I'm just getting started in iOS development as a hobby, but what does this mean? Can I now build my app in Xcode with an Android target and use that binary in the Play Store? It surely can't be that easy now is it?
> Can I now build my app in Xcode with an Android target and use that binary in the Play Store?
No. The vision document[1] lays out the direction of travel. Currently the focus is on shared business logic and libraries, rather than full native applications (although that's certainly a goal, albeit a very long term one).
The SDK doesn't quite work that way, your iOS-specific dependencies like SwiftUI and UIKit aren't available. For SwiftUI development, [Skip](https://skip.tools/) has a transpiler that translates your SwiftUI code into Jetpack Compose.
Without Skip, you can still share other code through JNI - similar to Kotlin Multiplatform.
Not yet, and possibly not ever quite from Xcode. But using Swift CLI tools, yes.
The example Activty I saw is pretty rough ergonomically, but I have no doubt an ergonomic, SwiftUI-like library could be built on top of what’s currently there and/or on the roadmap.