Question

我正在开发Swift 4并且目前正在使用Walmart的API来展示他们的产品和有关产品的某些信息（例如：产品名称，产品价格）。我已经阅读并观看了许多关于解析JSON数据的教程，但是我继续得到同样的错误。如果有人能告诉我为什么我会收到错误，我将非常感谢看到我在这个问题上被困了好几天。

以下是我从API调用获得的JSON数据：

{
query: "ipod",
sort: "relevance",
format: "json",
responseGroup: "base",
totalResults: 3570,
start: 1,
numItems: 10,
items: [
{
    itemId: 15076191,
    parentItemId: 15076191,
    name: "Apple iPod Touch 4th Generation 32GB with Bonus Accessory Kit",
    salePrice: 189
 }

我只是想显示name和salePrice数据，但我目前无法这样做，而是收到此错误：typeMismatch(Swift.Array<Any>, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Array<Any> but found a dictionary instead.", underlyingError: nil))

这是我的数据模型：

  struct Product: Codable {
    let name: String
    let salePrice: String

}

以下是我的ViewController类中的代码：

class ViewController: UIViewController {


import Foundation
import UIKit    


var products: [Product]?
override func viewDidLoad() {
    super.viewDidLoad()



    let urlString = "http://api.walmartlabs.com/v1/search?query=sauce&format=json&apiKey=xyz"
    guard let url = URL(string: urlString) else { return }

    URLSession.shared.dataTask(with: url) { (data, response, error) in
        if error != nil {
            print(error!.localizedDescription)
        }

        guard let data = data else { return }
        //Implement JSON decoding and parsing
        do {
            //Decode retrived data with JSONDecoder and assing type of Article object
            let productData = try JSONDecoder().decode([Product].self, from: data)
            print(productData)

        } catch let jsonError {
            print(jsonError)
        }

    }.resume()



}


}

Answer 1

就像这样，

struct Item: Codable {
    let query: String
    let sort: String
    let responseGroup: String
    let totalResults: Int
    let start: Int
    let numItems: Int
    let items: [Product]
}

struct Product: Codable {
    let name: String
    let salePrice: CGFloat
}

尝试使用它，

let productData = try JSONDecoder().decode(Item.self, from: data)

Answer 2

你的json数据是一个字典而不是你解析它并得到数组的数组，或试试这个

struct Item: Codable {
   let query: String
   let sort: String
   let format: String
   let responseGroup: String
   let totalResults: Int
   let start: Int
   let numItems: Int
   let items: [Product]

}

struct Product: Codable {
   let itemId: Double 
   let parentItemId: Double 
   let name: String
   let salePrice: Int

}

let productData = try JSONDecoder().decode(Item.self, from: data)

如何从API显示JSON数据？

2 个答案: