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[Android] Optimize MauiWindowInsetListener registry with ConditionalWeakTable #32447

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[Android] Optimize MauiWindowInsetListener registry with ConditionalWeakTable #32447

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b614c65
Initial plan
Copilot Nov 7, 2025
48c9648
Replace List with ConditionalWeakTable for O(n) performance
Copilot Nov 7, 2025
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54 changes: 9 additions & 45 deletions src/Core/src/Platform/Android/MauiWindowInsetListener.cs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using Android.Content;
using Android.Views;
using AndroidX.Core.Graphics;
Expand All @@ -12,11 +13,6 @@

namespace Microsoft.Maui.Platform
{
/// <summary>
/// Registry entry for tracking view instances and their associated listeners.
/// Uses WeakReference to avoid memory leaks when views are disposed.
/// </summary>
internal record ViewEntry(WeakReference<object> View, MauiWindowInsetListener Listener);

/// <summary>
/// Manages window insets and safe area handling for Android views.
Expand All @@ -36,8 +32,9 @@ internal class MauiWindowInsetListener : WindowInsetsAnimationCompat.Callback, I
// Static tracking for views that have local inset listeners.
// This registry allows child views to find their appropriate listener without
// relying on a global activity-level listener.
// Uses ConditionalWeakTable for O(1) lookup and automatic cleanup.
// Thread Safety: All access must be on UI thread (enforced by Android's threading model).
static readonly List<ViewEntry> _registeredViews = new();
static readonly ConditionalWeakTable<AView, MauiWindowInsetListener> _registeredViews = new();

/// <summary>
/// Registers a view to use this local listener instead of the global one.
Expand All @@ -47,23 +44,7 @@ internal class MauiWindowInsetListener : WindowInsetsAnimationCompat.Callback, I
/// <param name="view">The view to register</param>
internal void RegisterView(AView view)
{
// Clean up dead references and check for existing registration
for (int i = _registeredViews.Count - 1; i >= 0; i--)
{
var entry = _registeredViews[i];
if (!entry.View.TryGetTarget(out var existingView))
{
_registeredViews.RemoveAt(i);
}
else if (existingView == view)
{
// Already registered, no need to add again
return;
}
}

// Add this view to the registry
_registeredViews.Add(new ViewEntry(new WeakReference<object>(view), this));
_registeredViews.AddOrUpdate(view, this);
}

/// <summary>
Expand All @@ -73,14 +54,10 @@ internal void RegisterView(AView view)
/// <param name="view">The view to unregister</param>
internal static MauiWindowInsetListener? UnregisterView(AView view)
{
for (int i = _registeredViews.Count - 1; i >= 0; i--)
if (_registeredViews.TryGetValue(view, out var listener))
{
if (_registeredViews[i].View.TryGetTarget(out var registeredView) && registeredView == view)
{
var listener = _registeredViews[i].Listener;
_registeredViews.RemoveAt(i);
return listener;
}
_registeredViews.Remove(view);
return listener;
}
return null;
}
Expand All @@ -107,22 +84,9 @@ internal void RegisterView(AView view)
return null;
}

if (parent is AView parentView)
if (parent is AView parentView && _registeredViews.TryGetValue(parentView, out var listener))
{
// Check if this parent view is registered
// Clean up dead references while searching
for (int i = _registeredViews.Count - 1; i >= 0; i--)
{
var entry = _registeredViews[i];
if (!entry.View.TryGetTarget(out var registeredView))
{
_registeredViews.RemoveAt(i);
}
else if (ReferenceEquals(registeredView, parentView))
{
return entry.Listener;
}
}
return listener;
}

parent = parent.Parent;
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