I am trying to display a string in a List in Swift but the next error appears:

Cannot convert value of type '[String?]' to expected argument type 'LocalizedStringKey'

struct EmergencyView: View {
    
    // For loadData Function
    @StateObject private var viewModel = EmergencyViewModel()
    
    // Contains the info of the JSON
    @State var emergencies: [EmergencyNumberModel] = []
    
    var body: some View {
        List(emergencies) { emergency in
            
            if emergency.country.name.isEmpty || emergency.police.all.isEmpty {
                Text("No Country or Phone Number")
            } else {
                
                let telephone = emergency.police.all
                Label(telephone, systemImage: "phone.fill") // <<<<<< ERROR here
                    .font(.headline)
            }
                
        }
        .onAppear {
            if let emer = viewModel.loadData(from: "emergency") {
                emergencies = emer
            }
        }
    }
}

The type [String?] comes from a struct that was generated from a JSON file:

// MARK: - EmergencyNumberModelElement
struct EmergencyNumberModel: Codable, Identifiable {
    let id = UUID()
    let country: Country
    let ambulance: Ambulance
    let fire: Fire
    let police: Ambulance

    enum CodingKeys: String, CodingKey {
        case country = "Country"
        case ambulance = "Ambulance"
        case fire = "Fire"
        case police = "Police"
    }
}

// MARK: - Ambulance
struct Ambulance: Codable {
    let all: [String?] // <<<<< Here is the type
    let gsm: [String]?

    enum CodingKeys: String, CodingKey {
        case all = "All"
        case gsm = "GSM"
    }
}

I tried with:

guard let telephone = emergency.police.all // Error: "Type of expression is ambiguous without more context"

And with Force unwrapping (That didn't go well)

Is there a way to cast the variable?

Sources:

Emergency Number API

CodePudding user response：

Your error stem from having [String?] in the Label, where a Label takes just String/LocalizedStringKey. To fix your error you could do this:

if let telephone = emergency.police.all.compactMap{$0}, let firstNumber = telephone.first {
    Label(firstNumber, systemImage: "phone.fill").font(.headline)
}

If you want all numbers to be displayed, use this:

let telephone = emergency.police.all.compactMap{$0}
ForEach(telephone, id: \.self) { phone in
   Label(phone, systemImage: "phone.fill").font(.headline)
}