URLSession的Data任务在我尝试使对象符合Identifiable协议时返回Nil。

huangapple
go评论81阅读模式
英文:

URLSession's Data Task returning Nil when I try to conform the object to Identifiable protocol

问题

I'm trying to run a simple http request to Spotify's api to get the recent played tracks

  1. "https://api.spotify.com/v1/me/player/recently-played?limit=2&before=1676369852305"

Everything works and I do get the result back, but when I add the Identifiable protocol with id variable to my struct objects the decoder fails (nil).
(I want to conform to Identifiable because I need to use the data in a List/ForEach loop

Here's my code

  1. //objects
  2. struct Recent: Codable {   //or Codable, Identifiable
  3.     //let id: UUID?
  4.     let items: [Item]?
  5.     let next: String?
  6.     let limit: Int?
  7.     let href: String?
  8. }
  9. struct Item: Codable {    //or Codable, Identifiable
  10.     // let id: UUID?
  11.     let track: Track?
  12.     let played_at: String?
  13. }
  14. struct Track: Codable {    //or Codable, Identifiable  
  15.     //let id: String?  
  16.     let name: String?
  17.     let popularity: Int?
  18.     let trackNumber: Int?
  19.     let type, uri: String?
  20. }
  23. //function
  24. func getRecentPlayed(miliTime: String) {
  25.         //let miliTime = "1676369852305"
  26.         let urlString = "https://api.spotify.com/v1/me/player/recently-played?limit=10&before=\(miliTime)"
  28.         let url = URL(string: urlString)
  29.       
  30.         let urlSessionConfig = URLSessionConfiguration.default
  31.         urlSessionConfig.httpAdditionalHeaders = ["Authorization": "Bearer \(OAuthToken)"]
  32.         
  33.         let urlSession = URLSession(configuration: urlSessionConfig)
  34.         let sessionTask = urlSession.dataTask(with: url!) { data, response, error in
  35.             
  36.             if (error == nil && data != nil) {
  37.                 let jsondecoder = JSONDecoder()
  38.                 let recentPlayedData = try? jsondecoder.decode(Recent.self, from: data!)
  39.                 print (recentPlayedData)
  40.                 recent = recentPlayedData
  41.             } else {
  42.                 print (error)
  43.             }
  44.         }
  45.         sessionTask.resume()
  46.     }

What I want:
Run the following loop in swiftui but it screams saying

  1. "Referencing initializer on 'ForEach' requires that 'Item' conform to 'Identifiable"
  1. //swiftui
  2. @State var recent: Recent?
  4. if let r = recent {
  5.        NavigationView {
  6.             List {
  7.                  ForEach(r.items!) { item in
  8.                             Text((item.track?.name)!)
  9.                  }
  10.             }
  11.             .navigationTitle("Recently played")
  12.        }
  13. }

Any idea anyone?

英文:

I'm trying to run a simple http request to Spotify's api to get the recent played tracks

  1. "https://api.spotify.com/v1/me/player/recently-played?limit=2&before=1676369852305"

Everything works and I do get the result back, but when I add the Identifiable protocol with id variable to my struct objects the decoder fails (nil).
(I want to conform to Identifiable because I need to use the data in a List/ForEach loop

Here's my code

  1. //objects
  2. struct Recent: Codable {   //or Codable, Identifiable
  3.     //let id: UUID?
  4.     let items: [Item]?
  5.     let next: String?
  6.     let limit: Int?
  7.     let href: String?
  8. }
  9. struct Item: Codable {    //or Codable, Identifiable
  10.     // let id: UUID?
  11.     let track: Track?
  12.     let played_at: String?
  13. }
  14. struct Track: Codable {    //or Codable, Identifiable  
  15.     //let id: String?  
  16.     let name: String?
  17.     let popularity: Int?
  18.     let trackNumber: Int?
  19.     let type, uri: String?
  20. }
  23. //function
  24. func getRecentPlayed(miliTime: String) {
  25.         //let miliTime = "1676369852305"
  26.         let urlString = "https://api.spotify.com/v1/me/player/recently-played?limit=10&before=\(miliTime)"
  28.         let url = URL(string: urlString)
  29.       
  30.         let urlSessionConfig = URLSessionConfiguration.default
  31.         urlSessionConfig.httpAdditionalHeaders = ["Authorization": "Bearer \(OAuthToken)"]
  32.         
  33.         let urlSession = URLSession(configuration: urlSessionConfig)
  34.         let sessionTask = urlSession.dataTask(with: url!) { data, response, error in
  35.             
  36.             if (error == nil && data != nil) {
  37.                 let jsondecoder = JSONDecoder()
  38.                 let recentPlayedData = try? jsondecoder.decode(Recent.self, from: data!)
  39.                 print (recentPlayedData)
  40.                 recent = recentPlayedData
  41.             } else {
  42.                 print (error)
  43.             }
  44.         }
  45.         sessionTask.resume()
  46.     }

What I want:
Run the following loop in swiftui but it screams saying

  1. "Referencing initializer on 'ForEach' requires that 'Item' conform to 'Identifiable"
  1. //swiftui
  2. @State var recent: Recent?
  4. if let r = recent {
  5.        NavigationView {
  6.             List {
  7.                  ForEach(r.items!) { item in
  8.                             Text((item.track?.name)!)
  9.                  }
  10.             }
  11.             .navigationTitle("Recently played")
  12.        }
  13. }

Any idea anyone?

答案1

得分: 1

struct Recent: Codable {
var id: String?{
href
}
let items: [Item]?
let next: String?
let limit: Int?
let href: String?
}
struct Item: Codable, Identifiable {
var id: String?{
track?.id
}
let track: Track?
let played_at: String?
}
struct Track: Codable, Identifiable {
var id: String?{
uri
}
let name: String?
let popularity: Int?
let trackNumber: Int?
let type, uri: String?
}

英文:

You can use what you have that is already unique

  1.     struct Recent: Codable {
  2.         var id: String?{
  3.             href
  4.         }
  5.         let items: [Item]?
  6.         let next: String?
  7.         let limit: Int?
  8.         let href: String?
  9.     }
  10.     struct Item: Codable, Identifiable {
  11.         var id:String?{
  12.             track?.id
  13.         }
  14.         let track: Track?
  15.         let played_at: String?
  16.     }
  17.     struct Track: Codable, Identifiable {    //or Codable, Identifiable
  18.         var id: String?{
  19.             uri
  20.         }
  21.         let name: String?
  22.         let popularity: Int?
  23.         let trackNumber: Int?
  24.         let type, uri: String?
  25.     }

答案2

得分: 0

以下是翻译好的部分：

  1. struct Track: Codable, Identifiable {
  2.     let id = UUID() //或者其他内容，不清楚你的id是什么
  3.     let name: String?
  4.     let popularity: Int?
  5.     let trackNumber: Int?
  6.     let type, uri: String?
  7. }
英文:

It is not possible exactly as you want, I think that the closest thing to what you want is this:

  1. struct Track: Codable, Identifiable{    //or   
  2.     let id = UUID() //or something else, it is not clear what is your id  
  3.     let name: String?
  4.     let popularity: Int?
  5.     let trackNumber: Int?
  6.     let type, uri: String?
  7. }

huangapple
  • 本文由 发表于 2023年2月14日 22:13:58
  • 转载请务必保留本文链接：https://go.coder-hub.com/75449088.html
  • jsondecoder
  • swift
  • swift-protocols
  • swiftui
  • urlsession
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