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[iOS] Fix memory leak in CarouselViewHandler2 #29719

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Merged
merged 3 commits into from
May 30, 2025
Merged

[iOS] Fix memory leak in CarouselViewHandler2 #29719

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32edad4
fix CarouselViewHandler2 memory leak
bhavanesh2001 May 28, 2025
ec3249e
enable cv2 memory tests
bhavanesh2001 May 28, 2025
9d22914
formatting
bhavanesh2001 May 28, 2025
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121 changes: 8 additions & 113 deletions src/Controls/src/Core/Handlers/Items2/CarouselViewHandler2.iOS.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -40,121 +40,16 @@ protected override CarouselViewController2 CreateController(CarouselView newElem
protected override UICollectionViewLayout SelectLayout()
{
bool isHorizontal = VirtualView.ItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal;
var peekInsets = VirtualView.PeekAreaInsets;

NSCollectionLayoutDimension itemWidth = NSCollectionLayoutDimension.CreateFractionalWidth(1);
NSCollectionLayoutDimension itemHeight = NSCollectionLayoutDimension.CreateFractionalHeight(1);
NSCollectionLayoutDimension groupWidth = NSCollectionLayoutDimension.CreateFractionalWidth(1);
NSCollectionLayoutDimension groupHeight = NSCollectionLayoutDimension.CreateFractionalHeight(1);
nfloat itemSpacing = 0;
NSCollectionLayoutGroup group = null;
var weakItemsView = new WeakReference<CarouselView>(ItemsView);
var weakController = new WeakReference<CarouselViewController2>((CarouselViewController2)Controller);

var layout = new UICollectionViewCompositionalLayout((sectionIndex, environment) =>
{
if (VirtualView is null)
{
return null;
}
double sectionMargin = 0.0;
if (!isHorizontal)
{
sectionMargin = VirtualView.PeekAreaInsets.VerticalThickness / 2;
var newGroupHeight = environment.Container.ContentSize.Height - VirtualView.PeekAreaInsets.VerticalThickness;
groupHeight = NSCollectionLayoutDimension.CreateAbsolute((nfloat)newGroupHeight);
groupWidth = NSCollectionLayoutDimension.CreateFractionalWidth(1);
}
else
{
sectionMargin = VirtualView.PeekAreaInsets.HorizontalThickness / 2;
var newGroupWidth = environment.Container.ContentSize.Width - VirtualView.PeekAreaInsets.HorizontalThickness;
groupWidth = NSCollectionLayoutDimension.CreateAbsolute((nfloat)newGroupWidth);
groupHeight = NSCollectionLayoutDimension.CreateFractionalHeight(1);
}

// Each item has a size
var itemSize = NSCollectionLayoutSize.Create(itemWidth, itemHeight);
// Create the item itself from the size
var item = NSCollectionLayoutItem.Create(layoutSize: itemSize);

//item.ContentInsets = new NSDirectionalEdgeInsets(0, itemInset, 0, 0);

var groupSize = NSCollectionLayoutSize.Create(groupWidth, groupHeight);

if (OperatingSystem.IsIOSVersionAtLeast(16))
{
group = isHorizontal ? NSCollectionLayoutGroup.GetHorizontalGroup(groupSize, item, 1) :
NSCollectionLayoutGroup.GetVerticalGroup(groupSize, item, 1);
}
else
{
group = isHorizontal ? NSCollectionLayoutGroup.CreateHorizontal(groupSize, item, 1) :
NSCollectionLayoutGroup.CreateVertical(groupSize, item, 1);
}

// Create our section layout
var section = NSCollectionLayoutSection.Create(group: group);
section.InterGroupSpacing = itemSpacing;
section.OrthogonalScrollingBehavior = isHorizontal ? UICollectionLayoutSectionOrthogonalScrollingBehavior.GroupPagingCentered : UICollectionLayoutSectionOrthogonalScrollingBehavior.None;
section.VisibleItemsInvalidationHandler = (items, offset, env) =>
{
//This will allow us to SetPosition when we are scrolling the items
//based on the current page
var page = (offset.X + sectionMargin) / env.Container.ContentSize.Width;

