iOS 16 beta 4 is the first SDK release that supports Live Activities. A Live Activity is a widget-like view an app can place on your lock screen and update in real time. Examples where this can be useful include live sports scores or train departure times. These are my notes on playing with the…
SwiftUI’s .task modifier inherits its actor context from the surrounding function. If you call .task inside a view’s body property, the async operation will run on the main actor because View.body is (semi-secretly) annotated with @MainActor. However, if you call .task from a helper property or function that isn’t @MainActor-annotated, the async operation will run…
Mac apps built with Xcode 14.0 and 14.0.1 may contain concurrency bugs because the Swift 5.7 compiler can generate invalid code when targeting the macOS 12.3 SDK. If you distribute Mac apps, you should build them with Xcode 13.4.1 until Xcode 14.1 is released. Here’s what happened: Swift 5.7 implements SE-0338: Clarify the Execution of…
On the positioning of the .animation modifier in the view tree, or: “Rendering” vs. “non-rendering” view modifiers The documentation for SwiftUI’s animation modifier says: Applies the given animation to this view when the specified value changes. This sounds unambiguous to me: it sets the animation for “this view”, i.e. the part of the view tree…
The clipped() modifier in SwiftUI clips a view to its bounds, hiding any out-of-bounds content. But note that clipping doesn’t affect hit testing; the clipped view can still receive taps/clicks outside the visible area. I tested this on iOS 16.1 and macOS 13.0. Example Here’s a 300×300 square, which we then constrain to a 100×100…
I wrote an app called SwiftUI View Lifecycle. The app allows you to observe how different SwiftUI constructs and containers affect a view’s lifecycle, including the lifetime of its state and when onAppear gets called. The code for the app is on GitHub. It can be built for iOS and macOS. The view tree and…
I know I’m almost a decade late to this party, but I’m probably not the only one, so here goes. Double Fine Adventure was a wildly successful 2012 Kickstarter project to crowdfund the development of a point-and-click adventure game and, crucially, to document its development on video. The resulting game Broken Age was eventually released…
“SwiftUI is accessible by default” is one of the most repeated misconceptions in iOS development. Here’s why that’s wrong and what you actually need to watch out for.
SwiftUI previews offer a fast, practical way to see the output of our view code. But did you know you can also use them to test accessibility-related UI changes including Dynamic Type, localisation, and system accessibility settings, all without needing a physical device.
Many high-quality indie apps support dyslexia-friendly fonts as a customisation. Should you follow their lead? Well… probably not.