Hi I'm kind of new to Swift and I can't figure this out. I am trying to create a sign out button that would take user to the login page. I used the following two methods but the first one doesn't do anything and the second one is throwing Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value and it refers to the code with the customButton:
//this one doesn't do anything
#objc func SignOut(){
let vc = self.storyboard?.instantiateViewController(identifier: "LoginViewController") as! LoginViewController
let appDelegate = UIApplication.shared.delegate
appDelegate?.window??.rootViewController = vc
}
//this one is throwing an error
let vc = CustomViewController()
self.present(vc, animated: true, completion: nil)
//the Fatal error refers to this code
override func viewDidLoad() {
super.viewDidLoad()
self.customButton.addTarget(self, action: #selector(customButtonPressed), for: .touchUpInside)
}
Also, I was wondering if AppDelegate is the right approach or if I should use SceneDelegate. Any help would be greatly appreciated.
Try to do this
#objc func SignOut(){
let vc = self.storyboard?.instantiateViewController(identifier: "LoginViewController") as! LoginViewController
self.view.window?.rootViewController = vc
}
let vc = self.storyboard?.instantiateViewController(identifier: "LoginViewController") as! LoginViewController
vc.modalPresentationStyle = .fullScreen
self.present(vc, animated: true, completion: nil)
Please make sure the identifier is matching the one inside storyboard for this viewController
I'm trying the make a function that receives a name (String) of a View Controller and then presents that View Controller modally. Example:
func presentViewControllerModally(newViewControllerName: String){
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "\(newViewControllerName)_Identifier") as! newViewControllerName
self.present(newViewController, animated: false, completion: nil)
}
But I can't make the as! newViewControllerName to work as if the newViewControllerName is the type of the newViewControllerName and not the object itself.
You don’t have to downcast controller to your custom subclass. You can just present UIViewController.
If you have to get the real viewController type in return, just use generics to do this.
func presentViewControllerModally<T: UIViewController>(newViewControllerName: String) -> T? {
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
if let newViewController = storyBoard.instantiateViewController(withIdentifier: "\(newViewControllerName)_Identifier") as? T {
self.present(newViewController, animated: false, completion: nil)
return newViewController
}
return nil
}
Then call
let myVC: MyVController = presentViewControllerModally(newViewControllerName: "MyVC")
If you don't need the right type but just UIViewController, you don't need a cast.
the error I'm receiving that I can't seem to fix is
Terminating app due to uncaught exception
'NSInvalidArgumentException', reason: 'Could not find a storyboard
named 'MainTabController' in bundle NSBundle
the app will build and the login screen will display but crashes immediately after with the error stated above.
I have tried all of the following from other post similar to this and have had no luck.
Removing the reference to the storyboard in the info.plist file. When I do this the app does start but I get a black screen as it doesn't load the storyboard.
Fiddle with the Target Membership Main.storyboard.
Remove the storyboard from the project, clean, run and then adding the storyboard back again.
Uninstall Xcode, reinstall Xcode.
Deleting the Derived Data folder.
the problem appears to be with my presentMainScreen() method
func presentMainScreen(){
let mainstoryboard = UIStoryboard(name: "MainTabController", bundle: nil)
let mainTabController = mainstoryboard.instantiateViewController(withIdentifier: "MainTabController") as! MainTabController
mainTabController.selectedViewController = mainTabController.viewControllers?[1]
//let storyboard:UIStoryboard = UIStoryboard(name:"Main", bundle:nil)
//let loggedInVC:LoggedInVC = storyboard.instantiateViewController(withIdentifier: "LoggedInVC") as! LoggedInVC
//self.present(loggedInVC, animated: true, completion: nil)
}
if I comment out the mainTabController lines the app will work perfectly, also if I uncomment the loggedInVC lines and with the mainTabController lines commented out it works perfectly as well.
any suggestions are greatly appreciated.
below is my entire ViewController.swift code and a screenshot of my workspace
workspace
ViewController.swift
import UIKit
import FirebaseAuth
class ViewController: UIViewController {
#IBOutlet weak var emailTextField: UITextField!
