使用 Swift 更新 Firebase 中的子值

Posted 2023-03-10

【中文标题】使用 Swift 更新 Firebase 中的子值

【英文标题】：Update child values in Firebase with Swift

【发布时间】：2017-03-22 00:27:52

【问题描述】：

我正在尝试在用户点击按钮后更新 Firebase 数据库。当用户登录时（在我的例子中是 Facebook），一个数据结构被成功创建，数据树中的初始值被创建。

我想要完成的是，一旦用户在应用程序中并且他们创建了一个新项目，它将其保存到数据库中，因此更新了已创建的子值之一下的值。请参阅我的代码和屏幕截图以供参考 - 感谢您的帮助！

// user taps button to send item to be updated in Firebase data tree
func confirmAddPlace() 

    // add place to tableview array
    let accessToken = FBSDKAccessToken.current()
    guard let accessTokenString = accessToken?.tokenString else  return 

    let credentials = FIRFacebookAuthProvider.credential(withAccessToken: accessTokenString)
    FIRAuth.auth()?.signIn(with: credentials, completion:  (user, error) in
        if error != nil 
            print("Something went wrong with our FB user: ", error ?? "")
            return
        

    guard let uid = user?.uid else 
        return
    
    // here is where i am having issues
    let ref = FIRDatabase.database().reference().root.child("Users").child(uid).child("Places")
    let values = ["place": self.placeNameLabel.text]
    ref.updateChildValues(values)
)

    animateOut()

func viewController(_ viewController: GMSAutocompleteViewController, didAutocompleteWith place: GMSPlace) 
        let placeID = place.placeID
        placesClient.lookUpPlaceID(placeID, callback:  (place, error) -> Void in
            if let error = error 
                print("lookup place id query error: \(error.localizedDescription)")
                return
            
            guard let place = place else 
                return
            
        )
        let selectedPlace = place.formattedAddress
        if let name = selectedPlace as String!
        
            self.placeNameLabel.text = "Are you sure you would like to add \(name) to your places?"
        
    

【问题讨论】：

您好，您解决了这个问题吗？如果可以，请问如何？

【参考方案1】：

您想更改Places 的值，即child(uid) 的子级中的值。

let values = ["place": self.placeNameLabel.text]
let ref = FIRDatabase.database().reference().root.child("users").child(uid).updateChildValues(["Places": values])

【讨论】：

谢谢！这确实有助于我尝试做的一件事。虽然有一些补充......我每次用户向数组添加新位置时都尝试创建一个项目......所以不仅仅是更新相同的子值，以及只将字符串的一部分保存到数据库.在用户从 GMSAutocompleteViewController 中选择之后，我已经在帖子中添加了额外的代码。所以我只想将名称值保存到 Firebase。再次感谢！

如何在upateChildValues的回调中获取更新节点的值？

【参考方案2】：

user3708224 - 你可以试试这个：

let values = ["place": self.placeNameLabel.text]
// create a child reference that uses a date as the key
let date = Date()
let ref = FIRDatabase.database().reference().root.child("users").child(uid).child(date).updateChildValues(["Places": values])

如果您想更好地控制日期对象中的组件，请尝试以下操作：

let calendar = Calendar.current
let year = calendar.component(.year, from: date)

// you can do the same with [.month, .day, .hour, .minute, and more]
// This will allow you to have control of how frequently they can update the DB
// And it will allow you to sort by date

如果您想将其作为字符串上传到 Firebase，请尝试以下操作：

/**
 This function returns the Date as a String
 - "Year-Month-Day"
 If the character ' / ' is used in place of ' - ' Firebase will make each component child of the previous component. 
 */
func getDate() -> String 
        let date = Date()
        let calendar = Calendar.current
        // hours + min:  -\(calendar.component(.hour, from: date))-\(calendar.component(.minute, from: date))
        return "\(calendar.component(.year, from: date))-\(calendar.component(.month, from: date))-\(calendar.component(.day, from: date))"

    

let values = ["place": self.placeNameLabel.text]
let ref = FIRDatabase.database().reference().root.child("users").child(uid).child(getDate()).updateChildValues(["Places": values])