从Firebase提取用户数据？

Question

目前，我正在以这种方式显示用户的联系人

 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()

    })

如何仅显示与addedByUser列中具有相同电子邮件的用户？ 当您创建新的联系人时，它将自动将您的电子邮件的值分配给addByUser。 因此，例如，如果我从帐户show@mycontact.com添加联系人，它将仅显示具有添加值的联系人。ByUser：“ show @ mycontact”

Answer 1

更新的答案-有两个选项:-)

    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)
    })

另一方面，考虑到仍然要遍历快照，您总是可以采用简单的方法

    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)
    })