Following on from my previous post on this topic I found a forum post with someone struggling to build a calculator using @Observable and thought maybe my technique of wrapping withObservationTracking in AsyncStream might help and came up with the code below which appears to work. Obviously this code comes Read more…
I needed to create an AsyncStream to monitor changes to an @Observable model class’s var and by using withCheckedContinuation and AsyncStream‘s unfolding init I came up with this: The challenge here is withObservationTracking only watches for a single change but we can wrap that in withCheckedContinuation which also is designed Read more…
I noticed a snag when using NavigationLink(value:label:) and .navigationDestination(for:destination:) with the new @Observable vs the old Combine ObservableObject (which “just worked™️”). There are 2 compilation errors: Fortunately it is relatively simple to add Hashable conformance to an @Observable class by implementing a static func == and a func hash that Read more…
In SwiftIUI, when requiring the reference semantics of a class and wanting to upgrade from Combine’s ObservableObject and @StateObject to the new @Observable it requires a bit more work to get the life-cycle correct. The reason for this is we have to store the object in @State which is designed Read more…
Today I successfully cloned my M1 MacBook Air to a new M3 MacBook Pro, it took some effort so thought I would share the steps here. Before I begin, the reason I prefer to clone rather than use Migration Assistant is I have many command line tools installed all over Read more…
Sharing @AppStorage without having to pass it into every feature of the app is simply done in the same way it’s done for anything else you want to share: EnvironmentKey. It lets you share a source of truth into a View hierarchy without needing to pass it into every View. Read more…
When I first used AsyncStream with merge from AsyncAlgorithms I struggled with merging different stream result types and had experimented with building a protocol that each stream’s result type enum implemented. That way all the streams used the same protocol type and could be merged. I realised today that I Read more…
A new collapse delegate was added in Xcode 12 and iOS 14. Unfortunately the Master-Detail template was removed so there has never been a good example of how to use it to maintain the behavior of the previous template which was to show the master if no detail is showing. Read more…
Discovered this strange error in Swift, when using the sample code from the proposal which is supposed to have been accepted and implemented
I needed to show an alert in an async context and this is how I achieved it: The idea to throw a cancellation exception was inspired by DDDevicePickerViewController which is the only built-in async UIViewController I’m aware of.