如何从数据库中提取用户并使用Firebase将其列在表格视图中？

我正在使用firebase来创build一个iOS应用程序。 我想检索我的数据库中的所有用户，并在表格视图中显示他们的名字和个人资料图片。 这是我的TableViewCell代码：

 import UIKit import FirebaseDatabase import FirebaseAuth import SDWebImage class HomeTableViewCell: UITableViewCell { @IBOutlet weak var nameLabel: UILabel! @IBOutlet weak var profileImageView: UIImageView! @IBOutlet weak var likeImageView: UIImageView! @IBOutlet weak var messageImageView: UIImageView! @IBOutlet weak var likeCountButton: UIButton! var homeVC: HomeViewController? var postReference: DatabaseReference! var post: UserFile?{ didSet { updateView() } } var user: UserFile? { didSet { updateUserInfo() } } override func awakeFromNib() { super.awakeFromNib() nameLabel.text = "" let berryTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleLikeTap)) likeImageView.addGestureRecognizer(berryTapGesture) likeImageView.isUserInteractionEnabled = true } override func setSelected(_ selected: Bool, animated: Bool) { super.setSelected(selected, animated: animated) } func updateView() { if let photoURL = post?.picURL { profileImageView.sd_setImage(with: URL(string: photoURL)) } API.Post.REF_POSTS.child(post!.id!).observeSingleEvent(of: .value, with: { postSnapshot in if let postDictionary = postSnapshot.value as? [String:Any] { let post = UserFile.transformPost(postDictionary: postDictionary, key: postSnapshot.key) self.updateLike(post: post) } }) API.Post.REF_POSTS.child(post!.id!).observe(.childChanged, with: { snapshot in if let value = snapshot.value as? Int { self.likeCountButton.setTitle("\(value) berries", for: .normal) } }) } func updateLike(post: UserFile) { let imageName = post.berries == nil || !post.isBerried! ? "berry" : "berrySelected" likeImageView.image = UIImage(named: imageName) // display a message for berries guard let count = post.berryCount else { return } if count != 0 { likeCountButton.setTitle("\(count) berries", for: .normal) } else if post.berryCount == 0 { likeCountButton.setTitle("Be the first to Like this", for: .normal) } } func incrementberries(forReference ref: DatabaseReference) { ref.runTransactionBlock({ (currentData: MutableData) -> TransactionResult in if var post = currentData.value as? [String : AnyObject], let uid = Auth.auth().currentUser?.uid { var berries: Dictionary<String, Bool> berries = post["berries"] as? [String : Bool] ?? [:] var likeCount = post["berryCount"] as? Int ?? 0 if let _ = berries[uid] { // Unlike the post and remove self from stars likeCount -= 1 berries.removeValue(forKey: uid) } else { // Like the post and add self to stars likeCount += 1 berries[uid] = true } post["berryCount"] = likeCount as AnyObject? post["berries"] = berries as AnyObject? currentData.value = post return TransactionResult.success(withValue: currentData) } return TransactionResult.success(withValue: currentData) }) { (error, committed, snapshot) in if let error = error { print(error.localizedDescription) } if let postDictionary = snapshot?.value as? [String:Any] { let post = UserFile.transformPost(postDictionary: postDictionary, key: snapshot!.key) self.updateLike(post: post) } } } func handleLikeTap() { postReference = API.Post.REF_POSTS.child(post!.id!) incrementberries(forReference: postReference) } override func prepareForReuse() { super.prepareForReuse() profileImageView.image = UIImage(named: "industribune-default-no-profile-pic") } func updateUserInfo() { nameLabel.text = user?.username if let photoURL = user?.profileImageURL { profileImageView.sd_setImage(with: URL(string: photoURL), placeholderImage: UIImage(named: "industribune-default-no-profile-pic")) } } } 

我在我的HomeViewController上显示这个单元格：

 import UIKit import FirebaseAuth import FirebaseDatabase import FirebaseStorage import Firebase class HomeViewController: UIViewController { @IBOutlet weak var tableView: UITableView! @IBOutlet weak var activityIndicatorView: UIActivityIndicatorView! var posts = [UserFile]() var users = [UserFile]() override func viewDidLoad() { super.viewDidLoad() // for performance set an estimated row height tableView.estimatedRowHeight = 1 // but also request to dynamically adjust to content using AutoLayout tableView.rowHeight = UITableViewAutomaticDimension //tableView.delegate = self tableView.dataSource = self loadPosts() } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } func loadPosts() { activityIndicatorView.startAnimating() API.User.observePosts { (newPost) in guard let userID = newPost.uid else { return } self.fetchUser(uid: userID, completed: { // append the new Post and Reload after the user // has been cached self.posts.append(newPost) self.activityIndicatorView.stopAnimating() self.tableView.reloadData() }) } } func fetchUser(uid: String, completed: @escaping () -> Void) { API.User.observeUser(withID: uid) { user in self.users.append(user) completed() } } } extension HomeViewController: 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: "HomeTableViewCell", for: indexPath) as! HomeTableViewCell cell.post = posts[indexPath.row] cell.user = users[indexPath.row] cell.homeVC = self return cell } } 

我的项目中有很多疯狂的事情，所以让我知道如果你有任何问题 ，我做错了什么。 如果太复杂了，我已经准备好消除一切，重新开始。

我真的认为，我遵循所有的指导方针提出一个问题，所以不喜欢closures这个问题或东西。

Answer 1

这是很多代码。 试试这个超级简化的例子。 为此，用户节点仅将名称存储为子节点，但也可以具有图像，电子邮件，地址等。

示例用户节点

 users uid_0: name: "Bert" uid_1: name: "Ernie" 

和一些代码

 var usersArray = [ [String: Any] ]() //an array of dictionaries. class ViewController: UIViewController { //set up firebase references here override func viewDidLoad() { super.viewDidLoad() let usersRef = self.ref.child("users") usersRef.observeSingleEvent(of: .value, with: { snapshot in for child in snapshot.children { let snap = child as! DataSnapshot let userDict = snap.value as! [String: Any] self.usersArray.append(userDict) } self.tableView.reloadData() }) 

和tableView委托方法

 func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return self.usersArray.count } func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCell(withIdentifier: "HomeTableViewCell", for: indexPath) as! HomeTableViewCell let userDict = self.usersArray[indexPath.row] cell.text = userDict["name"] as! String //cell.imge = userDict["image"] etc etc return cell } 

现在…所有人都说了。 这是UserClass对象数组的完美用法，而不是字典。

这是一个起点….

 class UserClass { var name = "" var image = "" func init(snap: DataSnapshot) { //populate the vars from the snapshot } } var userClassArray = [UserClass]() 

不要复制和粘贴，因为有可能是错别字，但它应该指向你在正确的方向。