我面临着将数据从 HomeViewController 传递到 PostDetailViewController 的问题， 我检查了连接到 View Controller 的类是否正确，连接到 XIB 文件的类是 PostTableViewCell，
并且仍然得到这个错误
'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key description
点击表格单元格
HOMEVIEWCONTROLLER
class HomeViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var tableView:UITableView!
var posts = [Post]()
var db: Firestore!
var postKey:String = ""
private var documents: [DocumentSnapshot] = []
//public var posts: [Post] = []
private var listener : ListenerRegistration!
override func viewDidLoad() {
super.viewDidLoad()
db = Firestore.firestore()
self.navigationController?.navigationBar.isTranslucent = false
tableView = UITableView(frame: view.bounds, style: .plain)
let cellNib = UINib(nibName: "PostTableViewCell", bundle: nil)
tableView.register(cellNib, forCellReuseIdentifier: "postCell")
tableView.backgroundColor = UIColor(white: 0.90,alpha:1.0)
view.addSubview(tableView)
var layoutGuide:UILayoutGuide!
if #available(iOS 11.0, *) {
layoutGuide = view.safeAreaLayoutGuide
} else {
// Fallback on earlier versions
layoutGuide = view.layoutMarginsGuide
}
tableView.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor).isActive = true
tableView.topAnchor.constraint(equalTo: layoutGuide.topAnchor).isActive = true
tableView.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor).isActive = true
tableView.bottomAnchor.constraint(equalTo: layoutGuide.bottomAnchor).isActive = true
tableView.delegate = self
tableView.dataSource = self
tableView.reloadData()
retrieveAllPosts()
//checkForUpdates()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func handleLogout(_ sender:Any) {
try! Auth.auth().signOut()
self.dismiss(animated: false, completion: nil)
}
func retrieveAllPosts(){
let postsRef = Firestore.firestore().collection("posts").limit(to: 50)
postsRef.getDocuments { (snapshot, error) in
if let error = error {
print(error.localizedDescription)
} else {
if let snapshot = snapshot {
for document in snapshot.documents {
let data = document.data()
// self.postKey = document.documentID
let username = data["username"] as? String ?? ""
let postTitle = data["postTitle"] as? String ?? ""
let postcategory = data["postcategory"] as? String ?? ""
let postContent = data["postContent"] as? String ?? ""
let newSourse = Post( _documentId: document.documentID, _username: username, _postTitle: postTitle, _postcategory: postcategory, _postContent: postContent)
self.posts.append(newSourse)
print(self.postKey)
}
self.tableView.reloadData()
}
}
}
}
/* postsRef.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 = querySnapshot!.documents.flatMap({Post(dictionary: $0.data())})
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
}
}*/
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
tableView.reloadData()
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
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! PostTableViewCell
cell.set(post: posts[indexPath.row])
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let post = self.posts[indexPath.row]
//print("row selected: \(indexPath.row)")
//Swift.print(post._documentId!)
let postKey = post._documentId
let postName = post._username
print(postKey! + postName!)
performSegue(withIdentifier: "toDetailView", sender: indexPath)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
//segue.forward(posts, to: segue.destination)
guard let details = segue.destination as? PostDetailViewController,
let index = tableView.indexPathForSelectedRow?.row
else {
return
}
details.detailView = posts[index]
}
}
POSTTABLEVIEWCELL
class PostTableViewCell: UITableViewCell {
@IBOutlet weak var usernameLabel: UILabel!
@IBOutlet weak var profileImageView: UIImageView!
@IBOutlet weak var subtitleLabel: UILabel!
@IBOutlet weak var postTextLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
// profileImageView.layer.cornerRadius = profileImageView.bounds.height / 2
// profileImageView.clipsToBounds = true
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
func set(post:Post) {
usernameLabel.text = post._username
postTextLabel.text = post._postTitle
subtitleLabel.text = post._postcategory
}
}
发布细节 View Controller
类 PostDetailViewController: UIViewController {
@IBOutlet var usernamelabel: UILabel!
@IBOutlet var posttitlelabel: UILabel!
@IBOutlet var postIdlabel: UILabel!
// @IBOutlet var description: UILabel!
@IBOutlet var postcategorylabel: UILabel!
var detailView: Post?
var postId:String = ""
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
postIdlabel?.text = detailView?._documentId
posttitlelabel?.text = detailView?._postTitle
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destination.
// Pass the selected object to the new view controller.
}
*/
}
最佳答案
这种情况通常发生在您已经在 XIB 文件中设置 IBOutlet 并且您在代码中注释掉它的连接 socket 时。
在你的情况下，在你的 PostDetailViewController
// @IBOutlet var description: UILabel!
您已经评论了描述标签，但 IBOutlet 仍然连接在您的 XIB 文件中。
因此，查找您的 XIB 文件并检查事件的 IBOutlet 连接，并删除它以获取描述标签、清理、构建和运行。
希望对您有所帮助。
关于ios - 得到 NSUnknownKeyException' 的错误，原因 : setValue:forUndefinedKey: this class is not key value coding-compliant for the key description，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57751794/