How to access a variable of an instance of a view in ContentView SwiftUI?

Question

So in ContentView, I've created a view with the following:

ViewName()

I'd like to change a variable in ContentView to the value of a variable in ViewName. I was hoping I could do something like:

ViewName() {
    contentViewVariable = self.variableNameInViewNameInstance
}

but that was just kind of a guess as to how to access the value; it didn't work. Any suggestions would be greatly appreciated!

Answer 1

For whatever reason it is needed technically it is possible to do via callback closure.

Caution: the action in such callback should not lead to refresh sender view, otherwise it would be just either cycle or value lost

Here is a demo of usage & solution. Tested with Xcode 11.4 / iOS 13.4

ViewName { sender in
    print("Use value: \(sender.vm.text)")
}

and

struct ViewName: View {

    @ObservedObject var vm = ViewNameViewModel()

    var callback: ((ViewName) -> Void)? = nil    // << declare

    var body: some View {
        HStack {
            TextField("Enter:", text: $vm.text)
        }.onReceive(vm.$text) { _ in
            if let callback = self.callback {
                callback(self)       // << demo of usage
            }
        }
    }
}

class ViewNameViewModel: ObservableObject {
    @Published var text: String = ""
}