如何在我的 ios 应用程序中检索嵌套的 firebase 数据？

Question

我在 firebase 中有嵌套数据库。 我必须从 firebase 读取数据到我的应用程序，但此时数据有点复杂，所以我无法正确检索。 我必须使用“adres”、“isim”、“tarih”和“urunler”节点，我也可以使用 childSnapshot 和 for 循环获取 adres 数据，但我失去了顺序。你能帮我有什么方法可以检索这种数据有订单吗？ 这是我的数据库 json：

"orders" : {
"kullanicilar" : {
  "D5wmYp3YyegUOwtpVeqa0IoKnqA2" : {
    "-Lu3Fl2QnSFa5vhrKOzv" : {
      "Tshirt" : 4,
      "adres" : {
        "siparis alinma adresi" : "Bostancı - Yan Yol - Yan apt no:4 - Kadıköy - 7 - 23 - 29.103910631539957 - 40.96400403065958",
        "siparis edilme adresi" : "Bostancı - Yan Yol - Yan apt no:4 - Kadıköy - 7 - 23 - 29.103910631539957 - 40.96400403065958"
      },
      "isim" : {
        "username" : "Testçi"
      },
      "tarih" : {
        "teslim alinma tarihi" : {
          "alinma saati" : "10:00 - 11:00",
          "alinma tarihi" : "19/11/2019"
        },
        "teslim edilme tarihi" : {
          "alinma tarihi" : "21/11/2019",
          "teslim saati" : "18:00 - 19:00"
        }
      },
      "toplam tutar" : {
        "toplam paket tutari" : 55.6
      },
      "urun adetleri" : {
        "adetler" : [ 4 ]
      },
      "urunler" : {
        "Tshirt" : 4
      }
    },
    "-Lu3G-97OfWJB1u34gJ8" : {
      "Sweatshirt" : 3,
      "Tshirt" : 4,
      "adres" : {
        "siparis alinma adresi" : "Bostancı - Yan Yol - Yan apt no:4 - Kadıköy - 7 - 23 - 29.103910631539957 - 40.96400403065958",
        "siparis edilme adresi" : "Bostancı - Yan Yol - Yan apt no:4 - Kadıköy - 7 - 23 - 29.103910631539957 - 40.96400403065958"
      },
      "isim" : {
        "username" : "Testçi"
      },
      "tarih" : {
        "teslim alinma tarihi" : {
          "alinma saati" : "18:00 - 19:00",
          "alinma tarihi" : "22/11/2019"
        },
        "teslim edilme tarihi" : {
          "alinma tarihi" : "27/11/2019",
          "teslim saati" : ""
        }
      },
      "toplam tutar" : {
        "toplam paket tutari" : 99.1
      },
      "urun adetleri" : {
        "adetler" : [ 4, 3 ]
      },
      "urunler" : {
        "Sweatshirt" : 3,
        "Tshirt" : 4
      }
    }
  },

在这里，我尝试从 firebase 获取数据，并将这些数据带到 arrays。 这里是我尝试检索的代码：

func firebaseConnection() {
    ref = Database.database().reference()
    ref?.child("orders").child("kullanicilar").observe(.childAdded, with: { (datasnapshot) in

        let imageD = datasnapshot
        self.userId = imageD.key

        self.ref?.child("orders").child("kullanicilar").child(self.userId).observe(.childAdded, with: { (snapshot) in


            // ADRESLERI TUTAN KOD BURASIDIR.. ADRESLERI ALIR VE HEM ARRAY HEM DE SOZLUGE KAYIT EDER..
            let adresChild = snapshot.childSnapshot(forPath: "adres")
            for adr in adresChild.children {
                let adresSnap = adr as! DataSnapshot
                self.adresValuesArray.append(adresSnap.value! as! String)

            }

            let tarihChild = snapshot.childSnapshot(forPath: "tarih").childSnapshot(forPath: "teslim alinma tarihi")
            for trh in tarihChild.children {
                let tarihSnap = trh as! DataSnapshot
                self.tarihValuesArray.append(tarihSnap.value! as! String)
            }

            let tarihChildteslim = snapshot.childSnapshot(forPath: "tarih").childSnapshot(forPath: "teslim edilme tarihi")
            for trhts in tarihChildteslim.children {
                let tarihTeslimSnap = trhts as! DataSnapshot
                self.tarihTeslimValuesArray.append(tarihTeslimSnap.value! as! String)

            }


            let urunlerChild = snapshot.childSnapshot(forPath: "urunler")

            for urn in urunlerChild.children {
                let urunSnap = urn as! DataSnapshot
                //self.urunlerArray.updateValue(urunSnap.value! as! Int, forKey: urunSnap.key as! String)

                self.urunlerArray.append(urunSnap)
                print(self.urunlerArray)



            }


            })
        })

}

Answer 1

我不知道这些节点名称是什么意思——也许是土耳其语，所以我使用的是类似的英文版本。

这是像你一样的结构

orders
   all_users
      uid_0
         TShirt: 4
         addresses:
            address_0: ""
            address_1: ""
         delivery_dates
            delivery_0
              delivery_date: "19/11/2019"
              delivery_time: "10:00 - 11:00"
            delivery_1
              delivery_date: "21/11/2019"
              delivery_time: "18:00 - 19:00"
         name
            username: "some username"

我们正在使用 .childAdded 来读取 all_users 中的每个 uid 节点——这将一次遍历它们，从而访问快照中返回的子数据。

这是读取每个用户节点并打印出所有数据的代码。

func readUserDeliveryInfo() {
    let ordersRef = self.ref.child("orders")
    let allUsersRef = ordersRef.child("all_users")
    allUsersRef.observe(.childAdded, with: { snapshot in
        let userId = snapshot.key
        print("data for user: \(userId)")

        let tshirt = snapshot.childSnapshot(forPath: "TShirt").value as? Int ?? 0
        print("t-shirt: \(tshirt)")

        let allAddresses = snapshot.childSnapshot(forPath: "addresses")
        let addressArray = allAddresses.children.allObjects as! [DataSnapshot]
        for addressSnap in addressArray {
            let addressKey = addressSnap.key
            let address = addressSnap.value as! String
            print("address: \(addressKey)  \(address)")
        }

        let allDeliveries = snapshot.childSnapshot(forPath: "delivery_dates")
        for delivery in allDeliveries.children.allObjects as! [DataSnapshot] {
            let deliveryId = delivery.key
            let deliveryDate = delivery.childSnapshot(forPath: "delivery_date").value as? String ?? "No date"
            let deliveryTime = delivery.childSnapshot(forPath: "delivery_time").value as? String ?? "No Time"
            print(deliveryId, deliveryDate, deliveryTime)
        }

        let nameSnap = snapshot.childSnapshot(forPath: "name")
        let userName = nameSnap.childSnapshot(forPath: "username").value as? String ?? "No username"
        print("username: \(userName)")
    })
}

和 output

data for user: uid_0
t-shirt: 4
address: address_0  some address 0
address: address_1  some address 1
delivery_0 19/11/2019 10:00 - 11:00
delivery_1 21/11/2019 18:00 - 19:00
username: some username

需要注意的几点：

Firebase DataSnapshot 非常强大，因此请尽可能利用它们 - 它们将保持数据有序并轻松访问子数据。

let tshirt = snapshot.childSnapshot(forPath: "TShirt")

当我确实需要迭代快照中的数据时，我将其转换为一个数组（与字典不同，它保持顺序），并将子数据转换为 DataSnapshots 本身。

let addressArray = allAddresses.children.allObjects as! [DataSnapshot]