SwiftUI，如何将值传递给工作表上显示的视图？

Question

我正在尝试将一个值传递给工作表上显示的子视图。初始值设置为“Fred”。单击按钮时，值将更改为“Jane”，然后显示工作表。哎呀！当工作表出现时，值仍然是“Fred”。我做错了什么？

struct ContentView: View {
    @State private var firstName = "Fred"
    @State private var presentSheet = false
    var body: some View {
        Button {
            firstName = "Jane"
            presentSheet.toggle()
        } label: {
            Text("go to sheet")
        }
        .sheet(isPresented: $presentSheet) {
            SubView(theName: firstName)
                .presentationDetents([.medium])
        }
    }
}

struct SubView: View {
    let theName: String
    var body: some View {
        Text("theName = \(theName)")
    }
}

Answer 1

尝试将

theName

设置为

@Binding

值。不然不会更新

@Binding var theName: String