[ios] How to Navigate from one View Controller to another using Swift

I'd like to navigate from one view controller to another. How can I convert the following Objective-C code into Swift?

UIViewController *viewController = [[self storyboard] instantiateViewControllerWithIdentifier:@"Identifier"];
UINavigationController *navi = [[UINavigationController alloc] initWithRootViewController:viewController];
[self.navigationController pushViewController:navi animated:YES];

Swift 4

You can switch the screen by pushing navigation controller first of all you have to set the navigation controller with UIViewController

let vc = self.storyboard?.instantiateViewController(withIdentifier: "YourStoryboardID") as! swiftClassName

self.navigationController?.pushViewController(vc, animated: true)

let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let home = storyBoard.instantiateViewController(withIdentifier: "HOMEVC") as! HOMEVC
navigationController?.pushViewController(home, animated: true);

Swift 5

Use Segue to perform navigation from one View Controller to another View Controller:

performSegue(withIdentifier: "idView", sender: self)

This works on Xcode 10.2.

In Swift 4.1 and Xcode 10

Here AddFileViewController is second view controller.

Storyboard id is AFVC

let next = self.storyboard?.instantiateViewController(withIdentifier: "AFVC") as! AddFileViewController
self.present(next, animated: true, completion: nil)

//OR

//If your VC is DashboardViewController
let dashboard = self.storyboard?.instantiateViewController(withIdentifier: "DBVC") as! DashboardViewController
self.navigationController?.pushViewController(dashboard, animated: true)

If required use thread.

Ex:

DispatchQueue.main.async { 
    let next = self.storyboard?.instantiateViewController(withIdentifier: "AFVC") as! AddFileViewController
    self.present(next, animated: true, completion: nil) 
}

If you want move after some time.

EX:

//To call or execute function after some time(After 5 sec)
DispatchQueue.main.asyncAfter(deadline: .now() + 5.0) {
    let next = self.storyboard?.instantiateViewController(withIdentifier: "AFVC") as! AddFileViewController
    self.present(next, animated: true, completion: nil) 
} 

In swift 4.0

var viewController: UIViewController? = storyboard().instantiateViewController(withIdentifier: "Identifier")
var navi = UINavigationController(rootViewController: viewController!)
navigationController?.pushViewController(navi, animated: true)

In my experience navigationController was nil so I changed my code to this:

let next = self.storyboard?.instantiateViewControllerWithIdentifier("DashboardController") as! DashboardController
self.presentViewController(next, animated: true, completion: nil)

Don't forget to set ViewController StoryBoard Id in StoryBoard -> identity inspector

Swift 3

let secondviewController:UIViewController =  self.storyboard?.instantiateViewController(withIdentifier: "StoryboardIdOfsecondviewController") as? SecondViewController

self.navigationController?.pushViewController(secondviewController, animated: true)

In swift 3

let nextVC = self.storyboard?.instantiateViewController(withIdentifier: "NextViewController") as! NextViewController        
self.navigationController?.pushViewController(nextVC, animated: true)

In AppDelegate you can write like this...

var window: UIWindow?

fileprivate let navigationCtrl = UINavigationController()

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    self.createWindow()

    self.showLoginVC()

    return true
}

func createWindow() {
    let screenSize = UIScreen.main.bounds
    self.window = UIWindow(frame: screenSize)
    self.window?.backgroundColor = UIColor.white
    self.window?.makeKeyAndVisible()
    self.window?.rootViewController = navigationCtrl
}

func showLoginVC() {
    let storyboardBundle = Bundle.main
    // let storyboardBundle = Bundle(for: ClassName.self) // if you are not using main application, means may be you are crating a framework or library you can use this statement instead
    let storyboard = UIStoryboard(name: "LoginVC", bundle: storyboardBundle)
    let loginVC = storyboard.instantiateViewController(withIdentifier: "LoginVC") as! LoginVC
    navigationCtrl.pushViewController(loginVC, animated: false)
}

SWIFT 3.01

let secondViewController = self.storyboard?.instantiateViewController(withIdentifier: "Conversation_VC") as! Conversation_VC
self.navigationController?.pushViewController(secondViewController, animated: true)

let objViewController = self.storyboard?.instantiateViewController(withIdentifier: "ViewController") as! ViewController
self.navigationController?.pushViewController(objViewController, animated: true)

If you don't want the back button to appear (which was my case, because I wanted to present after a user logged in) here is how to set the root of the nav controller:

let vc = self.storyboard?.instantiateViewControllerWithIdentifier("YourViewController") as! YourViewController
        let navigationController = UINavigationController(rootViewController: vc)
        self.presentViewController(navigationController, animated: true, completion: nil)