我正在创建一个虚拟的社交媒体应用程序，但UITableView的行为并不是我所期望的。数据检索操作后，UITableView未显示提取的内容。下面是我的FeedViewController的代码：

import UIKit
import FirebaseFirestore
class FeedViewController: UIViewController, UITableViewDelegate, UITableViewDataSource  {
    
    @IBOutlet weak var tableView: UITableView!
    
    var postArray = [[String: Any]]()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.delegate = self
        tableView.dataSource = self
        getDataFromFirestore(){
            print("self.tableView.reloadData() called from viewDidLoad()")
            self.tableView.reloadData()
        }
    }
    
    override func viewDidAppear(_ animated: Bool) {
        print("self.tableView.reloadData() called from viewDidAppear()")
        self.tableView.reloadData()
    }
    
    func getDataFromFirestore(completion: @escaping() -> Void){
        let ref = Firestore.firestore().collection("posts")
        ref.addSnapshotListener { snapshot, error in
            if error != nil {
                self.makeAlert(title: "Error", message: error?.localizedDescription ?? "An error occoured during the process.")
            } else {
                if !(snapshot?.isEmpty ?? true) {
                    for doc in snapshot!.documents {
                        var dict = [String: Any]()
                        dict["userID"] = doc.get("userID") as? String
                        dict["comment"] = doc.get("comment") as? String
                        dict["imageURL"] = doc.get("imageURL") as? String
                        dict["likes"] = doc.get("likes") as? String
                        self.postArray.append(dict)
                    }
                }
                print("self.postArray.count been accessed from getDataFromFirestore():  \(self.postArray.count)")
            }
        }
        completion()
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! FeedCell
        cell.lblUserEmail.text = self.postArray[indexPath.row]["userID"] as! String? ?? ""
        cell.lblLikes.text = self.postArray[indexPath.row]["likes"] as! String? ?? ""
        cell.lblUserComment.text = self.postArray[indexPath.row]["comment"] as! String? ?? ""
        return cell
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        print("self.postArray.count been accessed from numberOfRowsInSection:  \(self.postArray.count)")
        return postArray.count
    }
    
    func makeAlert(title: String, message: String) {
            let controller = UIAlertController(title: title, message: message, preferredStyle: UIAlertController.Style.alert)
            let action = UIAlertAction(title: "OK", style: UIAlertAction.Style.default)
            controller.addAction(action)
            self.present(controller, animated: true)
        }
}

字符串

控制台输出：

self.tableView.reloadData() called from viewDidLoad()
self.postArray.count been accessed from numberOfRowsInSection:  0
self.postArray.count been accessed from numberOfRowsInSection:  0
self.postArray.count been accessed from numberOfRowsInSection:  0
self.tableView.reloadData() called from viewDidAppear()
self.postArray.count been accessed from numberOfRowsInSection:  0
self.postArray.count been accessed from getDataFromFirestore():  1

型
下面是我的UITableViewCell的代码：

import UIKit
class FeedCell: UITableViewCell {
    @IBOutlet weak var lblUserComment: UILabel!
    @IBOutlet weak var lblUserEmail: UILabel!
    @IBOutlet weak var imgView: UIImageView!
    @IBOutlet weak var lblLikes: UILabel!
    
    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }
    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
        // Configure the view for the selected state
    }
    @IBAction func btnLikeClicked(_ sender: Any) {
    }
}

型

Firestore数据：

屏幕输出（空白，无数据）：

的