Fix CollectionView.Header is header is not scrollable in Android platform

[SuthiYuvaraj]

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 Description:

CollectionView.Header content is not scrollable on Android platform when it contains scrollable content like ScrollView with ListView.

Root Cause:

When the scrollable content is loaded inside the Header of the collectionview , touch is not passed to the internal scrollable control , which is handled by the TemplatedContentView in CollectionView.

Fix Description:

I have included the Touch Events in ItemContentView to handle the touch when the content is scrollable inside the header/ footer , Remaining cases it will not affects the previous behavior

Issues Fixed

Fixes #22120

Tested the behaviour in the following platforms

• Android
• Windows
• iOS
• Mac

Output Screenshot

Before Issue Fix	After Issue Fix
Before.mov	After.mov

[dotnet-policy-service]

Hey there @@SuthiYuvaraj! 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]

/rebase

[jsuarezruiz]

@SuthiYuvaraj Could you rebase to fix the conflict?

[rmarinho]

🤖 AI Summary

📊 Expand Full Review

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🔍 Pre-Flight — Context & Validation

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📝 Review Session — Create problems-report.html · 05a9003

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Issue: #22120 - CollectionView.Header is not scrollable in Android platform
PR: #31661 - Fix CollectionView.Header is header is not scrollable in Android platform
Platforms Affected: Android only
PR Status: DRAFT
Files Changed: 2 implementation files, 2 test files

Issue Summary

On Android, when CollectionView.Header contains scrollable content (e.g., a ScrollView wrapping a ListView), touch events are not passed to the inner scrollable control. The RecyclerView intercepts all touch events, preventing the header's ScrollView from scrolling.

Fix Approach

Override DispatchTouchEvent and OnInterceptTouchEvent in ItemContentView (Android-specific ViewGroup). On MotionEventActions.Down for header/footer content, call Parent?.RequestDisallowInterceptTouchEvent(true) to prevent the parent RecyclerView from intercepting touch events. On Up/Cancel events, reset with RequestDisallowInterceptTouchEvent(false).

Files Changed

• Fix files:
  • src/Controls/src/Core/Handlers/Items/Android/ItemContentView.cs (+71)
  • src/Controls/src/Core/PublicAPI/net-android/PublicAPI.Unshipped.txt (+2)
• Test files:
  • src/Controls/tests/TestCases.HostApp/Issues/Issue22120.cs (+86, added)
  • src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue22120.cs (+27, added)

PR Discussion

• MAUI team member (jsuarezruiz) triggered UI tests and requested a rebase
• No inline review comments
• No reviewer rejections

Disagreements / Edge Cases

File:Line	Concern	Notes
ItemContentView.cs	IsHeaderOrFooterContent() called on every touch event (performance)	Traverses logical parent tree on each touch
ItemContentView.cs	RequestDisallowInterceptTouchEvent(true) applied to ALL header/footer content on DOWN, not just scrollable	Could affect non-scrollable headers
ItemContentView.cs	DispatchTouchEvent and OnInterceptTouchEvent become public API	PublicAPI.Unshipped.txt updated, but are these appropriate as public API?
ItemContentView.cs	FindParentItemsView() traverses MAUI logical parent chain	May not work with HeaderTemplate

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #31661	Override DispatchTouchEvent/OnInterceptTouchEvent in ItemContentView to call RequestDisallowInterceptTouchEvent for header/footer content	⏳ PENDING (Gate)	ItemContentView.cs (+71), PublicAPI.Unshipped.txt (+2)	Original PR

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🚦 Gate — Test Verification

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📝 Review Session — Create problems-report.html · 05a9003

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Result: ✅ PASSED
Platform: android
Mode: Full Verification
Test Filter: Issue22120

• Tests FAIL without fix ✅
• Tests PASS with fix ✅

The tests correctly catch the bug (CollectionView.Header not scrollable in Android) and confirm the PR's fix resolves it.

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🔧 Fix — Analysis & Comparison

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📝 Review Session — Create problems-report.html · 05a9003

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Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #31661	Override DispatchTouchEvent/OnInterceptTouchEvent in ItemContentView to call RequestDisallowInterceptTouchEvent for header/footer content	✅ PASS (Gate)	ItemContentView.cs (+71), PublicAPI.Unshipped.txt (+2)	Original PR

Exhausted: No (try-fix skipped due to rate limit errors on task agent - 429 Too Many Requests after 3 attempts)
Selected Fix: PR's fix - Gate confirmed tests pass. try-fix exploration blocked by environment rate limits.

