struct ContentView2: View { @ObservedObject private var counter: Counter = .shared var body: some View { print("ContentView2.body") return VStack { HStack { Text("\(counter.count)") Button("+") { self.counter.increment() } } AView() .padding() .border(Color.gray, width: 1) .padding() } } } private struct AView: View { var body: some View { print("AView.body") return VStack { HStack { Text("\(Counter.shared.count)") Button("+") { Counter.shared.increment() } } BView() .padding() .border(Color.gray, width: 1) .padding() } } } private struct BView: View { var body: some View { print("BView.body") return HStack { Text("\(Counter.shared.count)") Button("+") { Counter.shared.increment() } } } } private final class Counter: ObservableObject { @Published private(set) var count: Int = 0 func increment() { count += 1 } static let shared: Counter = .init() }

↑これだと同一画面だけど AView や BView は更新されない（ iOS 13 ）。おもしろい。 (edited)