Using an inputted string as a default text appearing in SwiftUI's TextField

Question

This is a simple struct involving TextField which works fine.

struct NewProjectView: View {
    @State var name = ""
    @State var lastName = ""

    var body: some View {
        VStack{
            TextField("Name: ", text: $name)
            TextField("Last Name: ", text: $lastName)
        }
    }
}

Now, I have modified the struct to accept two parameters, and trying to make them equal to the @State variables.

struct NewProjectView: View {
    var oldName: String
    var oldLastName: String        

    @State var name = oldName // ERROR
    @State var lastName = oldLastName // ERROR

    var body: some View {
        VStack{
            TextField("Name: ", text: $name)
            TextField("Last Name: ", text: $lastName)
        }
    }
}

struct NewProjectView_Previews: PreviewProvider {
    static var previews: some View {
        NewProjectView(oldName: "James", oldLastName: "Morton")
    }
}

However, error appears as follow

Cannot use instance member 'oldName' within property initializer; property initializers run before 'self' is available

The I put self. in front of oldName and oldLastName , another appears,

Use of unresolved identifier 'self'

At this point I have no idea what to do. I expect name and last name to be shown in both TextField s.

Answer 1

If this view is intended to change name and last name then you need @Binding , not a @State

Like in

struct NewProjectView: View {
    @Binding var name: String
    @Binding var lastName: String

    var body: some View {
        VStack{
            TextField("Name: ", text: $name)
            TextField("Last Name: ", text: $lastName)
        }
    }
}

so creating it you can pass into old name and last name, say from some model.