[英]Swift delegation problem without storyboard and segue
我在另一個控制器中觸發一個控制器中的方法時遇到問題。 我以編程方式設置了所有元素(按鈕,視圖..),我也使用了NavigationController
。
我想在新用戶登錄或注冊時觸發fetchUsers()
方法,以便tableView使用當前正在填充Firebase的所有用戶重新加載其單元格。
問題是fetchUsersDelegate?.fetchUsers()
方法永遠不會被調用,因為loginController.fetchUsersDelegate = self
永遠不會設置為self,並且始終保持為零。
所以我的問題是我應該如何正確設置fetchUsersDelegate
?
頭等艙
class LoginController: UIViewController {
var fetchUsersDelegate: FetchUsersDelegate?
lazy var loginRegisterButton: UIButton = {
let button = UIButton()
button.backgroundColor = UIColor(r: 80, g: 101, b: 161)
button.translatesAutoresizingMaskIntoConstraints = false
button.setTitle("Register", for: .normal)
button.setTitleColor(UIColor.white, for: .normal)
button.titleLabel?.font = UIFont.boldSystemFont(ofSize: 16)
button.layer.cornerRadius = 25
button.layer.masksToBounds = true
button.addTarget(self, action: #selector(handleLoginRegister), for: .touchUpInside)
return button
}()
@objc func handleLoginRegister(){
if loginRegisterSegmentedControl.selectedSegmentIndex == 0 {
handleLogin()
} else {
handleRegister()
}
}
func handleLogin() {
guard let email = emailTextField.text, let password = passwordTextField.text else {
print("Registration form is not valid")
return
}
Auth.auth().signIn(withEmail: email, password: password) { (user, error) in
if error != nil {
print(error!)
return
}
print("Sucessfully logged in")
self.dismiss(animated: true, completion: nil)
}
self.fetchUsersDelegate?.fetchUsers()
}
二等
class UsersController: UITableViewController, FetchUsersDelegate{
let cellID = "cellID"
var users = [User]()
let loginController = LoginController()
override func viewDidLoad() {
super.viewDidLoad()
loginController.fetchUsersDelegate = self
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Logout", style: .plain, target: self, action: #selector(handleLogout))
checkIfUserIsLoggedIn()
}
func fetchUsers(){
Database.database().reference().child("users").observe(.childAdded, with: { (DataSnapshot) in
if let dictionary = DataSnapshot.value as? [String: AnyObject]{
let user = User()
user.name = dictionary["name"] as? String
user.email = dictionary["email"] as? String
self.users.append(user)
// if we call just tableView.reloadData the app will crash, insead we need to call it inside
// DispatchQueue.main.async
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
}, withCancel: nil)
}
協議
protocol FetchUsersDelegate {
func fetchUsers()
}
*編輯:
這是我在AppDelegate類中設置rootViewController的方式
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
FirebaseApp.configure()
window = UIWindow(frame: UIScreen.main.bounds)
window?.makeKeyAndVisible()
window?.rootViewController = UINavigationController(rootViewController: UsersController())
return true
}
這就是我目前使用LoginController的方式,如果有幫助,則handleLogout()方法位於UsersController內。
@objc func handleLogout(){
do{
try Auth.auth().signOut()
} catch let logoutError{
print(logoutError)
}
let loginController = LoginController()
present(loginController, animated: true, completion: nil)
}
這條線
let loginController = LoginController()
是問題,它與所呈現的vc無關,並且是一個新的單獨實例,因此當您呈現用戶時
let user = UsersController()
self.fetchUsersDelegate = user
present// add child// user
如果用戶可以同時登錄用戶表存在於screen中,那么我希望它是菜單列表或子vc
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