Swift 3将Firebase数据写入TableView

Question

I am fetching all user id's from my Firebase database. When I execute the program I can see snapshot of all user id's on console via code in line 26. But the code is not writing to table cells. I done this with tutorial. Everything is same with video. But it does not work for me Where is the problem ?

    class ChatInfo: UITableViewController {

    let cellId = "cellId"
    var users = [User] ()

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Geri", style: .plain, target:self, action: #selector(handleCancel))
        fetchUser()
    }
    func handleCancel() {

        dismiss(animated: true, completion: nil)

    }
    func fetchUser() {

        Database.database().reference().child("locations").observe(.childAdded, with: {(snapshot) in

            if let dictionary = snapshot.value as? [String: AnyObject] {

                let user = User()

                user.userId = dictionary["userId"] as! String
                print(user.userId) // IT PRINTS ALL USERS  TO CONSOLE
                self.users.append(user)

                DispatchQueue.main.async(execute: {
                 self.tableView.reloadData()
                })
            }

        } , withCancel: nil)
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    override func numberOfSections(in tableView: UITableView) -> Int {
        return users.count
    }


    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = UITableViewCell(style: .subtitle, reuseIdentifier: cellId)

        let user = users[indexPath.row]
        cell.detailTextLabel?.text = user.userId
        return cell
    }
}

Answer 1

You are overriding the wrong method

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return users.count
}

And design the cell style in Interface Builder and use this method in cellForRowAt

let cell = tableView.dequeueReusableCell(withCellIdentifier: cellId, for: indexPath)

Answer 2

As per your requirement actual way for fetching records of tableview cell is this:

override func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return users.count
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withCellIdentifier: cellId, for: indexPath)
    let user = users[indexPath.row]
    cell.detailTextLabel?.text = user.userId
    return cell
}