// Check if we not are at the beginning or end of the page and if we have items
if (Math.Abs(page % 1) > (double.Epsilon * 100) || Controller.ItemsSource.ItemCount <= 0)
{
return;
}

var pageIndex = (int)page;
var carouselPosition = pageIndex;

var cv2Controller = (CarouselViewController2)Controller;

//If we are looping, we need to get the correct position
if (ItemsView.Loop)
{
var maxIndex = (Controller.ItemsSource as ILoopItemsViewSource).LoopCount - 1;

//To mimic looping, we needed to modify the ItemSource and inserted a new item at the beginning and at the end
if (pageIndex == maxIndex)
{
//When at last item, we need to change to 2nd item, so we can scroll right or left
pageIndex = 1;
}
else if (pageIndex == 0)
{
//When at first item, need to change to one before last, so we can scroll right or left
pageIndex = maxIndex - 1;
}

//since we added one item at the beginning of our ItemSource, we need to subtract one
carouselPosition = pageIndex - 1;

if (ItemsView.Position != carouselPosition)
{
//If we are updating the ItemsSource, we don't want to scroll the CollectionView
if (cv2Controller.IsUpdating())
{
return;
}

var goToIndexPath = cv2Controller.GetScrollToIndexPath(carouselPosition);

//This will move the carousel to fake the loop
Controller.CollectionView.ScrollToItem(NSIndexPath.FromItemSection(pageIndex, 0), UICollectionViewScrollPosition.Left, false);

}
}

//Update the CarouselView position
cv2Controller?.SetPosition(carouselPosition);

};
return section;
});

return layout;
return LayoutFactory2.CreateCarouselLayout(
isHorizontal,
peekInsets,
weakItemsView,
weakController);
}

protected override void ScrollToRequested(object sender, ScrollToRequestEventArgs args)
Expand Down
132 changes: 132 additions & 0 deletions src/Controls/src/Core/Handlers/Items2/iOS/LayoutFactory2.cs
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,8 @@
using System.Collections.Generic;
using System.Runtime.InteropServices;
using CoreGraphics;
using Foundation;
using Microsoft.Maui.Controls.Handlers.Items;
using UIKit;

namespace Microsoft.Maui.Controls.Handlers.Items2;
Expand Down Expand Up @@ -261,6 +263,136 @@ public static UICollectionViewLayout CreateHorizontalGrid(GridItemsLayout gridIt
gridItemsLayout.Span);


#nullable disable
public static UICollectionViewLayout CreateCarouselLayout(
bool isHorizontal,
Thickness peekAreaInsets,
WeakReference<CarouselView> weakItemsView,
WeakReference<CarouselViewController2> weakController)
{
NSCollectionLayoutDimension itemWidth = NSCollectionLayoutDimension.CreateFractionalWidth(1);
NSCollectionLayoutDimension itemHeight = NSCollectionLayoutDimension.CreateFractionalHeight(1);
NSCollectionLayoutDimension groupWidth = NSCollectionLayoutDimension.CreateFractionalWidth(1);
NSCollectionLayoutDimension groupHeight = NSCollectionLayoutDimension.CreateFractionalHeight(1);
nfloat itemSpacing = 0;
NSCollectionLayoutGroup group = null;

var layout = new UICollectionViewCompositionalLayout((sectionIndex, environment) =>
{
if (!weakItemsView.TryGetTarget(out var itemsView) || !weakController.TryGetTarget(out var controller))
{
return null;
}

double sectionMargin = 0.0;

