Instantiate and Present a viewController in Swift

Question

Issue

I started taking a look of the new Swift on Xcode 6, and I tried some demo projects and tutorials. Now I am stuck at:

Instantiating and then presenting a viewController from a specific storyboard

Objective-C Solution

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"myStoryboardName" bundle:nil];
UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"myVCID"];
[self presentViewController:vc animated:YES completion:nil];

How to achieve this on Swift?

Answer 1

I would like to suggest a much cleaner way. This will be useful when we have multiple storyboards

1.Create a structure with all your storyboards

struct Storyboard {
      static let main = "Main"
      static let login = "login"
      static let profile = "profile" 
      static let home = "home"
    }

2. Create a UIStoryboard extension like this

extension UIStoryboard {
  @nonobjc class var main: UIStoryboard {
    return UIStoryboard(name: Storyboard.main, bundle: nil)
  }
  @nonobjc class var journey: UIStoryboard {
    return UIStoryboard(name: Storyboard.login, bundle: nil)
  }
  @nonobjc class var quiz: UIStoryboard {
    return UIStoryboard(name: Storyboard.profile, bundle: nil)
  }
  @nonobjc class var home: UIStoryboard {
    return UIStoryboard(name: Storyboard.home, bundle: nil)
  }
}

Give the storyboard identifier as the class name, and use the below code to instantiate

let loginVc = UIStoryboard.login.instantiateViewController(withIdentifier: "\(LoginViewController.self)") as! LoginViewController

Answer 2

This link has both the implementations:

Swift:

let viewController:UIViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("ViewController") as UIViewController
self.presentViewController(viewController, animated: false, completion: nil)

Objective C

UIViewController *viewController = [[UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil] instantiateViewControllerWithIdentifier:@"ViewController"];

This link has code for initiating viewcontroller in the same storyboard

/*
 Helper to Switch the View based on StoryBoard
 @param StoryBoard ID  as String
*/
func switchToViewController(identifier: String) {
    let viewController = self.storyboard?.instantiateViewControllerWithIdentifier(identifier) as! UIViewController
    self.navigationController?.setViewControllers([viewController], animated: false)

}

Answer 3

akashivskyy's answer works just fine! But, in case you have some trouble returning from the presented view controller, this alternative can be helpful. It worked for me!

Swift:

let storyboard = UIStoryboard(name: "MyStoryboardName", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("someViewController") as! UIViewController
// Alternative way to present the new view controller
self.navigationController?.showViewController(vc, sender: nil)

Obj-C:

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MyStoryboardName" bundle:nil];
UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"someViewController"];
[self.navigationController showViewController:vc sender:nil];

Answer 4

No matter what I tried, it just wouldn't work for me - no errors, but no new view controller on my screen either. Don't know why, but wrapping it in timeout function finally made it work:

DispatchQueue.main.asyncAfter(deadline: .now() + 0.0) {
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let controller = storyboard.instantiateViewController(withIdentifier: "TabletViewController")
    self.present(controller, animated: true, completion: nil)
}

Answer 5

It all is a matter of the new syntax, functionality hasn't changed:

// Swift 3.0

let storyboard = UIStoryboard(name: "MyStoryboardName", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "someViewController")
self.present(controller, animated: true, completion: nil)

If you're having problems with init(coder:), please refer to EridB's answer.

Answer 6

Swift 4:

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let yourVC: YourVC = storyboard.instantiateViewController(withIdentifier: "YourVC") as! YourVC