SwiftUI Binding Error: Why does this not work?

Question

I am facing issues setting up Binding in the following SwiftUI code snippet. I am trying this on xCode Beta 7 ((11M392r).

In the code snippet below, I am creating 2 Stepper views.

If I pass $student.totalMarks to Stepper, it works and creates the right Binding.

But if I try to access $student.marks.score1, that does not work and shows the following compilation error:

Generic parameter 'Subject' could not be inferred.

Is there a way to pass single field from a nested property into a binding?

struct Marks {
    public let score1: Int
    public let score2: Int
    public let score3: Int
}

class Student: ObservableObject {
    @Published var totalMarks: Int = 145
    @Published var marks = Marks(score1: 67, score2: 56, score3: 64)
}

struct ContentView: View {
    @ObservedObject var student = Student()

    var body: some View {
        return VStack {
            Stepper("Total Score: \(student.totalMarks)", value: $student.totalMarks)
            Stepper("Score 1: \(student.marks.score1)", value: $student.marks.score1)
        }
    }
}

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

Maki · Accepted Answer · 2019-09-06 18:00:27Z

1

Easy. ;-) Don't use a constant for a stepper's value binding. Rather make your scores variables (using var instead of let in struct Marks).

answered Sep 6, 2019 at 18:00

Maki

4893 silver badges7 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

SwiftUI Binding Error: Why does this not work?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related