Swift从Firebase数据库中获取特定值

I'm trying to get a specific value from Firebase Database. I looked some of the documents such as Google's, but I couldn't do it. Here is the JSON file of the database:

我试图从Firebase数据库获得一个特定的值。我看了一些文件，比如谷歌，但是我做不到。这是数据库的JSON文件:

{
    "Kullanıcı" : {
        "ahmetozrahat25" : {
            "E-Mail" : "ahmetozrahat25@gmail.com",
            "Yetki" : "user"
        },
        "banuozrht" : {
            "E-Mail" : "banuozrahat@gmail.com",
            "Yetki" : "user"
        }
    }
}

Swift Code:

斯威夫特代码:

ref?.child("Kullanıcı").child(userName.text!).observeSingleEvent(of: .value, with: { (snapshot) in

    if let item = snapshot.value as? String{
        self.changedName = item
    }
})

I want to get E-Mail value of a user, not everybody's. How can I do that?

我想获得用户的电子邮件价值，而不是每个人的。我怎么做呢?

3 个解决方案

#1

At last I found a solution. If I declare a var and try to use later it returns nil, but if I try use snapshot.value as? String it's ok. Here is a example I did.

最后我找到了一个解决办法。如果我声明一个var并尝试稍后使用它会返回nil，但是如果我尝试使用snapshot。值吗?字符串没关系。这是我做的一个例子。

    ref: FIRDatabaseReference?
    handle: FIRDatabaseHandle?

    let user = FIRAuth.auth()?.currentUser

    ref = FIRDatabase.database().reference()

    handle = ref?.child("Kullanıcı").child((user?.uid)!).child("Yetki").observe(.value, with: { (snapshot) in

        if let value = snapshot.value as? String{

            if snapshot.value as? String == "admin"{
                self.items.append("Soru Gönder")
                self.self.tblView.reloadData()
            }
        }
    })

#2

In your code, the snapshot will contain a dictionary of child values. To access them, cast the snapshot.value as a Dictionary and then accessing the individual children is a snap (shot, lol)

在代码中，快照将包含子值字典。要访问它们，请选择快照。值作为一个字典，然后访问各个子元素是一个简单的过程(shot, lol)

ref?.child("Kullanıcı").child(userName.text!)
                       .observeSingleEvent(of: .value, with: { (snapshot) in

    let userDict = snapshot.value as! [String: Any]

    let email = userDict["E-Mail"] as! String
    let yetki = userDict["Yetki"] as! String
    print("email: \(email)  yetki: \(yetki)")
})

#3

Add the "E-Mail" child to the query.

将“电子邮件”子元素添加到查询中。

ref?.child("Kullanıcı").child(userName.text!).child("E-Mail").observeSingleEvent(of: .value, with: { (snapshot) in

    if let item = snapshot.value as? String{
        self.changedName = item
    }
})

#1