如何修复 Table Viewcontroller 上的时间延迟？

Question

I created a note app. The NotizenViewControllerArchive save the note and with the NotizenViewControllerAdd can you add new notes.

There is a third Viewcontroller, on this I can visit the other two views, but after I switched (with a button) from the third Viewcontroller to NotizenViewControllerArchive there is a time delay, a short moment who I can't see my notes how can I fix that so the notes shows immediately?.

I tried for a long time to fix it but I don't know how, I put the whole code in because I don't know where the problem is. Thanks for your help

NotizenViewControllerArchive

import UIKit

class NotizenViewControllerArchive: UIViewController, UITableViewDelegate, UITableViewDataSource {

  @IBOutlet weak var table: UITableView!

  var items:[String] = []
  func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return items.count
  }


  func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell(style: UITableViewCell.CellStyle.default, reuseIdentifier: "Cell")

    let backgroundView = UIView()
    backgroundView.backgroundColor = UIColor.init(red: 48/255, green: 173/255, blue: 99/255, alpha: 1)
    cell.selectedBackgroundView = backgroundView

    cell.textLabel?.text = items[indexPath.row]
    return cell

  }

  override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
  }

  override func viewDidAppear(_ animated: Bool) {
    let itemObject = UserDefaults.standard.object(forKey: "items")

    if let tempItems = itemObject as? [String] {
      items = tempItems
    }

    table.reloadData()
  }


  func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == UITableViewCell.EditingStyle.delete {

      items.remove(at: indexPath.row)
      tableView.reloadData()
      UserDefaults.standard.set(items, forKey: "items")

    }
  }
}

NotizenViewControllerAdd

import UIKit

class NotizenViewControllerAdd: UIViewController, UITextFieldDelegate {

  @IBOutlet weak var itemTextField: UITextField!

  @IBAction func ad(_ sender: UIButton) {
    let itemObject = UserDefaults.standard.object(forKey: "items")

    var items:[String]

    if let tempItems = itemObject as? [String] {
      items = tempItems
      items.append(itemTextField.text!)
      print("items")
    } else {
      items = [itemTextField.text!]
    }

    UserDefaults.standard.set(items, forKey: "items")
    itemTextField.text = ""
  }

  override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    self.view.endEditing(true)
  }

  func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    return true
  }

  override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
  }
}

Answer 1

Try moving the code from viewDidAppear to viewWillAppear or viewDidLoad on your NotizenViewControllerArchive. The code inside the viewDidAppear will only execute after the view is already on screen for the user (hence the name)