@Binding

@Binding은 부모 View의 @State와 같은 값 연결 시켜준다.

예제 소스

import SwiftUI

struct ParentsView: View {

    @State private var isOn = false
    
    var body: some View {
        VStack {
            Toggle("On / Off", isOn: $isOn)
            ChildView(isOn: $isOn)
        }
    }
}

struct ChildView: View {

    @Binding var isOn: Bool
    
    var imageName: String {
        if isOn {
            return "lightbulb.fill"
        } else {
            return "lightbulb"
        }
    }
    
    var imageColor: Color {
        if isOn {
            return Color.yellow
        } else {
            return Color.black
        }
    }
    
    var body: some View {
        Image(systemName: imageName)
            .resizable()
            .frame(width: 50, height: 50, alignment: .center)
            .foregroundColor(imageColor)
            
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            ParentsView()
        }
    }
}