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Good day, All

So I am learning/practicing Network calls. I came across a video by Paul Hudson where he makes a call to the Itunes API using the same code I am trying to use here. However, I am trying to make a call to the Google Books API. My call (code below) is not working, it (returns a blank screen) I am not sure why. I am of course using variables from the URL I am trying to call/make a request from.

import SwiftUI

struct Response: Codable {
    var results: [Result]
}

struct Result: Codable {
    var id: Int
    var etag: String
}

struct ContentView: View {
    @State private var results = [Result]()
    
    var body: some View {
        List(results, id: \.id) { item in
            VStack(alignment: .leading) {
                Text(item.etag)
            }
        }
        .task {
            await loadData()
            // ????
        }
    }
    
    func loadData() async {
        guard let url = URL(string: "https://www.googleapis.com/books/v1/volumes?q=flowers+inauthor:keyes") else {
            print("Invalid URL")
            return
        }
        do {
            let (data, _) = try await URLSession.shared.data(from: url)
            if let decodedResponse = try? JSONDecoder().decode(Response.self, from: data) {
                results = decodedResponse.results
            }
        } catch {
            print("Invalid data")
        }
    }
}

As previously mentioned, this code was tested using the Itunes API and it worked flawlessly. I am not sure what is causing the issue or what can fix it. I will keep searching and practicing on my end.

Thank you!

JLico
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1 Answers1

0

the reason your are getting a blank screen, is because your Response and Result struct do not match the json data you get from the api. Look carefully at the json data and you will see the difference. Try something like this:

struct Response: Codable {
    let items: [Result]  // <--- here
}

struct Result: Codable, Identifiable {  // <--- here
    var id: String      // <--- here
    var etag: String
}

struct ContentView: View {
    @State private var results = [Result]()
    
    var body: some View {
        List(results) { item in  // <--- here
            VStack(alignment: .leading) {
                Text(item.etag)
            }
        }
        .task {
            await loadData()
        }
    }
    
    func loadData() async {
         guard let url = URL(string: "https://www.googleapis.com/books/v1/volumes?q=flowers+inauthor:keyes") else {
             print("Invalid URL")
             return
         }
         do {
             let (data, _) = try await URLSession.shared.data(from: url)
             if let decodedResponse = try? JSONDecoder().decode(Response.self, from: data) {
                 results = decodedResponse.items  // <--- here
             }
         } catch {
             print("Invalid data")
         }
     }
    
}
workingdog support Ukraine
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  • glad it helped. If you use my code with `Result` as `Identifiable` you do not need the id thing. If this answer helped, please mark it as correct. – workingdog support Ukraine Mar 08 '22 at 03:37
  • THANK YOU!!! I overlooked what you pointed out. – JLico Mar 08 '22 at 03:38
  • Note, instead of hand making the boring part of the structs, copy and paste the json data into https://quicktype.io/ and all your swift code is generated for you without errors. – workingdog support Ukraine Mar 08 '22 at 03:40
  • You are totally right about Identifiable. I marked your answer as CORRECT. I deleted my previous comment when I realize that if the Result was conformed to identifiable that would clear the List requirement. – JLico Mar 08 '22 at 03:41
  • I just took a look at quicktype.io this will definitely come in handy going forward. Thank you for the heads up. – JLico Mar 08 '22 at 03:45