{"id":44202,"date":"2024-07-24T16:15:11","date_gmt":"2024-07-24T20:15:11","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=44202"},"modified":"2025-02-11T16:43:32","modified_gmt":"2025-02-11T21:43:32","slug":"swiftui-at-wwdc24","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2024\/07\/24\/swiftui-at-wwdc24\/","title":{"rendered":"SwiftUI at WWDC24"},"content":{"rendered":"

What’s new in SwiftUI<\/a>:<\/p>\n

Learn how you can use SwiftUI to build great apps for any Apple platform. Explore a fresh new look and feel for tabs and documents on iPadOS. Improve your window management with new windowing APIs, and gain more control over immersive spaces and volumes in your visionOS apps. We’ll also take you through other exciting refinements that help you make expressive charts, customize and layout text, and so much more.<\/p><\/blockquote>\n\n

SwiftUI essentials<\/a>:<\/p>\n

Join us on a tour of SwiftUI, Apple’s declarative user interface framework. Learn essential concepts for building apps in SwiftUI, like views, state variables, and layout. Discover the breadth of APIs for building fully featured experiences and crafting unique custom components. Whether you’re brand new to SwiftUI or an experienced developer, you’ll learn how to take advantage of what SwiftUI has to offer when building great apps.<\/p><\/blockquote>\n\n

Work with windows in SwiftUI<\/a>:<\/p>\n

Learn how to create great single and multi-window apps in visionOS, macOS, and iPadOS. Discover tools that let you programmatically open and close windows, adjust position and size, and even replace one window with another. We’ll also explore design principles for windows that help people use your app within their workflows.<\/p><\/blockquote>\n\n

Tailor macOS windows with SwiftUI<\/a>:<\/p>\n

Make your windows feel tailor-made for macOS. Fine-tune your app’s windows for focused purposes, ease of use, and to express functionality. Use SwiftUI to style window toolbars and backgrounds. Arrange your windows with precision, and make smart decisions about restoration and minimization.<\/p><\/blockquote>\n\n

Demystify SwiftUI containers<\/a>:<\/p>\n

Learn about the capabilities of SwiftUI container views and build a mental model for how subviews are managed by their containers. Leverage new APIs to build your own custom containers, create modifiers to customize container content, and give your containers that extra polish that helps your apps stand out.<\/p><\/blockquote>\n\n

Create custom visual effects with SwiftUI<\/a>:<\/p>\n

Discover how to create stunning visual effects in SwiftUI. Learn to build unique scroll effects, rich color treatments, and custom transitions. We’ll also explore advanced graphic effects using Metal shaders and custom text rendering.<\/p><\/blockquote>\n\n

Catch up on accessibility in SwiftUI<\/a>:<\/p>\n

SwiftUI makes it easy to build amazing experiences that are accessible to everyone. We’ll discover how assistive technologies understand and navigate your app through the rich accessibility elements provided by SwiftUI. We’ll also discuss how you can further customize these experiences by providing more information about your app’s content and interactions by using accessibility modifiers.<\/p><\/blockquote>\n\n

Enhance your UI animations and transitions<\/a>:<\/p>\n

Explore how to adopt the zoom transition in navigation and presentations to increase the sense of continuity in your app, and learn how to animate UIKit views with SwiftUI animations to make it easier to build animations that feel continuous.<\/p><\/blockquote>\n\n

Swift Charts: Vectorized and function plots<\/a>:<\/p>\n

The plot thickens! Learn how to render beautiful charts representing math functions and extensive datasets using function and vectorized plots in your app. Whether you’re looking to display functions common in aerodynamics, magnetism, and higher order field theory, or create large interactive heat maps, Swift Charts has you covered.<\/p><\/blockquote>\n\n

Migrate your TVML app to SwiftUI<\/a>:<\/p>\n

SwiftUI helps you build great apps on all Apple platforms and is the preferred toolkit for bringing your content into the living room with tvOS 18. Learn how to use SwiftUI to create familiar layouts and controls from TVMLKit, and get tips and best practices.<\/p><\/blockquote>\n\n

Fatbobman<\/a>:<\/p>\n

\n

Starting with this version, the SwiftUI development team appears to have found the right path to rapidly evolve SwiftUI, exploring ways to enhance its capabilities while maintaining the characteristics of a declarative framework.<\/p>\n

In this update, the SwiftUI team changed its previous API design strategy—from highly encapsulated and less flexible designs to providing developers with greater lower-level control. This includes integrating UIKit gestures, introducing more functional custom containers, custom rendering of Text and providing precise scroll control. These improvements have significantly raised the upper limits of SwiftUI, opening up broader technical possibilities for advanced developers.<\/p>\n

As SwiftUI shares mechanisms for animations, transitions, and gestures with the UIKit framework, it is gradually transitioning from a framework built on UIKit\/AppKit to a more equal partner within Apple’s UI framework ecosystem. It is no longer just drawing features from other frameworks but is starting to give back by contributing new features to them.<\/p>\n

