tableview单元上的组件不可见

Question

I am building a table view contains just a button, with different labels.

I am using a table view to present a list of buttons.

this a structure containing names of the buttons.

struct post {
   let name : String
} 

I have pushed data from firebase to structure post.

var posts = [post]()
override func viewDidLoad() {
       super.viewDidLoad()
        let db = Firestore.firestore()
        db.collection(Auth.auth().currentUser?.uid as Any as! String).getDocuments() { (querySnapshot, err) in
            if let err = err {
                print("Error getting documents: \(err)")
            } else {
                for document in querySnapshot!.documents {
                   // print("\(document.documentID) => \(document.data())")
                    self.posts.insert(post(name: document.documentID), at: 0)
                }
                self.contents.reloadData()
            }
        }
    }

these are normal functions of table view

public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
       return posts.count
    }
    public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! cellview
        cell.programnames.titleLabel?.text = posts[indexPath.row].name
        return cell
    }

cellview.swift is designed as follow

class cellview: UITableViewCell {


    @IBOutlet weak var programnames: UIButton!
    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
    }

Please tell me my mistake in it. Button 'programnames' are not visible in table view in simulator

Answer 1

I see a couple of things missing that could be causing UITableViewDataSource not to be called

1. You need to set UITableView.dataSource = self in viewDidLoad

2. You need to register cellview.xib in viewDidLoad , like so:

    contents.register(UINib(nibName: "cellview", bundle: nil), forCellReuseIdentifier: "Cell") 

3. Optionals are for the reason that these can be nil and if it did your app will crash, avoid force unwrapping optionals ! , here is example guard statement with optional chaining

    guard err == nil, let documents = querySnapshot?.documents else { // error handling here return } self.posts = documents.map { post(name: $0.documentID) } 

4. I saw in your code using posts.insert(..., at: 0) which will reverse the array, if its on purpose use following instead:

    self.posts = documents.map({ post(name: $0.documentID) }).reversed()