UITableViewCell does not show cell until I navigate to parent view controller and come back

Question

My tableview does not show cell data until I tap on back button and return to table view controller. My app is loading data from Firebase.

class ViewPostsViewController : UIViewController, UITableViewDelegate, UITableViewDataSource {

@IBOutlet weak var tableView: UITableView!
var category : String = ""
var data = [Post]()

override func viewDidLoad() {
    super.viewDidLoad()
    
    title = category.capitalized
    
    tableView.delegate = self
    tableView.dataSource = self
    
}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    data = DataProvider.posts
    tableView.reloadData()
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 1
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! Cell
    
    let postsData = data[indexPath.section]
    
        cell.viewCell(post: postsData)
  
    return cell
}

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

The data provider class is

static func getPost(categoryString : String) -> [Post] {      
    var result = [Post]()
    let db = Firestore.firestore()
    db.collection("posts").getDocuments() {(querySnapshot, error) in
        for document in querySnapshot!.documents {
            if document.get("category") as! String == categoryString {
            let post = Post(title : document.get("title") as! String,
                            offering : document.get("offering") as! String,
                            category : document.get("category") as! String,
                            documentId : document.documentID)
            
            result.append(post)
        }
        }
        
    }
    return result
    
}

Answer 1

You did not load tableview when calling get post method. You have to reload tableview. and don't forget add dispatch queue main thread. I hope this code will help.

static func getPost(categoryString : String) -> [Post] {
var result = [Post]()
let db = Firestore.firestore()
db.collection("posts").getDocuments() {(querySnapshot, error) in
    for document in querySnapshot!.documents {
        if document.get("category") as! String == categoryString {
        let post = Post(title : document.get("title") as! String,
                        offering : document.get("offering") as! String,
                        category : document.get("category") as! String,
                        documentId : document.documentID)

        result.append(post)
      DispatchQueue.main.async {
       self.tableView.reloadData()
   }
    }
    }
    
  

}
return result

}