The new version of the SwiftUI framework also underwent code-level stratification, carving out a separate SwiftUICore framework. This was likely done to facilitate better collaboration with UIKit and AppKit, but it also opens up exciting possibilities for future developments.<\/p>\n<\/blockquote>\n\n

Colin Cornaby<\/a>:<\/p>\n

\n

SwiftUI has usually been thought of as an abstraction layer over AppKit and UIKit. But this WWDC is the first time I get the feeling AppKit and UIKit are becoming abstraction layers over SwiftUI.<\/p>\n<\/blockquote>\n\n

Majid Jabrayilov<\/a>:<\/p>\n

SwiftUI introduced the new overloads for Group<\/code> and ForEach<\/code> views, allowing us to create custom containers like List<\/code> or TabView<\/code>.<\/p>

[…]<\/p>

The new ScrollPosition<\/code> type, in pair with the scrollPosition<\/code> view modifier, allows us to read the precise position of a ScrollView<\/code> instance. We can also use it to programmatically scroll to the particular point of the scrolling content.<\/p>

[…]<\/p>

The new Entry<\/code> macro allows us to quickly introduce environment values, focused values, container values, etc, without boilerplate.<\/p><\/blockquote>\n\n

Paul Hudson<\/a>:<\/p>\n

\n

This is another good year for SwiftUI, with another batch of scrollview improvements, some welcome macOS features, remarkable control over text rendering, and more – the team at Apple have a lot to be proud of, and many developers will breathe a sigh of relief as API such as fine-grained subview control is now public for all of us to use.<\/p>\n

[…]<\/p>\n

The difference is small, but makes a huge difference: the @MainActor<\/code> attribute moved from body<\/code> up to the [View<\/code>] protocol itself, which means the body<\/code> property along with all other properties and methods we make<\/em> are run on the main actor.<\/p>\n<\/blockquote>\n\n

Kyle Howells<\/a>:<\/p>\n

\n

After 5 years SwiftUI ScrollView<\/code> finally gets one of the basic fundamental features<\/a> a ScrollView<\/code> needs.<\/p>\n<\/blockquote>\n\n

Majid Jabrayilov<\/a>:<\/p>\n

\n

This week, we will discuss monitoring scroll phases in SwiftUI.<\/p>\n<\/blockquote>\n\n

Clarko<\/a>:<\/p>\n

\n

The new Entry<\/code> macro being backported is so wonderful.<\/p>\n

Immediately deleted a bunch of boilerplate from EnvironmentValues<\/code> and FocusedValues<\/code>.<\/p>\n<\/blockquote>\n\n

Majid Jabrayilov<\/a>:<\/p>\n

\n

This week, we will talk about the Entry<\/code> macro type.<\/p>\n<\/blockquote>\n\n

Swift Talk<\/a>:<\/p>\n

\n

Today, we want to discuss environment values, preferences, and view updates.<\/p>\n<\/blockquote>\n\n

robb<\/a>:<\/p>\n

There are some real crowd pleasers coming to SwiftUI this year at WWDC2024.<\/p>

Here’s the full list<\/a>, but I’ll call out some personal favorites[…]<\/p>\n

[…]<\/p>\n

Group<\/code> and ForEach<\/code> are getting superpowers this year, including the ability to iterate over and transform the subviews of a view. (No more _VariadicView<\/code> shenanigans!)<\/p><\/blockquote>\n

This seems like the biggest change to me. I will be interested to hear how the performance is.<\/p>\n\n

Matthaus Woolard<\/a>:<\/p>\n

New in macOS 15, we can now use onModifierKeysChanged(mask:initial:_:)<\/a> to update our views when keyboard modifiers are held down.<\/p><\/blockquote>\n\n

Francisco Tolmasky<\/a>:<\/p>\n

“If we just keep saying SwiftUI is the best way to write apps it’ll eventually come true, right?”<\/p><\/blockquote>\n\n

Steve Troughton-Smith<\/a>:<\/p>\n

\n

You can now build AppKit NSMenus<\/code> in SwiftUI with the NSHostingMenu<\/code> API.<\/p>\n<\/blockquote>\n\n

Marcin Krzyzanowski<\/a>:<\/p>\n

\n

I had some hopes that Apple would embrace new Swift concurrency in their API for a Swift 6 launch. I guess not necessarily, if not even modern SwiftUI API got update.<\/p>\n

It’s going fine: @preconcurrency<\/code>, @unchecked Sendable<\/code><\/p>\n<\/blockquote>\n\n

Robb Böhnke<\/a>:<\/p>\n

\n

SwiftUI’s new Color.mix(with:by:)<\/code> API allows you to interpolate Color<\/code>s that match SwiftUI.Gradient<\/code> in discrete steps.<\/p>\n<\/blockquote>\n\n

