Swift Firebase 访问子快照数据

Question

我目前正在尝试从 Swift 中的子快照访问数据。这是我的代码（在 Swift 3/Firebase 更新之前有效）：

 if let achievements = snapshot1.childSnapshotForPath("Achievements").children.allObjects as? [FIRDataSnapshot] {


                    if achievements.count != 0 {

                        if let val = achievements[0].value!["somevalue"] as? Int {
                            self.dict["somevalue"] = val
                        }


                    }

所以我在这里尝试做的是创建一个子快照（成就）的变量，并从中访问子快照数据。成就[0] 将简单地返回第一个值。但是，这似乎不起作用。我应该如何处理？

我目前已经在快照中执行此操作（'observeType:.ChildAdded'）

我的 Firebase 数据库如下所示：

Achievements{

randomId1 {
somevalue : somevalue
}

randomId2 {
somevalue2 : somevalue2
}
}

更新代码：

 func loadData() {

        ref.child("Players").observe(FIRDataEventType.childAdded) { (snapshot:FIRDataSnapshot) in

            if let value = snapshot.value as? [String:AnyObject], let username = value["Username"] as? String {

            }

            if let value = snapshot.value as? [String:AnyObject], let ranking = value["Rank"] as? String {

            }

            if let childSnapshot = snapshot.childSnapshot(forPath: "Achievements").children.allObjects as? [FIRDataSnapshot] {

                if childSnapshot.count != 0 {

                    if let achievement1 = childSnapshot[0].value!["Rookie"] as? String {
                        print(achievement1)
                    }

                }
            }

        }

    }

JSON 树：

Players {

PlayerID {

Username

Rank

Achievements {

Rookie: yes

}


}

Answer 1

试试看：-

 if let childSnapshot = snapshot.childSnapshot(forPath: "Achievements") as? FIRDataSnapshot{

                if let achievementDictionary = childSnapshot.value as? [String:AnyObject] , achievementDictionary.count > 0{

                    if let achieveMedal = achievementDictionary["Rookie"] as? String {

                        print(achieveMedal)

             }        
       }
    }