Error: Initializer 'Init(_:)' Requires That 'Binding<String>' Conform to 'Stringprotocol'

Error: Initializer 'init(_:)' requires that 'BindingString' conform to 'StringProtocol'

Use the @Published property wrapper in your Service class, rather than didChange, and iterate over the indices of service.items like so:

struct Item: Identifiable {
    var id: String
    var label: String
    var isOn: Bool {
        didSet {
            // Added to show that state is being modified
            print("\(label) just toggled")
        }
    }
}

class Service: ObservableObject {
    @Published var items: [Item]

    init() {
        self.items = [
            Item(id: "0", label: "Zero", isOn: false),
            Item(id: "1", label: "One", isOn: true),
            Item(id: "2", label: "Two", isOn: false)
        ]
    }
}

struct MyView: View {
    @ObservedObject var service: Service

    var body: some View {
        List {
            ForEach(service.items.indices, id: \.self) { index in
                Section(header: Text(self.service.items[index].label)) {
                    Toggle(isOn: self.$service.items[index].isOn) {
                        Text("isOn")
                    }
                }
            }
        }
        .listStyle(GroupedListStyle())
    }
}

Update: Why use indices?

In this example, we need to get two things from each Item in the model:

1. The String value of the label property, to use in a Text view.
2. A Binding<Bool> from the isOn property, to use in a Toggle view.

(See this answer where I explain Binding.)

We could get the label value by iterating over the items directly:

ForEach(service.items) { (item: Item) in
    Section(header: Text(item.label)) {
    ...
}

But the Item struct does not contain a binding. If you tried to reference Toggle(isOn: item.$isOn), you'd get an error: "Value of type 'Item' has no member '$isOn'."

Instead, the Binding is provided at the top level by the @ObservedObject property wrapper, meaning the $ has to come before service. But if we're starting from service, we'll need an index (and we cannot declare intermediate variables inside the ForEach struct, so we'll have to compute it inline):

ForEach(service.items) { (item: Item) in
    Section(header: Text(item.label)) {
        Toggle(isOn: self.$service.items[self.service.items.firstIndex(of: item)!].isOn) {
        // This computes the index       ^--------------------------------------^
            Text("isOn")
        }
    }
}

Oh, and that comparison to find the index would mean Item has to conform to Equatable. And, most importantly, because we are looping over all items in the ForEach, and then again in the .firstIndex(of:), we have transformed our code from O(n) complexity to O(n^2), meaning it will run much more slowly when we have a large number of Items in the array.

So we just use the indices. Just for good measure,

ForEach(service.items.indices, id: \.self) { index in

is equivalent to

ForEach(0..<service.items.count, id: \.self) { index in

Initializer 'init(_:)' requires that 'BindingString' conform to 'StringProtocol' SwiftUI Text

Text displays an immutable String, hence it's initialiser takes a String, not a Binding<String>.

So inject the String, not a Binding to it.

Text(state.resultString)

Moreover, @State should only be used on Views. resultString should be @Published, not @State.

@EnvironmentObject Initializer 'init(_:)' requires that 'BindingString' conform to 'StringProtocol'

Text takes in a String not a Binding<String>. Replace the line you pointed out with the following:

Text(storage.buttonTitle)

Initializer 'init(_:)' requires that '' conform to 'StringProtocol' SwiftUI Picker with Firebase

You may try the following:

struct SchoolDetailsView: View {
    @ObservedObject var schoolData = getSchoolData() // make `@ObservedObject`/`@StateObject` instead of const array
    @State var selectedSchool = "" // `schoolName.id` is of type String

    var body: some View {
        VStack {
            Form {
                Section {
                    Picker(selection: $selectedSchool, label: Text("School Name")) {
                        ForEach(schoolData.datas, id: \.id) { // choose whether you want to tag by `id` or by `name`
                            Text($0.name)
                        }
                    }
                    Text("Selected School: \(selectedSchool)")
                }
            }.navigationBarTitle("Select your school")
        }
    }
}

Initializer 'init(_:)' requires that 'OneCall.HourlyResponse' conform to 'StringProtocol'

Your weather instance is of type OneCall.

When you use weather.hourly, it is of type OneCall.HourlyResponse, which is obviously doesn't conform to StringProtocol.

weather.hourly.hourly is your string property which you need to use.

requires that 'moveView' conform to 'StringProtocol' in swiftui

Your struct is of type 'View' and you are comparing it to a 'String' constant.

You could check the boolean value:

.opacity(moveView(move: $skc.move).move ? 0.1 : 0.8)

But using the expression:

moveView(move: $skc.move)

does not make sense here. You are creating a new view here with the value of the variable.

Better:

.opacity( skc.move ? 0.1 : 0.8)

Referencing operator function '!=' on 'StringProtocol' requires that 'BindingString' conform to 'StringProtocol' swiftui

you only need the "$" dollar sign if you want to use the binding value, it means you want to change the value of it. In your case just use the the variable without the $.

if viewModel.users[indexValue].relationshipLabel != "Choose" {
 ShowView()
} else {
HideView()
}

SwiftUI - Error - Initializer 'init(_:rowContent:)' requires that 'CustomDataModel' conform to 'Identifiable'

Give your type an id and make it identifiable and if you don’t need decidable don’t add it.

struct MyType: Encodable, Identifiable {
  let id = UUID()

  // other properties
}

Using Codable is just shorthand for adding Encodable and Decodable. So if you don’t need both, then just use the one you need.

Does not conform to String protocol SwiftUI Picker View

As E.Coms noted, the solution is to use one of the following:

Text(self.cardController.cards[$0].description)

Text(String(describing: self.cardController.cards[$0]))

Here's an explanation of why you have to do this inside the Text initializer, but not print().

---

Look at the two initializers for Text:

init(verbatim content: String) (docs)

init<S>(_ content: S) where S : StringProtocol (docs)

You must pass either a String or a Substring, the only two types conforming to StringProtocol. In this case, even though your type conforms to CustomStringConvertible, you are still passing a Card.

---

Contrast this with something like the print function:

func print(_ items: Any..., separator: String = " ", terminator: String = "\n") (docs)

Notice that the print function's arguments are denoted by Any, which is explained as

Any can represent an instance of any type at all, including function types.

The print function then converts whatever you passed it to a String:

The textual representation for each item is the same as that obtained by calling String(item).

String has an initializer which takes a type conforming to CustomStringConvertible and returns the description property.

---

So the reason you can write print(Card()) and not Text(Card() is because the print function has an intermediate step through String that can understand your conformance to CustomStringConvertible, but Text does not. If Text allowed you to pass it any type, it would be both more ambiguous ("What is the text representation of this type?" is not necessarily immediately apparent, as it depends on a hierarchical set of protocols), and more work for the SwiftUI system, which is already doing a lot.

---

Related Topics