Interview guides / ios

SwiftUI state ownership: iOS Interview Question

SwiftUI state ownership interview question with a clear example answer for iOS engineers. Practice with AceMobileInterview.

This is a common iOS interview topic: SwiftUI state ownership.

Below is a concise answer you can adapt in a real interview, then go deeper in the full AceMobileInterview track.

1. 1.When do you use @State, @Binding, @StateObject, @ObservedObject, and @EnvironmentObject?

   @State owns simple local view state. @Binding reads/writes parent-owned state. @StateObject creates and owns an ObservableObject for the view’s lifetime. @ObservedObject observes an object owned elsewhere (don’t create it inline). @EnvironmentObject shares dependencies down the tree. Prefer @Observable (Observation framework) in modern apps where available.