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📋 Report — Final Recommendation

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📝 Review Session — Create problems-report.html · 05a9003

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⚠️ Final Recommendation: REQUEST CHANGES

Summary

PR #31661 fixes Android-specific issue where CollectionView.Header containing scrollable content (e.g. ScrollView with ListView) was not scrollable due to RecyclerView intercepting all touch events. The fix uses RequestDisallowInterceptTouchEvent, which is the correct Android mechanism for nested scrolling. Gate verified tests fail without the fix and pass with it. However, several issues need to be addressed before merging.

Root Cause

Android's RecyclerView intercepts all touch events (via onInterceptTouchEvent) to handle its own scrolling, preventing nested scrollable views inside the header from receiving touch events. The fix overrides OnInterceptTouchEvent and DispatchTouchEvent in ItemContentView to call Parent?.RequestDisallowInterceptTouchEvent(true) on DOWN events for header/footer content, temporarily disabling RecyclerView's touch interception.

Fix Quality

The core approach (RequestDisallowInterceptTouchEvent) is the standard Android pattern for nested scrolling and is technically correct. However:

Issues Found

1. Unused Import (code quality)

using AndroidX.RecyclerView.Widget;  // Added but never used

RecyclerView is imported but not referenced anywhere in the modified code. Should be removed.

2. HeaderTemplate Edge Case (functional limitation)
IsHeaderOrFooterContent() checks ReferenceEquals(View, structuredItemsView.Header). When HeaderTemplate is used instead of Header, structuredItemsView.Header returns null and the fix won't activate. This is an undocumented limitation that affects a common usage pattern. Should either be documented or handled.

3. Touch Event Logic Review
Setting RequestDisallowInterceptTouchEvent(true) unconditionally on DOWN for ALL header/footer content (not just when the content has scrollable children) is overly broad. A tap on a non-scrollable header button will also prevent RecyclerView from later receiving MOVE events until UP. While functionally correct (UP resets the flag), this is more aggressive than necessary and could potentially cause subtle interaction issues.

4. PR Is In DRAFT State
The PR is marked as draft. This may indicate the author is still working on it.

Test Coverage

Tests are well-structured:

• Issue22120.cs (HostApp): Creates CollectionView with ScrollView header containing 15-item ListView
• Issue22120.cs (SharedTests): Verifies scroll down and scroll up behavior with element visibility checks
• Category: UITestCategories.CollectionView ✓
• Platform: PlatformAffected.Android ✓

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #31661	Override DispatchTouchEvent/OnInterceptTouchEvent in ItemContentView to use RequestDisallowInterceptTouchEvent	✅ PASS (Gate)	ItemContentView.cs (+71), PublicAPI.Unshipped.txt (+2)	Original PR

try-fix: Skipped due to environment rate limit (429 errors). PR's fix is the only validated candidate.

Changes Requested

1. Remove unused import using AndroidX.RecyclerView.Widget;
2. Document or fix HeaderTemplate limitation - add a comment or extend to handle templated headers
3. Mark PR as ready for review (remove draft status) when changes are complete

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📋 Expand PR Finalization Review

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Title: ✅ Good

Current: Fix CollectionView.Header is header is not scrollable in Android platform

Description: ⚠️ Needs Update

• Grammatical error: "is header is" (double "is")
• Missing platform prefix [Android]
• Verbose phrasing

✨ 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!

Root Cause

On Android, the RecyclerView that backs CollectionView intercepts all touch events to handle its own scrolling. When a scrollable control (e.g., ScrollView containing a ListView) is placed inside the CollectionView.Header or CollectionView.Footer, the RecyclerView consumes the touch events before they can reach the inner scrollable view, making the header/footer content unscrollable.

Description of Change

Added OnInterceptTouchEvent and DispatchTouchEvent overrides to ItemContentView (Android) to pass touch events through to scrollable header/footer content.