#IBOutlet weak var passwordTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(_ animated: Bool) {
if Auth.auth().currentUser != nil {
print("success")
self.presentMainScreen()
}
}
#IBAction func creatAccountTapped(_ sender: Any) {
if let email = emailTextField.text, let password = passwordTextField.text {
Auth.auth().createUser(withEmail: email, password: password, completion:{ user, error in
if let firebaseError = error {
print(firebaseError.localizedDescription)
return
}
print("success")
self.presentMainScreen()
})
}
}
#IBAction func loginButtonTapped(_ sender: Any) {
if let email = emailTextField.text, let password = passwordTextField.text {
Auth.auth().signIn(withEmail: email, password: password, completion: { (user, error) in
if let firebaseError = error {
print(firebaseError.localizedDescription)
return
}
print("success")
self.presentMainScreen()
})
}
}
func presentMainScreen(){
let mainstoryboard = UIStoryboard(name: "MainTabController", bundle: nil)
let mainTabController = mainstoryboard.instantiateViewController(withIdentifier: "MainTabController") as! MainTabController
mainTabController.selectedViewController = mainTabController.viewControllers?[1]
//let storyboard:UIStoryboard = UIStoryboard(name:"Main", bundle:nil)
//let loggedInVC:LoggedInVC = storyboard.instantiateViewController(withIdentifier: "LoggedInVC") as! LoggedInVC
//self.present(loggedInVC, animated: true, completion: nil)
}
}
What is the name of your storyboard? Is it MainTabController.storyboard or Main.storyboard?
You are trying to load a storyboard named "MainTabController":
let mainstoryboard = UIStoryboard(name: "MainTabController", bundle: nil)
But previously you called it Main.storyboard:
Fiddle with the Target Membership Main.storyboard.
Also if the main tab controller is in the same storyboard as your login view controller then you can try to use this:
let mainTabController = self.storyboard.instantiateViewController(withIdentifier: "MainTabController")
Your story board is named as Main.storyboard. MainTabController is the controller in the Main storyboard.
let mainstoryboard = UIStoryboard(name: "Main", bundle: nil)
let mainTabController = mainstoryboard.instantiateViewController(withIdentifier: "MainTabController") as! MainTabController
mainTabController.selectedViewController = mainTabController.viewControllers?[1]
let mainstoryboard = UIStoryboard(name: "MainTabController", bundle: nil)
Your storyboard is named "Main"
let storyboard = self.storyboard!
let storyCtrl = storyboard.instantiateViewControllerWithIdentifier("LoginTableViewController")
self.presentViewController(storyCtrl, animated: true, completion: { _ in })
I am getting this error : - fatal error: unexpectedly found nil while unwrapping an Optional value.
Swift 3.0 Use the following code to load controller from story board
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let viewController = storyboard.instantiateViewController(withIdentifier: "viewController")
self.presentViewController(viewController, animated: true, completion: { _ in })
Main = name of the storyboard
viewController = the name of the view controller identifier
I programatically have multiple View Controllers in an iOS Swift Project. I do not have the storyboards and would like to avoid them if possible. Is there a way to switch to another viewcontroller.swift file (We will call it view2.swift) and have it be part of a function that a button calls?I have tried the following:
let storyboard: UIStoryboard = UIStoryboard(name: "myTabBarName", bundle: nil)
let vc: UIViewController = storyboard.instantiateViewControllerWithIdentifier("myVCID") as UIViewController
self.presentViewController(vc, animated: true, completion: nil)
The above works with storyboards, but I want another view2.swift to be called. Can this be done?
Try this:
let vc = ViewController() //change this to your class name
self.presentViewController(vc, animated: true, completion: nil)
With Swift3:
self.present(vc, animated: true, completion: nil)
For those getting blank/black screens this code worked for me.
let vc = self.storyboard?.instantiateViewController(withIdentifier: myVCID) as! myVCName
self.present(vc, animated: true, completion: nil)
To set the "Identifier" to your VC just go to identity inspector for the VC in the storyboard. Set the 'Storyboard ID' to what ever you want to identifier to be. Look at the image below for reference.