if (!isHorizontal)
{
sectionMargin = peekAreaInsets.VerticalThickness / 2;
var newGroupHeight = environment.Container.ContentSize.Height - peekAreaInsets.VerticalThickness;
groupHeight = NSCollectionLayoutDimension.CreateAbsolute((nfloat)newGroupHeight);
groupWidth = NSCollectionLayoutDimension.CreateFractionalWidth(1);
}
else
{
sectionMargin = peekAreaInsets.HorizontalThickness / 2;
var newGroupWidth = environment.Container.ContentSize.Width - peekAreaInsets.HorizontalThickness;
groupWidth = NSCollectionLayoutDimension.CreateAbsolute((nfloat)newGroupWidth);
groupHeight = NSCollectionLayoutDimension.CreateFractionalHeight(1);
}

// Each item has a size
var itemSize = NSCollectionLayoutSize.Create(itemWidth, itemHeight);
// Create the item itself from the size
var item = NSCollectionLayoutItem.Create(layoutSize: itemSize);

//item.ContentInsets = new NSDirectionalEdgeInsets(0, itemInset, 0, 0);

var groupSize = NSCollectionLayoutSize.Create(groupWidth, groupHeight);

if (OperatingSystem.IsIOSVersionAtLeast(16))
{
group = isHorizontal
? NSCollectionLayoutGroup.GetHorizontalGroup(groupSize, item, 1)
: NSCollectionLayoutGroup.GetVerticalGroup(groupSize, item, 1);
}
else
{
group = isHorizontal
? NSCollectionLayoutGroup.CreateHorizontal(groupSize, item, 1)
: NSCollectionLayoutGroup.CreateVertical(groupSize, item, 1);
}

var section = NSCollectionLayoutSection.Create(group: group);
section.InterGroupSpacing = itemSpacing;
section.OrthogonalScrollingBehavior = isHorizontal
? UICollectionLayoutSectionOrthogonalScrollingBehavior.GroupPagingCentered
: UICollectionLayoutSectionOrthogonalScrollingBehavior.None;

section.VisibleItemsInvalidationHandler = (items, offset, env) =>
{
if (!weakItemsView.TryGetTarget(out var itemsView) || !weakController.TryGetTarget(out var cv2Controller))
{
return;
}

var page = (offset.X + sectionMargin) / env.Container.ContentSize.Width;

if (Math.Abs(page % 1) > (double.Epsilon * 100) || cv2Controller.ItemsSource.ItemCount <= 0)
{
return;
}

var pageIndex = (int)page;
var carouselPosition = pageIndex;

if (itemsView.Loop && cv2Controller.ItemsSource is ILoopItemsViewSource loopSource)
{
var maxIndex = loopSource.LoopCount - 1;

//To mimic looping, we needed to modify the ItemSource and inserted a new item at the beginning and at the end
if (pageIndex == maxIndex)
{
//When at last item, we need to change to 2nd item, so we can scroll right or left
pageIndex = 1;
}
else if (pageIndex == 0)
{
//When at first item, need to change to one before last, so we can scroll right or left
pageIndex = maxIndex - 1;
}

//since we added one item at the beginning of our ItemSource, we need to subtract one
carouselPosition = pageIndex - 1;

if (itemsView.Position != carouselPosition)
{
//If we are updating the ItemsSource, we don't want to scroll the CollectionView
if (cv2Controller.IsUpdating())
{
return;
}

var goToIndexPath = cv2Controller.GetScrollToIndexPath(carouselPosition);

//This will move the carousel to fake the loop
cv2Controller.CollectionView.ScrollToItem(
NSIndexPath.FromItemSection(pageIndex, 0),
UICollectionViewScrollPosition.Left,
false);
}
}

//Update the CarouselView position
cv2Controller?.SetPosition(carouselPosition);
};

return section;
});

return layout;
}
#nullable enable
class CustomUICollectionViewCompositionalLayout : UICollectionViewCompositionalLayout
{
LayoutSnapInfo _snapInfo;
Expand Down
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