CustomAgoraViewController.swift

override func viewDidLoad() {
   super.viewDidLoad()


   // Do any additional setup after loading the view.
   chatTableView = UITableView(frame: .zero)
   view.addSubview(chatTableView)


   chatTableView.delegate = self
   chatTableView.dataSource = self
   chatTableView.backgroundColor = UIColor.clear


   chatTableView.translatesAutoresizingMaskIntoConstraints = false


   chatTableView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
   chatTableView.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.4).isActive = true
   chatTableView.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.5).isActive = true


   chatTableView.register(UITableViewCell.self, forCellReuseIdentifier: "chatCell")
   chatTableView.keyboardDismissMode = .onDrag
   collectionView.keyboardDismissMode = .interactive


   let chatField = UITextField(frame: .zero)
   view.addSubview(chatField)
   chatField.delegate = self
   chatField.backgroundColor = UIColor.white


   chatField.translatesAutoresizingMaskIntoConstraints = false


   chatField.topAnchor.constraint(equalTo: chatTableView.bottomAnchor).isActive = true
   chatField.leftAnchor.constraint(equalTo: chatTableView.leftAnchor).isActive = true
   chatField.widthAnchor.constraint(equalTo: chatTableView.widthAnchor).isActive = true
   chatField.heightAnchor.constraint(equalToConstant: 40).isActive = true
   bottomConstraint = view.bottomAnchor.constraint(equalTo: chatField.bottomAnchor, constant: 110)
   bottomConstraint?.isActive = true


   NotificationCenter.default.addObserver(self, selector: #selector(ChatViewController.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
   NotificationCenter.default.addObserver(self, selector: #selector(ChatViewController.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}