ios - 如何使用 JSONEncoder 对嵌套数组进行编码

Question

我尝试使用 JSONEncoder 将四个不同的数组编码为 json 格式，但无法转换数组。所以，请帮帮我。我在 iOS 11 上使用 swift 4、xcode 9。

我的数组是:

var timeCart //dynamic data as string
var nameCart //dynamic data as string, ex. ["myNameOne", "myNameTwo", ...]
var quantityCart //dynamic data as Int, ex. [2, 3, 5, ...]
var priceCart //dynamic data as Int, ex. [82, 73, 65, ...]

我的结构是:

struct OrderDetailJSON: Encodable {
    let allOrder: [AllOrder]
    let TaxDetials: TaxDetail

    struct AllOrder: Encodable {
        let date_time: String
        let item: String
        let name: String
        let price: String
    }

    struct TaxDetail: Encodable {
        let tax_per: String
        let tax_name: String
    }
}

我试图在 TableView 内像这样编码

let orderDetailsJSON = OrderDetailJSON(allOrder: [.init(date_time: "\(quantityCart[indexPath.row])", item: "\(quantityCart[indexPath.row])", name: "\(nameCart[indexPath.row])", price: "\(priceCart[indexPath.row])")], TaxDetials: .init(tax_per: defaults.string(forKey: "STORE_TAX")!, tax_name: defaults.string(forKey: "STORE_TAX_NAME")!))
        do {
            let jsonData = try JSONEncoder().encode(orderDetailsJSON)
            let jsonString = String(data: jsonData, encoding: .utf8)
            print("order_details :" + jsonString!)
        }catch{

        }

我得到的输出是:

order_details: {
  "TaxDetials": {
    "tax_per": "5",
    "tax_name": "CGST & SGST"
  },
  "allOrder": [
    {
      "date_time": "2",
      "name": "Manchurian",
      "item": "2",
      "price": "87"
    }
  ]
}order_details: {
  "TaxDetials": {
    "tax_per": "5",
    "tax_name": "CGST & SGST"
  },
  "allOrder": [
    {
      "date_time": "3",
      "name": "Paneer Tikka",
      "item": "3",
      "price": "150"
    }
  ]
}order_details: {
  "TaxDetials": {
    "tax_per": "5",
    "tax_name": "CGST & SGST"
  },
  "allOrder": [
    {
      "date_time": "2",
      "name": "snacks",
      "item": "2",
      "price": "54"
    }
  ]
}

我期望的输出是:

order_details: {
  "TaxDetials": {
    "tax_per": "5",
    "tax_name": "CGST & SGST"
  },
  "allOrder": [
    {
      "date_time": "2",
      "name": "Manchurian",
      "item": "2",
      "price": "87"
    },
    {
      "date_time": "3",
      "name": "Paneer Tikka",
      "item": "3",
      "price": "150"
    },
    {
      "date_time": "2",
      "name": "snacks",
      "item": "2",
      "price": "54"
    }
  ]
}

Answer 1

您的结构声明没有任何问题(除了您应该遵守 Swift 命名约定，即变量名称采用小驼峰命名法 - taxPer 而不是 tax_per等，并且您的属性名称未使用正确的复数/单数形式)。

问题是您正在为每个 TableView 单元格定义一个 OrderDetailJSON 实例，而您的 TaxDetails 似乎对于表中的所有单元格都应该相同，并且您实际上想要创建一个 OrderDetailJSON 实例，其 allOrder 数组属性为每个 TableView 单元格包含一个 AllOrder 实例。您需要将 allOrder 属性更改为可变才能使其正常工作。

class YourTableViewController: UITableViewController {
    var orderDetails: OrderDetailJSON
    ...
    // You might need to use a different tableView function depending on your exact needs
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        orderDetails.allOrder[indexPath.row] = AllOrder(date_time: "\(quantityCart[indexPath.row])", item: "\(quantityCart[indexPath.row])", name: "\(nameCart[indexPath.row])", price: "\(priceCart[indexPath.row])")
    }
}

您需要确保使用正确的 TaxDetails 初始化 orderDetails，并且向 allOrder 预分配相同数量的元素您将拥有的表格 View 单元格。您只需在所有单元格都填满信息后将 orderDetails 转换为 JSON，无需逐个单元格执行此操作。