Getting JSON data out of local scope in SWIFT 4

Question

So, I have been trying to make this code work for a couple of days and I don't know what I am doing wrong.

I am getting a JSON from the web and parsing it with Struct blocks.

The question is: I want to use the Dictionaries and Array from the JSON out of where I created de decode function.

Here is the code

import UIKit


struct  Currency_format: Decodable{
    var iso_code: String
    var example_format : String
    var decimal_digits : Int
    var decimal_separator : String
    var symbol_first : Bool
    var group_separator : String
    var currency_symbol : String
    var display_symbol : Bool
}

struct  Date_Format: Decodable{
    var format : String
}

struct Budgets: Decodable {
    var id : String
    var name: String
    var last_modified_on : String
    var first_month : String
    var last_month : String
    var date_format : Date_Format
    var currency_format : Currency_format
}

struct DataResponse : Decodable {
    var data : Data
}

struct Data : Decodable{
    var budgets : [Budgets]
}


class ViewController: UIViewController {


override func viewDidLoad() {
    super.viewDidLoad()
    let accessToken = "1234"
    let authorizationRequestHeader = "https://www.somewhere.com=\(accessToken)"


    guard let url = URL(string: authorizationRequestHeader) else {
        print("Error")
        return
    }
    let session = URLSession.shared
    session.dataTask(with: url) { (stringData, response, Error) in
        let testString =  try! dataResponse.decode(DataResponse.self, from:stringData!)
        print("Number of records: \(testString.data.budgets.count)")
        //THIS PRINT WORKS AS I WANT IT TO WORK. NOT PROBLEM HERE
        }.resume()

  print("Number of records: \(testString.data.budgets.count)") // BUT THE SAME CODE HERE, DOES NOT WORK AT ALL

Use a property instead of a local variable. – rmaddy Jul 13 '18 at 03:50 — rmaddy, Jul 13 '18 at 03:50

score 0 · Accepted Answer · answered Jul 13 '18 at 04:08

0

Do one thing, initialize testString just before the viewDidLoad() Like :

class ViewController: UIViewController {

let testString : DataResponse!

override func viewDidLoad() {
super.viewDidLoad()
    let accessToken = "1234"
    let authorizationRequestHeader = "https://www.somewhere.com=\(accessToken)"


    guard let url = URL(string: authorizationRequestHeader) else {
        print("Error")
        return
    }
    let session = URLSession.shared
    session.dataTask(with: url) { (stringData, response, Error) in
        testString =  try! dataResponse.decode(DataResponse.self, from:stringData!)
        print("Number of records: \(testString.data.budgets.count)")

    }.resume()


print("Number of records: \(testString.data.budgets.count)")
}

Hope this is helpful.

answered Jul 13 '18 at 04:08

JAINESH DOSHI

250
2
13

The last `print` will still fail as it does in the original code. But that is simply because it's being called long before the data is ready. – rmaddy Jul 13 '18 at 15:42
Yeah, it worked but I needed to twike a little: self.testString = try! JSONDecoder().decode(DataResponse.self, from:stringData!) – Thiago Gonçalves Pinto Jul 13 '18 at 15:47
@ThiagoGonçalvesPinto Because your data is loaded asynchronously in the background via `URLSession`. Meanwhile, the result of the code in `viewDidLoad` keeps going and that last `print` is called long before the data is retrieved from the URL. – rmaddy Jul 13 '18 at 22:44

score 0 · Answer 2 · answered Jul 13 '18 at 07:09

0

JSON Decoder method does not work normally with snake_case keys available in your JSON. To work as excepted, in this case we have to use CodingKeys methodology.

Refer this documentation for detailed info.

answered Jul 13 '18 at 07:09

Prasath R

79
3

Sample Example: struct Item : Decodable { let title:String,content:String,version:Int,created:Int32,modified:Int32,noteId:Int private enum CodingKeys : String, CodingKey { case title,content,version,created,modified,noteId = "note_id" } } // Inside response completion do { let items = try JSONDecoder().decode([Item].self, from: data) print(items) } catch { print(error) } – Prasath R Jul 13 '18 at 07:16

Getting JSON data out of local scope in SWIFT 4

2 Answers2