从Firebase提取用户数据？

Question

Currently I'm displaying user's contacts this way

 ref.observe(.value, with: { snapshot in



        var newItems: [Contacts] = []

        for item in snapshot.children {
            let contact = Contacts(snapshot: item as! FIRDataSnapshot)
            newItems.append(contact)
        }

        // filter the data here
        let userID = FIRAuth.auth()?.currentUser?.email

        let itemsMatching  = self.items.filter {
            $0.addedByUser == userID
        }




        self.items = newItems
        let sortedNames = itemsMatching.sorted { $0.lastName < $1.lastName }
        self.tableView.reloadData()

    })

How can I display only users with same email as in column addedByUser? When u create a new contact it will automatically assign value of your email to addedByUser. So for example if I add contact from account show@mycontact.com it will display only contacts with value addedByUser: "show@mycontact"

Answer 1

Updated answer - with two options :-)

    let ref = FIRDatabase.database().reference(withPath: "contacts")

    var newItems : [ContactItem] = []

    ref.observe(.value, with: { snapshot in

        for item in snapshot.children
        {
            let item = ContactItem(snapshot: item as! FIRDataSnapshot)
            newItems.append(item)
        }

        let userID = FIRAuth.auth()?currentUser?.email

        let itemsMatching  = newItems.filter
        {
            $0.addedByUser == userID
        }

        let sortedNames = itemsMatching.sorted { $0.lastName < $1.lastName }

        print(sortedNames)
    })

On the other hand, given that you're iterating through the snapshot anyway, you could always go for the simple approach

    let ref = FIRDatabase.database().reference(withPath: "contacts")

    var newItems : [ContactItem] = []
    let userID = FIRAuth.auth()?currentUser?.email

    ref.observe(.value, with: { snapshot in

        for item in snapshot.children
        {
            let item = ContactItem(snapshot: item as! FIRDataSnapshot)
            if item.addedByUser == userID
            {
                newItems.append(item)
            }
        }

        let sortedNames = newItems.sorted { $0.lastName < $1.lastName }

        print(sortedNames)
    })