ios - swift Firebase 删除观察者

Question

我注意到喜欢或不喜欢的打印被触发的次数与我打开 View Controller 的次数一样多，所以我在 viewDidDisappear 中添加了一个删除观察者(我尝试了所有列出的)但它继续多次触发，有人可以帮助我吗？

这是我的代码:

 private var databaseHandle: FIRDatabaseHandle!
 var ref = FIRDatabase.database().reference()
 var isLiked: Bool = false
  override func viewDidLoad() {
        super.viewDidLoad()

isLiked = false

databaseHandle = ref.child("favperuser").child(FIRAuth.auth()!.currentUser!.uid).observe( .value, with:{(snap) in

            if snap.hasChild(self.detailId){

                print("is liked")
                self.isLiked = true
                 self.likeButton.setTitle("Unlike", for: .normal)

                self.likeButton.setImage(UIImage(named: "star-")?.withRenderingMode(.alwaysOriginal), for: .normal)
                self.likeButton.setImage(UIImage(named: "star-")?.withRenderingMode(.alwaysOriginal), for: .highlighted)

            }else{

                print("not liked")
                self.isLiked = false
                self.likeButton.setTitle("Like!", for: .normal)

                self.likeButton.setImage(UIImage(named: "star+")?.withRenderingMode(.alwaysOriginal), for: .normal)
                self.likeButton.setImage(UIImage(named: "star+")?.withRenderingMode(.alwaysOriginal), for: .highlighted)

            }


          })
        self.isLiked = false

}


      @IBAction func likePressed(_ sender: UIButton) {


        if self.isLiked == false {

            ref.child("favperuser").child( FIRAuth.auth()!.currentUser!.uid).updateChildValues([detailId: true])


        } else {


            ref.child("favperuser").child( FIRAuth.auth()!.currentUser!.uid).child(detailShellId).removeValue { (error, ref) in
                if error != nil {
                    print("error \(error)")
                }
            }



        }

    }



    override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)

    ref.removeObserver(withHandle: databaseHandle)

    ref.child("favperuser").removeObserver(withHandle: databaseHandle)
    ref.child("favperuser").child(FIRAuth.auth()!.currentUser!.uid).removeObserver(withHandle: databaseHandle)
}

Answer 1

请引用此链接:-

https://firebase.google.com/docs/database/ios/read-and-write#detach_listeners

此外，在通过处理程序删除所有引用后，只需 removeAllObservers 以防任何观察者离开并且它可能会继续同步，并且应该在收到来自 firebase 的快照后主要将其删除，因为我也面临同样的问题解决了我的问题。