For reference, because this question is one of the first Google result.
Breaking change in Swift 3:
The method presentViewController is replaced by the method present.
You can use it like the old one:
self.present(viewControllerToPresent, animated: true, completion: nil)
Example to open the camera:
let imagePicker = UIImagePickerController()
imagePicker.delegate = self
imagePicker.sourceType = UIImagePickerControllerSourceType.camera
imagePicker.allowsEditing = false
self.present(imagePicker, animated: true, completion: nil)
Swift 3 and Swift 4
let vc = self.storyboard?.instantiateViewController(withIdentifier: "idMyViewControllerName") as! MyViewControllerName
self.present(vc, animated: true, completion: nil)
For me, I had two views in two separate nav controllers. I had to use a combination of the above.
var vc = self.storyboard?.instantiateViewControllerWithIdentifier("WelcomeViewController") as! WelcomeViewController
var navigationController = UINavigationController(rootViewController: vc)
self.presentViewController(navigationController, animated: true, completion: nil)
Swift 3.x
let secondVC = self.storyboard?.instantiateViewController(withIdentifier: "VC-ID" as! yourViewController
let navigationVC = UINavigationController(rootViewController: secondVC)
self.present(navigationVC, animated: true, completion: nil)
Using Swift 2.1+
let vc = self.storyboard?.instantiateViewControllerWithIdentifier("settingsVC") as! SettingsViewController
self.presentViewController(vc, animated: true, completion: nil)
Solved the black screen by adding a navigation controller and setting the second view controller as rootVC.
let vc = ViewController()
var navigationController = UINavigationController(rootViewController: vc)
self.presentViewController(navigationController, animated: true, completion: nil
Just use this : Make sure using nibName otherwise preloaded views of xib will not show :
var vc : ViewController = ViewController(nibName: "ViewController", bundle: nil) //change this to your class name
self.presentViewController(vc, animated: true, completion: nil)
You don't need to instantiate the ViewController in Storyboard just to get present() ViewController to work. That's a hackish solution.
If you see a black/blank screen when presenting a VC, it might be because you're calling present() from viewDidLoad() in the First/RootViewController, but the first View isn't ready yet.
Call present() from viewDidAppear to fix this, i.e.:
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let yourVC = YourViewController()
self.present(yourVC, animated: true, completion: nil)
}
Once any "View" has appeared in your App, you can start calling present() from viewDidLoad().
Using UINavigationController (as suggested in an answer) is another option, but it might be an overkill to solve this issue. You might end up complicating the user flow. Use the UINavigationController based solution only if you want to have a NavigatonBar or want to return to the previous view controller.
You can use below code :
var vc = self.storyboard?.instantiateViewControllerWithIdentifier("YourViewController") as! YourViewController;
vc.mode_Player = 1
self.presentViewController(vc, animated: true, completion: nil)
Another possibility is that you do not have the XIB included in your Build target (which is what happened to me).
This could happen if you have a different target for Dev, Test & Release Builds (which you should have anyway).
I had a similar issue but in my case, the solution was to dispatch the action as an async task in the main queue
DispatchQueue.main.async {
let vc = self.storyboard?.instantiateViewController(withIdentifier: myVCID) as! myVCName
self.present(vc, animated: true, completion: nil)
}
It's already answered. But adding one more thing while presenting a UIViewController, If anyone is trying to add UIModalPresentationStyle :
if directly presenting the UIViewController as fullScreen:
let viewController = UIViewController()
viewController.modalPresentationStyle = .fullScreen
self.present(viewController, animated: true)
If there is UINavigationController with root view controller as UIViewController:
let viewController = UIViewController()
let navigationController = UINavigationController(rootViewController: viewController)
navigationController.modalPresentationStyle = .fullScreen
self.present(navigationController, animated: true)
More helpful answers:
Presenting modal in iOS 13 fullscreen
You can use code:
if let vc = self.storyboard?.instantiateViewController(withIdentifier: "secondViewController") as? secondViewController {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
appDelegate.window?.rootViewController = vc
}