🔸published value

SwiftUI ⟩ view ⟩ state ⟩ observable object ⟩ published value

In an observable object, a property declared by adding @Published property wrapper that notifies all observers when its value is about to change. When the value changes, SwiftUI updates all views that use its data. Also called a published property.

// ⭐️ 1. declare an observable object type
class CreatureZoo : ObservableObject {

    // ⭐️ 2. declare published value(s)
    @Published var creatures = [
        Creature(name: "Gorilla", emoji: "🦍"),    // `Creature` is a custom type
        Creature(name: "Peacock", emoji: "🦚"),
    ]
    
}

// content view
struct ContentView: View {

    // ⭐️ 3. initialize an observable object
    @StateObject var data = CreatureZoo()
    
    var body: some View {
        // ⭐️ 4. access `data.creatures` in subviews
    }
}

👥 相關

• ObservableObject：declare an observable object type.

• @Published：declare a published value in an observable object type.

• @StateObject：initialize an observable object.

📘 手冊