Firebase retrieve data below auto ID In Swift

问题

I'm in trouble in retrieving data from Firebase.

I'd like to read all contactName data in JSON under auto ID , then append to UIPickerView.

Here is my JSON tree (used childByAutoId())

And Here is my Swift Code

dbRef = Database.database().reference()

dbRef.child("user").child("contacts").queryOrdered(byChild: "contactName").observeSingleEvent(of: .value, with: {(snapshot) in

    for snap in snapshot.children {

        let userSnap = snap as! DataSnapshot

        let contactName = userSnap.value as? String

            self.pickOption.append("\(contactName)")
        }
    })

But the result shows me all nil data... looks like this.

How Can I fix it..?

回答1:

I solved myself!

But first of all, I decided not to use UIPickerView.

And what I wanna do is to add data below auto ID.

I'm not sure this is good algorithm for solving this problem, But Anyway, I made it :)

dbRef.child("user/contacts/").observe(.value, with: {(snapshot) in

    if let result = snapshot.children.allObjects as? [DataSnapshot] {

            for child in result {

                let orderID = child.key as String //get autoID

                self.dbRef.child("user/contacts/\(orderID)/contactName").observe(.value, with: { (snapshot) in

                    if let nameDB = snapshot.value as? String {

                        if self.debtorName == nameDB {

                            self.dbRef.child("user/contacts/\(orderID)").updateChildValues(data)
                        }
                    }
                })
            }
        }
    })

来源：https://stackoverflow.com/questions/44689303/firebase-retrieve-data-below-auto-id-in-swift