无法将类型的值转换为 UINavigationController swift3
Could not cast value of type to UINavigationController swift3
我收到以下转换错误(当我单击模拟器 [NavigationController] 中的“+”按钮时)并且无法弄清楚原因。
我正在使用 Swift3。感谢您的帮助!
MainVC.swift
protocol AddTaskDelegate: class {
func saveTask(by controller: AddVC, with data: [String:String])
}
class MainVC: UIViewController {
// all tasks from the database
var tasks = [ToDoListTasks]()
@IBOutlet weak var table: UITableView!
// connect with Core Data
let managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
...
// prepare segue to send data
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "AddSegue" {
let navigationController = segue.destination as! UINavigationController
let childViewController = navigationController.topViewController as! AddVC
childViewController.delegate = self as! AddTaskDelegate
}
}
}
AddVC.swift
class AddVC: UIViewController {
weak var delegate: AddTaskDelegate?
...
请阅读错误信息。你是说
segue.destination as! UINavigationController
但是这个 segue 的目的地是不是 UINavigationController。
我收到以下转换错误(当我单击模拟器 [NavigationController] 中的“+”按钮时)并且无法弄清楚原因。 我正在使用 Swift3。感谢您的帮助!
MainVC.swift
protocol AddTaskDelegate: class {
func saveTask(by controller: AddVC, with data: [String:String])
}
class MainVC: UIViewController {
// all tasks from the database
var tasks = [ToDoListTasks]()
@IBOutlet weak var table: UITableView!
// connect with Core Data
let managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
...
// prepare segue to send data
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "AddSegue" {
let navigationController = segue.destination as! UINavigationController
let childViewController = navigationController.topViewController as! AddVC
childViewController.delegate = self as! AddTaskDelegate
}
}
}
AddVC.swift
class AddVC: UIViewController {
weak var delegate: AddTaskDelegate?
...
请阅读错误信息。你是说
segue.destination as! UINavigationController
但是这个 segue 的目的地是不是 UINavigationController。