Swift Firebase查询嵌套子节点

Question

我在firebase中进行了以下设置：

然后我查询firebase：

func getUserInfo(){

var tempUsers = [user]()
           // query for the data 
        let itemRef = Database.database().reference(fromURL: "[url]").child("users")
        itemRef.observe(.value, with: { snapshot in

            for child in snapshot.children {

        if let childSnapshot = child as? DataSnapshot,
            let dict = childSnapshot.value as? [String: Any], 
            let sport = dict["Sport"] as? String, 
            let username = dict["username"] as? String{

                let user = user(sport: sport, username: username)

                tempUsers.append(user)
            }
         }
             self.usersArray = tempUsers                           

        }){ (error) in
            print("the error is: \(error.localizedDescription)")
        }
  }

用户：

    class user {

            var username: String 
            var sport: String
            var teamInfo: [teamInfo]


      init(username: String, sport: String, teamInfo: [teamInfo])
  {
    self.username = username
    self.sport = sport
    self.teamInfo = [teamInfo]

  }
}

struct teamInfo {
  var AwayTeam: String
  var HomeTeam = String
  var Jersey = Int

}

我想知道如何在查询中获取Team信息，然后将其添加到User实例，我试图将“ Team”变成dict，但这不能给出我得到预期的结果。

Answer 1

第一件事：username中存在不一致之处。您的JSON用大写的Username来拼写U，而代码使用的是username和小写的u。由于Firebase区分大小写，因此您的代码现在永远不会获得正确的值。

除此之外，您还可以使用DataSnapshot.childSnapshot(forPath:)从嵌套子项中获取值。

itemRef.observe(.value, with: { snapshot in
    for child in snapshot.children {

    if let childSnapshot = child as? DataSnapshot,
        let dict = childSnapshot.value as? [String: Any], 
        let team = childSnapshot.childSnapshot(forPath: "Team/AwayTeam").value as? String;