Json parsing does not recognize struct

App Development
1

I am working on Swift Foundations UI: Mod 5, lesson 3. We are creating a learning app with a .json file containing a variety of data. So far we have created a struct called Module, and a ContentView with a function to parse the .json data. I have written the parsing code exactly as Chris showed in the lesson. Here’s the code:

class ContentModel: ObservableObject {

@Published var modules = [Module]()

init() {
    getLocalData()
}

func getLocalData() {
    //get a url to json file
    let jsonUrl = Bundle.main.url(forResource: "data", withExtension: "json")
    //read the file into a data object
    do {
        let jsonData = try Data(contentsOf: jsonUrl!)
        let jsonDecoder = JSONDecoder()
   
        **let modules = try jsonDecoder.decode([Module].self, from: jsonData)**
          
        //assign parsed modules to modules property
        self.modules = modules
        }
        catch{
            print("JsonDecoder error")
    }
}

}

The problem: I get a parsing error telling me that “Module” is not a struct. This happens in the line that begins and ends in **. Note: the ** is not in the actual code. I have tried cleaning the build folder and restarting Xcode to no avail.

My questions are: Since I have created a struct called Module, why does the parsing function not recognize it? How can I fix this? (Note: Chris does not have this error in his example.)

As always, your helps is valued and appreciated.

2

And your Module struct conforms to either Decodable or Codable?

Can you post your Module struct code?

3

Rooster :rooster:, here are the structs we created. They are all Decodable and Identifiable as per the lesson. I have checked for typos etc., but don’t see any. As always another set of eyes is appreciated. Thanks for taking the time to look at this.

Personally, I think Xcode is schizophrenic! :thinking:

struct Module: Decodable, Identifiable {
var id: Int
var category: String
var content: Content
var test: Test
}

struct Content: Decodable, Identifiable {
var id: Int
var image: String
var time: String
var description: String
var lessons: [Lesson]
}

struct Lesson: Decodable, Identifiable {
var id: Int
var title: String
var video: String
var duration: String
var explanation: String
}

struct Test: Decodable, Identifiable {
var id: Int
var image: String
var time: String
var description: String
var question: Question
}

struct Question: Decodable, Identifiable {
var id: Int
var content: String
var correctIndex: Int
var answers: [String]
}

4

Missing [ ] at
var content: [Content]

5

Thanks Sparrow :dove:, I’ll fix that and see what happens.

6

Well I added the brackets and still got the parsing error statement. I checked Chris’ code again and found he did not have any brackets in the variables under Module.

Here’s what Chris had:
// Created by Christopher Ching on 2021-03-04.
//

import Foundation

struct Module: Decodable, Identifiable {

var id: Int
var category: String
var content: Content
var test: Test

}

So I copied and pasted his parsing code into my project and now it works, even though the code was (as far as I can tell) exactly the same as what I had. This is why I think Xcode is schizophrenic or maybe has multiple personalities.

Anyway, your suggestion was totally valid. Thanks for trying to help. Everything works right now.

1 Like