Swift 4 download Swedens radio channels - json

Question

I got the same error when I try to get previous and song that play right now for every channel. I think something is wrong in my struct Root and playlist because data is not in the correct format.I am using Swift 4 and trying to learn JSON, but its hard. Previous struct is same as Song struct.
How do I fix my error?
My code looks now:
*struct Root : Decodable {
let copyright : String
let channels : [Channel]
let pagination : Pagination
//let playlists : [Playlist]
}
struct Channel : Decodable {
let image : String
let imagetemplate : String
let color : String
let tagline : String?
let siteurl : String
let id : Int
let url : URL?
let statkey : String?
let scheduleurl : String
let channeltype : String
let name : String
}
struct Pagination : Decodable {
let page, size, totalhits, totalpages : Int
let nextpage : URL
}
struct Playlist : Decodable{
let id : Int
let name :String
let prev : [previoussong]
let song : [Song]
}
struct Song : Decodable {
let title : String
let description : String
let artist : String
let composer :String
let conductor : String
let albumname : String
let recordlabel : String
let lyricist : String
let producer : String
let starttimeutc : String
let stopttimeutc : String
}
var tests = [Channel]()
var pl = [Playlist]()
func downloadStations(){
let test2 = "http://api.sr.se/api/v2/channels?format=json"
let play = "http://api.sr.se/api/v2/playlists/rightnow?format=json"
let url = URL(string: test2) /// play instead of test2
URLSession.shared.dataTask(with: url!){ (data , response, error) in
do{
let root = try JSONDecoder().decode(Root.self, from: data!)
self.tests = root.channels
//self.pl = root.playlists
for eachStations in self.tests {
DispatchQueue.main.async {
self.tableV.reloadData()
}
}
} catch {
print(error.localizedDescription)
}
}.resume()*

Answer 1

It doesn't return the array of channels. It returns an object:
{
"copyright": "somestring",
"pagination": {},
"channels": []
}
So, copyright is not a part of channel and you have an object with field channels.

Answer 2

Please read the JSON carefully. In the root object there is the key copyright and a key channels which contains the channel array.
You need to add an umbrella struct for the root object.
Please name the channel struct in singular form and with starting uppercase letter (Channel). Further some keys in the struct are optional.
struct Root : Decodable {
let copyright : String
let channels : [Channel]
let pagination : Pagination
}
struct Channel : Decodable {
let image : String
let imagetemplate : String
let color : String
let tagline : String?
let siteurl : String
let id : Int
let url : URL?
let statkey : String?
let scheduleurl : String
let channeltype : String
let name : String
}
struct Pagination : Decodable {
let page, size, totalhits, totalpages : Int
let nextpage : URL
}
var tests = [Channel]()
let root = try JSONDecoder().decode(Root.self, from: data!)
self.tests = root.channels

Answer 3

I got the same error when I try to get previous and song that play right now for every channel. How do I fix this?
My code looks now:
struct Root : Decodable {
let copyright : String
let channels : [Channel]
let pagination : Pagination
//let playlists : [Playlist]
}
struct Channel : Decodable {
let image : String
let imagetemplate : String
let color : String
let tagline : String?
let siteurl : String
let id : Int
let url : URL?
let statkey : String?
let scheduleurl : String
let channeltype : String
let name : String
}
struct Pagination : Decodable {
let page, size, totalhits, totalpages : Int
let nextpage : URL
}
struct Playlist : Decodable{
let id : Int
let name :String
let prev : [previoussong]
let song : [Song]
}
struct previoussong : Decodable {
let title : String
let description : String
let artist : String
let composer :String
let conductor : String
let albumname : String
let recordlabel : String
let lyricist : String
let producer : String
let starttimeutc : String
let stopttimeutc : String
}
struct Song : Decodable {
let title : String
let description : String
let artist : String
let composer :String
let conductor : String
let albumname : String
let recordlabel : String
let lyricist : String
let producer : String
let starttimeutc : String
let stopttimeutc : String
}
var tests = [Channel]()
var pl = [Playlist]()
var stationsName:String?
#IBOutlet weak var tableV: UITableView!
#IBOutlet weak var image: UIImageView!
#IBOutlet weak var statLabel: UILabel!
#IBOutlet weak var songLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
tableV.dataSource = self
downloadStations()
}
func downloadStations(){
let test2 = "http://api.sr.se/api/v2/channels?format=json"
let play = "http://api.sr.se/api/v2/playlists/rightnow?format=json"
let url = URL(string: test2) /// play instead of test2
URLSession.shared.dataTask(with: url!){ (data , response, error) in
do{
let root = try JSONDecoder().decode(Root.self, from: data!)
self.tests = root.channels
//self.pl = root.playlists
for eachStations in self.tests {
self.stationsName = eachStations.name
print(" " + self.stationsName!)
DispatchQueue.main.async {
self.tableV.reloadData()
}
}
} catch {
print(error.localizedDescription)
}
}.resume()