arrays - 如何在 Swift 4 中选择要反序列化的 JSON 数组

Question

JSON 链接:https://apps.runescape.com/runemetrics/profile/profile?user=Rhidlor

所以基本上我正在使用的 JSON 文件中有 2 个数组，我只想从第二个数组中获取信息。我的问题是如何指定要解码到各自结构中的数组，现在我认为我的代码只是试图解码它遇到的第一个数组，这是有问题的。

(“技能”结构是给我带来问题的结构)

import UIKit

struct User: Decodable {
var rank: String?
var totalxp: Int?
var totalskill: Int?
var combatlevel: Int?
var questscomplete: Int?

init(json: [String: Any]){
    self.rank = json["rank"] as? String
    self.totalxp = json["totalxp"] as? Int
    self.totalskill = json["totalskill"] as? Int
    self.combatlevel = json["combatlevel"] as? Int
    self.questscomplete = json["questscomplete"] as? Int
}
//self.rank = rank
}

struct Skill: Decodable {
var level: Int?
var xp: Int?
var rank: Int?
var id: Int?

init(json: [String: Any]){
    self.level = json["level"] as? Int
    self.xp = json["xp"] as? Int
    self.rank = json["rank"] as? Int
    self.id = json["id"] as? Int
}

}

class ViewController: UIViewController {

@IBOutlet var greetingLabel: UILabel!
@IBOutlet var rankLabel: UILabel!
@IBOutlet var totalxpLabel: UILabel!
@IBOutlet var totalskillLabel: UILabel!
@IBOutlet var combatlevelLabel: UILabel!
@IBOutlet var questscompleteLabel: UILabel!

var username: String?

@IBAction func usernameTextField(_ sender: UITextField) {
    username = sender.text!
    parseJson(username: username!)
}

override func viewDidLoad() {
    super.viewDidLoad()

}

func setValues(rank: String, totalxp: Int, totalskill: Int, combatlevel: Int, questscomplete: Int){
    print("setValues fired")
    greetingLabel.text = "Hello \(String(describing: username!))"
    rankLabel.text = "Rank: \(rank)"
    totalxpLabel.text = "Total Xp: \(totalxp)"
    totalskillLabel.text = "Total Level: \(totalskill)"
    combatlevelLabel.text = "Combat Level: \(combatlevel)"
    questscompleteLabel.text = "Quests Complete: \(questscomplete)"
}

func parseJson(username: String){
    let jsonUrlString = "https://apps.runescape.com/runemetrics/profile/profile?user=" + username
    guard let url = URL(string: jsonUrlString) else {
        print("guard let url failed")
        return }

    print(jsonUrlString)
    var user: User!
    var skills = [Skill]()
    print("This fired")

    URLSession.shared.dataTask(with: url) { (data, response, error) in
        print("This also fired")

        guard let data = data else {
            print("guard let data failed")
            return
        }

        print("This too fired")

        do {
            print("do fired")
            user = try JSONDecoder().decode(User.self, from: data)
            skills = try JSONDecoder().decode([Skill].self, from: data)
            for eachSkill in skills {
                //print("\(eachSkill.id)  \(eachSkill.level)")
            }
            if user.rank != nil {
                print("User values", user.rank!, user.totalxp!, user.totalskill!, user.combatlevel!, user.questscomplete!)
                DispatchQueue.main.async {
                    self.setValues(rank: user.rank!, totalxp: user.totalxp!, totalskill: user.totalskill!, combatlevel: user.combatlevel!, questscomplete: user.questscomplete!)
                }
            } else {
                let alert = UIAlertController(title: "Invalid Name", message: "The name you specified could not be found", preferredStyle: UIAlertControllerStyle.alert)
                alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.default, handler: nil))
                self.present(alert, animated: true, completion: nil)
            }
        }
        catch let jsonError {
            print("Error serializing json: ", jsonError)
        }

    }.resume()

}

}

Answer 1

仅当您从根对象开始解码所有(您需要的)一次时，隐式解码才有效。

此结构声明可对 User 和 Skill 进行解码。由于 API 似乎发送所有属性的值，因此无需使用选项。

struct User: Decodable {

    private enum CodingKeys: String, CodingKey {
        case rank, totalxp, totalskill, combatlevel, questscomplete
        case skills = "skillvalues"
    }

    var rank: String
    var totalxp: Int
    var totalskill: Int
    var combatlevel: Int
    var questscomplete: Int

    var skills : [Skill]
}

struct Skill: Decodable {
    var level: Int
    var xp: Int
    var rank: Int
    var id: Int
}

然后使用一个解码线:

user = try JSONDecoder().decode(User.self, from: data)
skills = user.skills

如果您只需要 skills 部分，请将 User 声明为

struct User: Decodable {

    private enum CodingKeys: String, CodingKey {
        case skills = "skillvalues"
    }

    var skills : [Skill]
}