SwiftUI - How to append and display nested JSON Data

Question

I am playing with the Instagram API and I encounter the following issue: I managed to decode and access the JSON data but when I try to access a certain value inside a SwiftUI View I encounter the following error: Thread 1: Fatal error: Index out of range. I am totally aware that this is triggered by the fact that the API load is asynchronous but I can not find a fix for this.

I would greatly appreciate your help

Below you can find the API response

Here you can find my model and JSON Decoder

struct InstaAPI: Codable {

    var name: String
    var period: String
    var description: String
    var values: [ValueResponse]
}

struct ValueResponse: Codable {
    let value: String
}

struct Entry: Codable {
    let data: [InstaAPI]
}

class getData: ObservableObject {

@Published var response = [Entry]()

init() {

    downloadJSON(from: URL(string: "https://graph.facebook.com/v6.0/17841402116620153/insights?metric=impressions&period=day&access_token=accounttoken")!)
}

func downloadJSON(from url: URL) {

    URLSession.shared.dataTask(with: url) { data, response, error in

        if let data = data {

            let jsonDecoder = JSONDecoder()

            do {

                let parsedJson = try jsonDecoder.decode(Entry.self, from: data)

                DispatchQueue.main.async {

                    self.response.append(parsedJson)
                }

                for data in parsedJson.data {

                    print(data.values[0].value)
                }

            } catch {
                print(error)
            }
        }

    }.resume()
}
}

workingdog support Ukraine · Accepted Answer · 2020-04-14 02:52:07Z

1

maybe the old fashioned if would do the trick:

struct ContentView: View {
@ObservedObject var response = getData()
@State var responseNdx = 0
@State var dataNdx = 0

var body: some View {
    VStack {
        if responseNdx < self.response.response.count {
            if dataNdx < self.response.response[responseNdx].data.count {
                Text(self.response.response[responseNdx].data[dataNdx].name)
            }
        }
    }
}
}

answered Apr 14, 2020 at 2:52

workingdog support Ukraine

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1 Comment

Catalin Olaru Over a year ago

This worked like a charm! Thank you very much! I really appreciate your time and help

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