SwiftUI ViewModel 发布的属性和绑定

Question

My question is probably the result of a misunderstanding but I can't figure it out, so here it is:

When using a component like a TextField or any other component requiring a binding as input

TextField(title: StringProtocol, text: Binding<String>)

And a View with a ViewModel, I naturally thought that I could simply pass my ViewModel @Published properties as binding:

class MyViewModel: ObservableObject { 
     @Published var title: String
     @Published var text: String
}

// Now in my view
var body: some View {
    TextField(title: myViewModel.title, text: myViewModel.$text)
}

But I obviously can't since the publisher cannot act as binding. From my understanding, only a @State property can act like that but shouldn't all the @State properties live only in the View and not in the view model? Or could I do something like that:

class MyViewModel: ObservableObject { 
     @Published var title: String
     @State var text: String
}

And if I can't, how can I transfer the information to my ViewModel when my text is updated?

Answer 1

You were almost there. You just have to replace myViewModel.$text with $myViewModel.text .

class MyViewModel: ObservableObject {

    var title: String = "SwiftUI"

    @Published var text: String = ""
}

struct TextFieldView: View {

    @ObservedObject var myViewModel: MyViewModel = MyViewModel()

    var body: some View {
        TextField(myViewModel.title, text: $myViewModel.text)
    }
}