How to read and display a dictionary from JSON?

July 22, 2022

I am working on an app that fetches the data from JSON and displays it.
However, I am stuck with an error saying Instance method 'appendInterpolation(_:formatter:)' requires that '[String : Int]' inherit from 'NSObject'

Here is my data structure:

struct Data: Codable {
    var message: String
    var data: Objects
}

struct Objects: Codable {
    var date: String
    var day: Int
    var resource: String
    var stats, increase: [String: Int]
}

Function to fetch the data:

func getData() {
    let urlString = "https://russianwarship.rip/api/v1/statistics/latest"
    let url = URL(string: urlString)
    
    URLSession.shared.dataTask(with: url!) { data, _, error in
        if let data = data {
            do {
                let decoder = JSONDecoder()
                let decodedData = try decoder.decode(Data.self, from: data)
                self.data = decodedData
            } catch {
                print("Hey there's an error: \(error.localizedDescription)")
            }
        }
    }.resume()
}

And a ContentView with the @State property to pass the placeholder data:

struct ContentView: View {

@State var data = Data(message: "", data: Objects(date: "123", day: 123, resource: "", stats: ["123" : 1], increase: ["123" : 1]))


var body: some View {
    VStack {
        Button("refresh") { getData() }
        Text("\(data.data.date)")
        
        Text("\(data.data.day)")
        
        Text(data.message) 
        
        Text("\(data.data.stats)") //error is here

Here is an example of JSON response

I wonder if the problem is in data structure, because both

Text("\(data.data.date)")            
Text("\(data.data.day)")

are working just fine. If there are any workarounds with this issue – please, I would highly appreciate your help!:)

>Solution :

stats is [String: Int], and so when you want to use it, you need to supply the key to get the value Int, the result is an optional that you must unwrap or supply a default value in Text

So use this: