使用存储在Firebase数据库中的数据填充UITableView

pod 'Firebase/Core'
pod 'Firebase/Database'

import Firebase

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    FirebaseApp.configure()
    return true
}

class User {
    var name: String
    var email: String
    
    init(name: String, email: String) {
        self.name = name
        self.email = email
    }
    
    // 从字典初始化
    init?(snapshot: DataSnapshot) {
        guard let dict = snapshot.value as? [String: AnyObject],
              let name = dict["name"] as? String,
              let email = dict["email"] as? String else { return nil }
        
        self.name = name
        self.email = email
    }
}

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
    @IBOutlet weak var tableView: UITableView!
    
    var users: [User] = []
    var ref: DatabaseReference!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView.dataSource = self
        tableView.delegate = self
        
        ref = Database.database().reference(withPath: "users")
        ref.observe(.value, with: { snapshot in
            var newUsers: [User] = []
            
            for child in snapshot.children {
                if let snapshot = child as? DataSnapshot,
                   let user = User(snapshot: snapshot) {
                    newUsers.append(user)
                }
            }
            
            self.users = newUsers
            self.tableView.reloadData()
        })
    }
    
    // UITableViewDataSource methods
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return users.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "UserCell", for: indexPath)
        let user = users[indexPath.row]
        cell.textLabel?.text = user.name
        cell.detailTextLabel?.text = user.email
        return cell
    }
}

tableView.register(UITableViewCell.self, forCellReuseIdentifier: "UserCell")