Unable to show user's username and profile image in post

Question

I'm building an instagram clone and I managed to let users post a photo from their library and add a caption. The photo is then successfully displayed in a feed table view with the caption. However, I am unable to show the username of the user who posted the photo and his profile picture. There are no errors at all, I carefully followed a tutorial on Udemy writing the exact same code but it just won't show up.

//feedViewController

import UIKit
import Firebase
import SDWebImage

class FeedViewController: UIViewController {

    @IBOutlet weak var tableView: UITableView!

    var posts = [Post]()

    override func viewDidLoad() {
        super.viewDidLoad()


        loadPosts()

        tableView.dataSource = self
        tableView.estimatedRowHeight = 375
        tableView.rowHeight = UITableView.automaticDimension
    }

    func loadPosts() {

        Database.database().reference().child("posts").observe(.childAdded) { (snapshot: DataSnapshot) in

            if let dict = snapshot.value as? [String: Any] {

                let newPost = Post.transformPost(dict: dict)
                self.posts.append(newPost)
                self.tableView.reloadData()

            }
        }
    }
}

extension FeedViewController: UITableViewDataSource {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return posts.count
    }


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

        let cell = tableView.dequeueReusableCell(withIdentifier: "PostCell", for: indexPath) as! HomeTableViewCell
        let post = posts[indexPath.row]

        cell.post = post

        return cell
    }
}

// HomeTableViewCell

import UIKit
import FirebaseDatabase
import SDWebImage

class HomeTableViewCell: UITableViewCell {

    @IBOutlet weak var profileImageView: UIImageView!
    @IBOutlet weak var usernameLabel: UILabel!

    @IBOutlet weak var postImageView: UIImageView!
    @IBOutlet weak var captionLabel: UILabel!

    @IBOutlet weak var cheerButton: UIButton!
    @IBOutlet weak var donateButton: UIButton!
    @IBOutlet weak var commentButton: UIButton!

    var post: Post? {
        didSet {
            updateView()
        }
    }

    func updateView() {

        captionLabel.text = post?.caption

        if let photoUrlString = post?.photoUrl {

            let photoUrl = URL(string: photoUrlString)
            postImageView.sd_setImage(with: photoUrl)
        }

        setUpUserInfo()
    }

    func setUpUserInfo() {

        if let uid = post?.uid {

            Database.database().reference().child("users").child(uid).observeSingleEvent(of: DataEventType.value, with: {
                snapshot in

                if let dict = snapshot.value as? [String: Any] {

                    let user = User.transformUser(dict: dict)
                    self.usernameLabel.text = user.username

                    if let photoUrlString = user.profileImageUrl {

                        let photoUrl = URL(string: photoUrlString)
                        self.profileImageView.sd_setImage(with: photoUrl)
                    }
                }
            })
        }
    }

    override func awakeFromNib() {
        super.awakeFromNib()

        usernameLabel.text = ""
        captionLabel.text = ""
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

    }
}

// Post (class)

import Foundation

class Post {

    var caption: String?
    var photoUrl: String?
    var uid: String?
}

extension Post {

    static func transformPost(dict: [String: Any]) -> Post {

        let post = Post()
        post.caption = dict["caption"] as? String
        post.photoUrl = dict["photoUrl"] as? String
        post.uid = dict["uid"] as? String

        return post

    }
}

// User (class)

import Foundation

class User {


    var email: String?
    var profileImageUrl: String?
    var username: String?
}

extension User {

    static func transformUser(dict: [String: Any]) -> User {

        let user = User()
        user.email = dict["email"] as? String
        user.profileImageUrl = dict["profileImageUrl"] as? String
        user.username = dict["username"] as? String

        return user
    }
}

Answer 1

感谢您的答复！无论如何，我只是发现问题出在哪里。我将数据库子引用设置为“用户”，而数据库中引用的真实名称为“用户”。愚蠢的错字错误...

再次感谢大家