import SwiftUI struct UserSettings { var fontSize: CGFloat = 17 } struct UserView: View { @EnvironmentObject var userSettings: UserSettings var body: some View { VStack { Text("Hello, World") .font(.system(size: userSettings.fontSize)) Slider(value: $userSettings.fontSize, in: 10...30) } } } struct ContentView: View { var body: some View { UserView().environmentObject(UserSettings()) } }