ios - 从 Firebase 数据库中检索整数，结果一无所有

Question

所以我正在从 Firebase 数据库中检索数据（整数）并将其打印为标签。但是，在检索数据并将其设置为标签的文本后，它只是空白（只是空的）。为什么会这样？

games-played 是一个整数

数据库 Json 文件：

{
  "mix-questions" : [ {
    "1" : "Eu Ro Wang",
    "2" : "Keerti Soundappan",
    "3" : "Galadriel Coury",
    "4" : "Madelyn Koch",
    "answer" : "Madelyn Koch",
    "question" : "Which one is not a national officer?"
  }, {
    "question" : "test"
  } ],
  "users" : {
    "0vFQYnfIbahHdC1RsuNMW45HYNR2" : {
      "email" : "[e-mail]",
      "username" : "itsandyjiang"
    },
    "Cs7sW01kSEYHYZmBISvjYc1QmDy1" : {
      "email" : "[e-mail]",
      "games-played" : 0,
      "username" : "test"
    },
    "GypKikOJbfOPV4m43mQTnLMWBYG3" : {
      "email" : "[e-mail]",
      "games-played" : 0,
      "username" : "andyjiang"
    },
    "Khf6jRX7uuZs40x8w7zapziCsr73" : {
      "email" : "[e-mail]",
      "games-played" : 0,
      "username" : "itsandyjiang3"
    },
    "OAa5bbNc65acxmr6mauyIQ6bqHb2" : {
      "email" : "[e-mail]",
      "games-played" : 0,
      "username" : "itsandyjiang2"
    },
    "YxxBBxS2WkWtrY8PnLx4jfDqV3o2" : {
      "email" : "[e-mail]",
      "games-played" : 0,
      "username" : "itsandyjiang5"
    },
    "taikB5Gp1kaAmuPpiHxPoiKmjf03" : {
      "email" : "[e-mail]",
      "games-played" : 0,
      "username" : "itsandyjiang9"
    }
  }
}

检索数据（“玩过的游戏”）并将其设置为标签的文本：

 func render() {
    let ref = Database.database().reference(fromURL: "https://testtest.firebaseio.com/")
    let userID = Auth.auth().currentUser?.uid
    ref.child("users").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in
        // Get user value
        let value = snapshot.value as? NSDictionary
        let username = value?["username"] as? String ?? ""
        let gamesPlayed = value?["games-played"] as? String ?? ""
        self.usernameLabel.text = username.  
        self.gamesPlayedLabel.text = gamesPlayed  //Setting of label from data

        // ...
    }) { (error) in
        print(error.localizedDescription)
    }
}

设置数据的位置：

let ref = Database.database().reference(fromURL: "https://testtest.firebaseio.com/")
                let usersReference = ref.child("users").child(user.uid)
                let values = ["username": self.usernameTextField.text!, "email": self.emailTextField.text!, "games-played": 0] as [String : Any]
                usersReference.updateChildValues(values, withCompletionBlock: { (err, ref) in
                    if err != nil {
                        print(err!)
                        return
                    }

                    //Successfully registered user's data to database

                    self.errorLabel.alpha = 0
                    self.present((self.storyboard?.instantiateViewController(withIdentifier: "TabBarViewController"))!, animated: false, completion: nil)


                })

标签： iosswiftfirebase

Answer 1

let gamesPlayed = value?["games-played"] as? String ?? "" 可能转换为字符串失败，你应该做的是as? Int然后转换为字符串