I am trying to parse some json but seem to be getting nil in the outputs.
I am not sure where I am going wrong and could use some help trying to figure this out.
struct albumInfo: Decodable {
var name: String?
var artist: String?
var url: String?
var playcount: String?
var listeners: String?
var releasedate: String?
var summary: String?
}
class SearchVC: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
Choice = "album"
Album = "Believe"
Artist = "Cher"
let tryURL = "\(BASE_URL)\(Choice!).getinfo&api_key=\(API_KEY)&artist=\(Artist!)&album=\(Album!)&format=json"
print(tryURL)
guard let url = URL(string: tryURL) else { return }
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data else { return }
do {
let albumDescription = try JSONDecoder().decode(albumInfo.self, from: data)
print(albumDescription.artist)
}catch let jsonErr {
print("Error seroalizing json", jsonErr)
}
}.resume()
}
Here is the data as shown with the tryUrl.
First of all please conform to the naming convention that struct names start with a capital letter.
There are two major issues:
album
containing the dictionary with keys name
, listeners
etc.summary
is in another dictionary for key wiki
. The structure of the JSON is very easy to identify. The body within each pair of braces ( {}
) represents a separate struct.
Further there is no key releasedate
so this struct member has to be declared as optional, all other members can be declared as non-optional and as constants ( let
). url
can be declared as URL
for free.
Change your structs to
struct Root : Decodable {
let album : AlbumInfo
}
struct AlbumInfo: Decodable {
let name: String
let artist: String
let url: URL
let playcount: String
let listeners: String
let releasedate: String?
let wiki : Wiki
}
struct Wiki: Decodable {
let content: String
let published: String
let summary: String
}
and decode Root
let albumDescription = try JSONDecoder().decode(Root.self, from: data)
print(albumDescription.album.artist)
您响应的第一个键是“相册”,您需要先解析它。
The classes do not correspond to json, I guess you should use the following approach (new classes implement your decode, encode protocol):
class JsonInfo {
var album : albumInfo
}
do {
let albumDescription = try JSONDecoder().decode(albumInfo.self, from: data)
print(albumDescription.album.artist)
}catch let jsonErr {
print("Error seroalizing json", jsonErr)
}
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