Decoding error: “Expected to decode Dictionary<String, Any> but found an array instead.”

Question

我在 JSON 解码方面遇到问题。我为这个问题红色了其他答案，我也做了同样的事情，但我仍然得到错误。我做错了什么？

URLSession.shared.dataTask(with: r) { (data, response, error) in
    do {
        guard let data = data else { return }
        let banners = try JSONDecoder().decode([Banner].self, from: data)
        print(banners)
    } catch let error as NSError {
            print(error)
        }
    }
}.resume()

struct Banner: Decodable {
    var title: String
    var desc: String
    var image: String
}

JSON响应：

[
     {
    "id": "b4a95512-8de2-4621-8956-3289e991fb0b",
    "image": "https://picsum.photos/500/324/"
    },
  {
   "id": "4e1c703d-4841-469b-be2e-8f15d6cbd0c3",
   "title": "Lays",
   "image": "https://picsum.photos/500/324/"
  },
  {
   "id": "4315705e-e6fc-4dfa-a52e-c9de2031ed53",
   "desc": "ФРУТОНЯНЯ Для детского питания с яблоком, для малышей от 0 до 3 лет",
   "image": "https://picsum.photos/500/324/"
  },
  {
   "id": "0b8e40ae-5e13-4bdd-905d-a13ffdd94b65",
   "title": "Бульмени",
   "desc": "ГОРЯЧАЯ ШТУЧКА Со сливочным маслом",
   "image": "https://picsum.photos/500/324/"
  }
]

Answer 1

您的结构中缺少一个 "id" 键。 desc 和 title 并未为 json 响应中的所有元素提供，因此它们应该是可选的。

改为使用此结构：

struct Banner: Codable {
    let id: String
    let image: String
    let title, desc: String?
}

此外，以这种方式捕获错误：

catch {
    print(error)
}

Decoding error: “Expected to decode Dictionary<String, Any> but found an array instead.”

Decoding error: “Expected to decode Dictionary<String, Any> but found an array instead.”

json

swift4