Bittrex API - Swift中的JSON结构

Question

我想在我的示例iOS应用程序中调用Bittrex api。

我想从这里读取JSON。 https://bittrex.com/api/v1.1/public/getmarketsummaries

但我收到此错误：预计解码阵列，但发现一本字典，而不是“，underlyingError：无）

根据谷歌搜索结果，JSON结构是不正确

。

如果我能犯了一个错误

这里是我的JSON结构;

struct MarketSummaries : Decodable{ 
    let success : Bool? 
    let message : String? 
    let result : [SummaryResult]? 
} 

struct SummaryResult : Decodable{ 
    let marketName : String? 
    let high : Double? 
    let low : Double? 
    let volume : Double? 
    let last : Double? 
    let baseVolume : Double? 
    let timeStamp : String? 
    let bid : Double? 
    let ask : Double? 
    let openBuyOrders : Int? 
    let openSellOrders : Int? 
    let prevDay : Double? 
    let created : String? 

    private enum CodingKeys : String, CodingKey { 
     case marketName = "MarketName", high = "High", low = "Low", volume = "Volume", 
     last = "Last", baseVolume = "BaseVolume", timeStamp = "TimeStamp", bid = "Bid", 
     ask = "Ask", openBuyOrders = "OpenBuyOrders", openSellOrders = "OpenSellOrders", 
     prevDay = "PrevDay", created = "Created" 
    } 
} 

这里是我的JSON结构;

let url = URL(string: "https://bittrex.com/api/v1.1/public/getmarketsummaries") 
let session = URLSession.shared 
let task = session.dataTask(with: url!) { (data, response, error) in 
    if error != nil {} 
    else 
    { 
     if (data != nil) 
     { 
      do 
      { 
       let coins = try JSONDecoder().decode([MarketSummaries].self, from: data!) 

       DispatchQueue.main.async { 
        self.market = coins 
        self.table.reloadData() 
       } 
      } 
      catch 
      { 
       print(error) 
      } 
     } 
    } 
} 
task.resume() 

Answer 1

我发现了自己的错误。我从JSON读取数据时阅读MarketSummaries。但它不是一个数组。

坏线：

let coins = try JSONDecoder().decode([MarketSummaries].self, from: data!) 

修正线

let coins = try JSONDecoder().decode(MarketSummaries.self, from: data!) 

Answer 2

你可以使用这个Result类来检索你的Json数据......我想这会帮助你。

import foundation 

public class Result { 
public var marketName : String? 
public var high : Double? 
public var low : Double? 
public var volume : Double? 
public var last : Double? 
public var baseVolume : Double? 
public var timeStamp : String? 
public var bid : Double? 
public var ask : Double? 
public var openBuyOrders : Int? 
public var openSellOrders : Int? 
public var prevDay : Double? 
public var created : String? 

/** Returns an array of models based on given dictionary. 

Sample usage: 
let result_list = Result.modelsFromDictionaryArray(someDictionaryArrayFromJSON) 

- parameter array: NSArray from JSON dictionary. 

- returns: Array of Result Instances. 
*/ 
public class func modelsFromDictionaryArray(array:NSArray) -> [Result] 
{ 
    var models:[Result] = [] 
    for item in array 
    { 
     models.append(Result(dictionary: item as! NSDictionary)!) 
    } 
    return models 
} 

/** 
Constructs the object based on the given dictionary. 

Sample usage: 
let result = Result(someDictionaryFromJSON) 

- parameter dictionary: NSDictionary from JSON. 

- returns: Result Instance. 
*/ 
    required public init?(dictionary: NSDictionary) { 

    marketName = dictionary["MarketName"] as? String 
    high = dictionary["High"] as? Double 
    low = dictionary["Low"] as? Double 
    volume = dictionary["Volume"] as? Double 
    last = dictionary["Last"] as? Double 
    baseVolume = dictionary["BaseVolume"] as? Double 
    timeStamp = dictionary["TimeStamp"] as? String 
    bid = dictionary["Bid"] as? Double 
    ask = dictionary["Ask"] as? Double 
    openBuyOrders = dictionary["OpenBuyOrders"] as? Int 
    openSellOrders = dictionary["OpenSellOrders"] as? Int 
    prevDay = dictionary["PrevDay"] as? Double 
    created = dictionary["Created"] as? String 
} 


/** 
Returns the dictionary representation for the current instance. 

- returns: NSDictionary. 
*/ 
    public func dictionaryRepresentation() -> NSDictionary { 

    let dictionary = NSMutableDictionary() 

    dictionary.setValue(self.marketName, forKey: "MarketName") 
    dictionary.setValue(self.high, forKey: "High") 
    dictionary.setValue(self.low, forKey: "Low") 
    dictionary.setValue(self.volume, forKey: "Volume") 
    dictionary.setValue(self.last, forKey: "Last") 
    dictionary.setValue(self.baseVolume, forKey: "BaseVolume") 
    dictionary.setValue(self.timeStamp, forKey: "TimeStamp") 
    dictionary.setValue(self.bid, forKey: "Bid") 
    dictionary.setValue(self.ask, forKey: "Ask") 
    dictionary.setValue(self.openBuyOrders, forKey: "OpenBuyOrders") 
    dictionary.setValue(self.openSellOrders, forKey: "OpenSellOrders") 
    dictionary.setValue(self.prevDay, forKey: "PrevDay") 
    dictionary.setValue(self.created, forKey: "Created") 

    return dictionary 
} 

}