When the ItemContentView is rendering a header or footer (detected by comparing the logical view reference against StructuredItemsView.Header / StructuredItemsView.Footer):

• OnInterceptTouchEvent (Down): Calls Parent.RequestDisallowInterceptTouchEvent(true) to prevent the parent RecyclerView from stealing touch events, then returns false so child views can handle the gesture.
• DispatchTouchEvent (Up/Cancel): Calls Parent.RequestDisallowInterceptTouchEvent(false) to restore normal RecyclerView touch interception after the gesture ends.

This is the standard Android nested scrolling pattern. Regular CollectionView items are unaffected — the overrides are no-ops when IsHeaderOrFooterContent() returns false.

Note: This fix applies when Header/Footer is set directly as a View. If HeaderTemplate/FooterTemplate is used (DataTemplate), the fix does not apply because the ReferenceEquals check compares against the template object, not the inflated view.

Issues Fixed

Fixes #22120

Platforms Tested

• Android
• Windows
• iOS
• Mac

Code Review: ⚠️ Issues Found

Code Review – PR #31661

🔴 Critical Issues

Unused using Directives

File: src/Controls/src/Core/Handlers/Items/Android/ItemContentView.cs

Problem: The PR adds two using directives that are not referenced anywhere in the new or existing code:

using AndroidX.Core.Widget;       // unused
using AndroidX.RecyclerView.Widget; // unused

Neither NestedScrollView (from AndroidX.Core.Widget) nor RecyclerView (from AndroidX.RecyclerView.Widget) is referenced in the new logic. The IsHeaderOrFooterContent / FindParentItemsView methods work purely with MAUI logical types (IView, StructuredItemsView).

Recommendation: Remove both unused using directives before merge.

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🟡 Suggestions

1. Fix Does Not Cover HeaderTemplate / FooterTemplate

File: src/Controls/src/Core/Handlers/Items/Android/ItemContentView.cs — IsHeaderOrFooterContent()

The ReferenceEquals check compares View (the MAUI virtual view) to structuredItemsView.Header:

return ReferenceEquals(View, structuredItemsView.Header) ||
       ReferenceEquals(View, structuredItemsView.Footer);

When Header / Footer is set directly as a View, this works correctly. However, when HeaderTemplate / FooterTemplate is used (a DataTemplate), structuredItemsView.Header holds the DataTemplate object, not the inflated view — so the check will always return false and the fix won't apply.

Recommendation: Either document this known limitation in a code comment and in the PR description, or extend the fix to handle the template case. At minimum, a // Note: Does not handle HeaderTemplate/FooterTemplate comment would prevent future confusion.

2. Extra Blank Line in DispatchTouchEvent

File: src/Controls/src/Core/Handlers/Items/Android/ItemContentView.cs

There is an extra blank line inside the outer if block:

public override bool DispatchTouchEvent(MotionEvent e)
{
    if (IsHeaderOrFooterContent())
    {
        // ← extra blank line here
        if (e.Action == MotionEventActions.Up || e.Action == MotionEventActions.Cancel)
        {

Recommendation: Remove the spurious blank line for consistency with the rest of the file's style.

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✅ Looks Good

• Core fix logic is correct: RequestDisallowInterceptTouchEvent(true) on MotionEventActions.Down / false on Up/Cancel is the standard Android pattern for nested scroll containers and is widely used in the Android ecosystem.
• Regular items unaffected: IsHeaderOrFooterContent() returns false for non-header/footer ItemContentView instances, so existing RecyclerView item behavior is unchanged.
• PublicAPI.Unshipped.txt updated: Both new public overrides (DispatchTouchEvent, OnInterceptTouchEvent) are correctly added to net-android/PublicAPI.Unshipped.txt.
• UI test included: Issue22120.cs tests scroll-up and scroll-down on a ScrollView inside CollectionView.Header with proper AutomationId attributes. The test uses [Category(UITestCategories.CollectionView)] (single category, correct).
• Logical tree traversal: FindParentItemsView() traverses the MAUI logical parent chain (not the Android view hierarchy), which is the correct approach for finding the owning StructuredItemsView.

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[MauiBot]

⚠️ Merge Conflict Detected — This PR has merge conflicts with its target branch. Please rebase onto the target branch and resolve the conflicts.