Khoa<\/a>:<\/p>\n

\n

The new SwiftUI Window<\/code> modifier for macOS is great. There is less need for AppKit now<\/p>\n<\/blockquote>\n\n

Antoine<\/a>:<\/p>\n

I’m DYING to know why can’t SwiftUI just give you the NSWindow<\/code> so we don’t have to wait years for them to add the most basic stuff<\/p><\/blockquote>\n\n

Ron Avitzur<\/a>:<\/p>\n

I submitted FB13821655 June 9, 2024 “Support onboarding View for iOS SwiftUI document-based apps” and received response from Apple June 12, 2024 saying “The API you’re asking for has been released in a new Beta now. Here’s the WWDC session that covers it.<\/p>

This wins both the “Fastest response to a Feedback feature request” and the “Most useful response” awards by a long mile.<\/p><\/blockquote>\n\n

Duncan Babbage<\/a>:<\/p>\n

\n

Would love any leads on this: setting [Core Data] .fetchBatchSize<\/code> causes entire collection to be immediately traversed [by SwiftUI].<\/p>\n<\/blockquote>\n\n

Helge Heß<\/a>:<\/p>\n

\n

Did someone try whether the SwiftUI refresh issue in SwiftData got fixed? Some blog sounded like no?<\/p>\n<\/blockquote>\n\n

Scott Anguish<\/a>:<\/p>\n

\n

Just realized, SwiftUI views still can’t just print. I can’t believe another year went by without that.<\/p>\n<\/blockquote>\n\n

Damien Petrilli<\/a>:<\/p>\n

\n

5y into SwiftUI, still no justify Text<\/code> alignment.<\/p>\n<\/blockquote>\n\n

Natalia Panferova<\/a>:<\/p>\n

For a while, presenting a form sheet in SwiftUI, equivalent to the UIModalPresentationStyle.formSheet<\/a>, was a challenge. Now, with the new presentationSizing()<\/a> modifier, we can easily achieve this using the form<\/a> sizing option.<\/p><\/blockquote>\n\n

Andy Finnell<\/a>:<\/p>\n

\n

I feel like SwiftUI’s Form<\/code> should have been an exemplar of the power and ease-of-use of declarative UI code. It instead its a demonstration of the pitfalls.<\/p>\n

The same code doesn’t adapt correctly across platforms. When layout goes wrong, it’s not clear how to fix it or if it can even be fixed.<\/p>\n<\/blockquote>\n\n

alfamsome2<\/a>:<\/p>\n

\n

I have a simple SwiftUI app that has a picker, textfield and several buttons. It is using a Enum as a focus state for the various controls. When I compile and run it on Mac Studio desktop it works as expected: Picker has initial focus, Selection in Picker changes focus to TextField, Tab key moves through buttons; last button resets to Picker<\/p>\n

However when I run the exact same app on MacBook Pro (same version of MacOS, 14.5) it does not work at all as expected. Instead: Initial focus is set to TextField, Tab does not change the focus, Clicking on last button resets focus to TextField rather than Picker.<\/p>\n<\/blockquote>\n\n

[Update (2024-07-25): It turns out<\/a> that this was due to a different system setting<\/a>.]<\/p>\n\n

Andy Finnell<\/a>:<\/p>\n

\n

Xcode previews would be super-helpful in iterating over Form<\/code>s. However, I also discovered if my SwiftUI View<\/code> uses macros to generate any of its code, previews don’t work at all. Doesn’t matter if I build them old-school or use the #\\Preview<\/code> macro.<\/p>\n

Maybe the new preview system in Xcode 16 fixes this?<\/p>\n<\/blockquote>\n\n

Andy Finnell<\/a>:<\/p>\n

\n

For all of Swift’s rich static typing, SwiftUI doesn’t seem able to leverage it in ways that would make it ergonomic. Everything gets erased to a View<\/code>, effectively. There’s no typing to hint at what View<\/code>s would work in a specific context, or type errors about invalid combinations.<\/p>\n<\/blockquote>\n\n

Ole Begemann<\/a>:<\/p>\n

\n

If you want to go spelunking in SwiftUI’s .swiftinterface<\/tt> file (people have found interesting things in there in past years), note that there’s a new SwiftUICore.framework<\/tt> this year, so now there’s two files to check.<\/p>\n

\/Applications\/Xcode-16.0b1.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/SDKs\/iPhoneOS.sdk\/System\/Library\/Frameworks\/SwiftUICore.framework\/Modules\/SwiftUICore.swiftmodule\/arm64-apple-ios.swiftinterface<\/pre>\n<\/blockquote>\n\n
Marcin Krzyzanowski<\/a>:<\/p>\n
\n
My beef about today’s Swift adoption at Apple is SwiftUI. It is a framework that stands against what Swift promised to developers back in the days<\/p>\n