I'm trying to create custom cells with UIStackView and UICollectionViewListCell. The layout is simple. The stack view's edges are pinned to content view's layout margins guide. The stack view's axis is .horizontal The stack view's alignment is .center The stack view has only one arranged subview (a text label). There are two ways to implement such cells: Traditional Cell Subclass UICollectionViewCell or UICollectionViewListCell and layout views in it's contentView property directly. However, stackView.alignment = .center case the stack view renders in wrong size. It's height a bit larger that it's content. If I add a second view to the stack view, for example an empty UIView, the layout works again. New Content Configuration API Use UIContentView and UIContentConfiguration to create a custom content view. However, with stackView.alignment = .center, the app crashes. Thread 1: "Content view returned an invalid size {353, 1.7976931348623157e+308} from -systemLayoutSizeFittingSize:withHorizontalFittingPriority:verticalFittingPriority: which is not allowed. If you have implemented a custom content view, you need to add constraints inside it so that its size is not ambiguous, or you need to manually compute and return a valid size. Content view: <Test.TextLabelContentView: 0x143f0e8a0; frame = (0 0; 353 44); gestureRecognizers = <NSArray: 0x600000f9edc0>; layer = <CALayer: 0x6000001d3d40>>" HomeViewController.swift If I add a second view to the stack view, for example an empty UIView, the layout works again and the app does not crash. Reproduce You can reproduce this problem with the attachment HomeViewController.swift How does UIStackView determine it's size We create a horizontal stack view whose alignment is center. When it has only one arranged subview, the stack view can't determine it's own height. If such a stackview is in a UIContentView, the app will crash. If it's in a tranditional subclass cell, the stackview's height is incorrect (a bit larger than it's content). If such a stackview has more than one arranged subvies, everything works great. Is this expected? let stackView = UIStackView() stackView.axis = .horizontal stackView.alignment = .center The behavior of cell's systemLayoutSizeFitting The app crashes because systemLayoutSizeFitting(_:withHorizontalFittingPriority:verticalFittingPriority:) returns an invalid value. Then I override this method in the cell and find that the targetSize parameter passed to this method is (353.0, 1.7976931348623157e+308). The height is 1.7976931348623157e+308, but why? It looks strange to me. I thought the value should be UIView.layoutFittingCompressedSize.height. override func systemLayoutSizeFitting(_ targetSize: CGSize, withHorizontalFittingPriority horizontalFittingPriority: UILayoutPriority, verticalFittingPriority: UILayoutPriority) -> CGSize { // `targetSize` is (353.0, 1.7976931348623157e+308)     return super.systemLayoutSizeFitting(targetSize, withHorizontalFittingPriority: horizontalFittingPriority, verticalFittingPriority: verticalFittingPriority)   }

There is a new feature about asset catalogs in Xcode 12 Release Notes: Added support for Scalable Vector Graphic (SVG) image assets. These preserve their vector representation with deployment targets of macOS 10.15 or later, iOS 13 or later, and iPadOS 13 or later. (18389814) However, the compatibility about SVG support is a little ambiguous. If we keep Preserve Vector Data option unchecked in Xcode, Can we use these SVG files on iOS 11 ?

The Translation API introduced at Session 10117 is impressive, but limiting it to SwiftUI is restrictive. This API works great in the demo, but for more complex apps, it lacks flexibility because it is bound to SwiftUI Views. Please consider making it available in non-SwiftUI environments.