Browse Questions
  • Both run code when a view appears, but task {} is purpose-built for async work.
  • These are three distinct levels of organisation in an Xcode workspace.
  • AsyncStream converts callback or delegate-based event sources into an AsyncSequence you can iterate over with for await.
  • Every UIView has a CALayer that does the actual drawing and compositing.

Answer: Both run code when a view appears, but task {} is purpose-built for async work.

onAppeartask
Async support❌ No✅ Yes
Auto-cancels❌ No✅ Yes (when view disappears)
Retry on id change❌ No✅ With id: parameter

Code Example:

struct ArticleView: View {
    @State private var article: Article?

    var body: some View {
        Text(article?.title ?? "Loading...")
            .task {
                // automatically cancelled if view disappears
                article = await ArticleService.fetch()
            }
    }
}