCompatTextView behavior exactly (!(text instanceof String)), it's not self-documenting. If a new non-formatted, non-String ICharSequence type were introduced in the future, it could produce false positives.
• Recommendation: Use a more explicit positive check: text is Android.Text.SpannableString or Android.Text.SpannableStringBuilder or add a comment documenting that the Java implementation uses the same pattern.

// Mirrors PlatformAppCompatTextView.java: !(text instanceof String) means formatted
_isFormatted = text is not Java.Lang.String;

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✅ Looks Good

AppHostBuilderExtensions.cs — Conditional DI Registration

• Using RuntimeFeature.IsMaterial3Enabled at startup for handler selection is consistent with how other Material3 checks work in the codebase (e.g., CheckBoxExtensions.cs, MauiMaterialContextThemeWrapper.cs). Evaluated once at startup, which is the correct place.

Label.Android.cs — DetachLayoutChanged refactoring

• Extracting detach logic into a dedicated DetachLayoutChanged() method called at the start of OnHandlerChangedCore is clean and correctly prevents memory leaks when switching handlers.
• Switching to ILabelHandler pattern match (Handler is not ILabelHandler { PlatformView: var platformView }) addresses the review comment and correctly handles both LabelHandler and LabelHandler2.

LabelHandler2 covariant return type

• LabelHandler.CreatePlatformView() returns AppCompatTextView. LabelHandler2 overrides it to return MauiMaterialTextView. Since MaterialTextView extends AppCompatTextView, this is a valid C# 9+ covariant return override.

MauiMaterialTextView — Reimplemented vs. OnLayoutFormatted hook

• MauiTextView extends PlatformAppCompatTextView (Java) which has an onLayoutFormatted hook that only fires for formatted text. MauiMaterialTextView extends MaterialTextView which does not have this hook, so the PR correctly reimplements the same _isFormatted pattern in C#. The implementation is semantically equivalent to the Java version.

[ElementHandler<LabelHandler>] removal from Label.cs

• Correct approach. The static attribute cannot support runtime selection based on feature flags. The explicit DI registration in AppHostBuilderExtensions.cs correctly covers all platforms: Android with Material3 (LabelHandler2), Android without Material3 (LabelHandler), and all other platforms (LabelHandler).

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[kubaflo]

Could you please apply the AI Summary suggestions?

[SyedAbdulAzeemSF4852]

Could you please apply the AI Summary suggestions?

@kubaflo, I have reviewed the AI summary and implemented the valid suggestions.

[sheiksyedm]

/azp run maui-pr-uitests

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[kubaflo]

@sheiksyedm thank you for adding the label <3
@SyedAbdulAzeemSF4852 looks good!