在提到的网址中，我只需要从网址中获取第一本字典吗？

Question

在这个订单详细信息数组中，我有 10 个字典，但我只需要显示第一个字典，谁能帮我实现这个？

http://www.json-generator.com/api/json/get/bUKEESvnvS?indent=2

下面是我的代码

func downloadJsonWithURL() {
        let url = NSURL(string: self.url)
        URLSession.shared.dataTask(with: (url as URL?)!, completionHandler: {(data, response, error) -> Void in
            if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary {
               self.orderdetailsArray = (jsonObj!.value(forKey: "Orders detail") as? [[String: AnyObject]])!
                for array in self.orderdetailsArray {
                    let key = "OrderId"
                    let value = "#1000501"
                    for (key,value) in array{
                    if let addressDict = array as? NSDictionary{
                        if let orderid = addressDict.value(forKey: "OrderId"){
                            self.orderid.append(orderid as! String)
                        }
                        if let orderdate = addressDict.value(forKey: "OrderDate"){
                            self.orderdate.append(orderdate as! String)
                        }
                        if let subtotal = addressDict.value(forKey: "SubTotal"){
                            self.subTotal.append(subtotal as! Int)
                        }
                        if let Shipping = addressDict.value(forKey: "Shipping"){
                            self.shippingPrice.append(Shipping as! Int)
                        }
                        if let tax = addressDict.value(forKey: "Tax"){
                            self.tax.append(tax as! Int)
                        }
                        if let grandtotal = addressDict.value(forKey: "GrandTotal"){
                            self.grandTotal.append(grandtotal as! Int)
                        }
                        if let shippingAddress = addressDict.value(forKey: "ShippingAddress"){
                            self.shippingAddress.append(shippingAddress as AnyObject)
                        }
                        if let shippingMethod = addressDict.value(forKey: "ShippingMethod"){
                            self.shippingMethod.append(shippingMethod as AnyObject)
                        }
                        if let billingAddress = addressDict.value(forKey: "BillingAddress"){
                            self.billingAddress.append(billingAddress as AnyObject)
                        }
                        if let paymentMethod = addressDict.value(forKey: "PayMentMethod"){
                            self.paymentMethod.append(paymentMethod as AnyObject)
                        }
                        self.itemsArray = addressDict.value(forKey: "Items detail") as! [[String : AnyObject]]
                    }
                }
                }
                OperationQueue.main.addOperation({
                    self.tableDetails.reloadData()
                })
            }
        }).resume()
    }

Answer 1

这样做。 ：

let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary

guard let Ordersdetail = jsonObj["Orders detail"] as? [NSDictionary] else {
        print("Cannot find key 'Orderdetails' in \(jsonObj)")
        return
    }

要访问第一个字典的内容，请执行以下操作：

 var orderid = Ordersdetail[0]["OrderId"]!
 var shippingadress = Ordersdetail[0]["ShippingAddress"]!
 var total = Ordersdetail[0]["GrandTotal"]!
 var subtotal = Ordersdetail[0]["SubTotal"]!
 var tax = Ordersdetail[0]["Tax"]!
 var shipping = Ordersdetail[0]["Shipping"]!

Answer 2

你好，如果你想要第一个字典

self.orderdetailsArray

然后

if let firstDictInfo = self.orderdetailsArray.first as? [String:Any] {
 // Do your stuff here
 print(firstDictInfo["OrderId"])
}

Answer 3

而不是遍历整个字典是字典，你应该只取第一个字典并只解析它。您的代码还有很多其他概念性问题。在 Swift 中，不要使用NSDictionary，而是使用原生 Swift 版本，Dictionary，它保留了其内容的类型信息。此外，使用条件转换确保即使接收到的数据错误/意外，您的程序也不会崩溃，并且不要使用强制解包选项。

此外，在 Swift 中解析 JSON 响应时，通常没有必要也不是一个好主意来遍历响应中字典的键值对。您应该知道您期望的数据结构，否则您将无法正确解析它，并且由于您可以在 Swift 中直接访问字典值，如果您知道它对应的键，则无需在循环中遍历字典。

func downloadJsonWithURL() {
        let url = URL(string: self.url)
        URLSession.shared.dataTask(with: url!, completionHandler: {(data, response, error) -> Void in
            if let jsonObj = (try? JSONSerialization.jsonObject(with: data!, options: .allowFragments)) as? [String:Any] {
               guard let self.orderdetailsArray =  jsonObj["Orders detail"] as? [[String: AnyObject]] else {return}
               guard let firstOrderDetails = self.orderdetailsArray.first else {return}
               let key = "OrderId"
               let value = "#1000501"
               if let ordered = firstOrderDetails["OrderId] as? String {
                   self.orderid.append(orderid)
               }
               if let orderdate = firstOrderDetails["OrderDate"] as? String{
                   self.orderdate.append(orderdate)
               }
               if let subtotal = firstOrderDetails["SubTotal"] as? Int{
                   self.subTotal.append(subtotal)
               }
               if let shipping = firstOrderDetails["Shipping"] as? Int{
                   self.shippingPrice.append(shipping)
               }
               if let tax = firstOrderDetails["Tax"] as? Int{
                  self.tax.append(tax)
               }
               if let grandtotal = firstOrderDetails["GrandTotal"] as? Int{
                  self.grandTotal.append(grandtotal)
               }
               if let shippingAddress = firstOrderDetails[ "ShippingAddress"] as? AnyObject{ //why don't you store it as a String?
                  self.shippingAddress.append(shippingAddress)
               }
               if let shippingMethod = firstOrderDetails[ "ShippingMethod"] as? AnyObject{
                  self.shippingMethod.append(shippingMethod)
               }
               if let billingAddress = firstOrderDetails[ "BillingAddress"] as? AnyObject {
                  self.billingAddress.append(billingAddress)
               }
               if let paymentMethod = firstOrderDetails ["PayMentMethod"] as? AnyObject{
                  self.paymentMethod.append(paymentMethod)
               }
               guard let itemDetails = firstOrderDetails["Items detail"] as? [[String : AnyObject]] else {return}
               self.itemsArray = itemDetails
                    }
                }
                }
                OperationQueue.main.addOperation({
                    self.tableDetails.reloadData()
                })
            }
        }).resume()
    }

我尚未编译和运行代码，因此请务必检查是否有任何拼写错误/不一致之处。此外，请确保将存储的对象的类型从 AnyObjects 更改为特定类型。