Custom init of UIViewController from storyboard

Question

I tried finding some relevant questions but couldn\'t get anything, hope someone can help.

I set up some UIViewController\'s on a storyboard. I then want to load one

Answer 1

Below are two helpers, one is a Storyboard enum, add each and every storyboard in your project as a case under this enum. The name must match the {storyboard_name}.storyboard file. Each view controller in your storyboard should have its storyboard identifier set to the name of the class. This is pretty standard practice.

import UIKit

public enum Storyboard: String {
    case Main
    case AnotherStoryboard
    //case {storyboard_name}

    public func instantiate(_ viewController: VC.Type) -> VC {
        guard
            let vc = UIStoryboard(name: self.rawValue, bundle: nil)
                .instantiateViewController(withIdentifier: VC.storyboardIdentifier) as? VC
            else { fatalError("Couldn't instantiate \(VC.storyboardIdentifier) from \(self.rawValue)") }

        return vc
    }

    public func instantiateInitialVC() -> UIViewController {

        guard let vc = UIStoryboard(name: self.rawValue, bundle: nil).instantiateInitialViewController() else {
            fatalError("Couldn't instantiate initial viewcontroller from \(self.rawValue)")
        }

        return vc
    }
}

extension UIViewController {
    public static var defaultNib: String {
        return self.description().components(separatedBy: ".").dropFirst().joined(separator: ".")
    }

    public static var storyboardIdentifier: String {
        return self.description().components(separatedBy: ".").dropFirst().joined(separator: ".")
    }
}

Here is how you can instantiate from storyboard with a value set in your view controller. Here is the magic:

import UIKit

class DetailViewController: UIViewController {

    var objectID : Int!
    var objectDetails: ObjectDetails = ObjectDetails()        

    internal static func instantiate(with objectID: Int) -> DetailViewController {

        let vc = Storyboard.Main.instantiate(DetailViewController.self)
        vc.objectID = objectID
        return vc
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        if((objectID) != nil){
            // In this method I use to make a web request to pull details from an API
            loadObjectDetails()
        }
    }
}

(Architecture influenced/copies Kickstarter's open source iOS project)