iOS (Swift) - Array of UIViewControllers

Question

I have an array UIButtons that have a unique tag value. When a given button is pressed, I want to load and present a UIViewController that is also stored in an array of equal length.

The UIViewControllers to be presented are subclasses of a subclass of UIViewController:

class AViewController: UIViewController {}
class BViewController: AViewController {}
class CViewController: AViewController {}
class DViewController: AViewController {}
// ... etc.

I've tried storing the array of AViewController subclasses using the following:

private var array: [AViewController] = [BViewController.self, CViewController.self, DViewController.self]

but I get the error Cannot convert value of type '[BViewController].Type' to specified type '[AViewController]' for the first element.

I will then present BViewController (for instance) using the following:

let ViewController = array[button.tag].self
var viewController: AViewController
viewController = ViewController.init()
viewController.transitioningDelegate = self
viewController.modalPresentationStyle = .custom
present(viewController, animated: true)

Please let me know if this is the incorrect thought process for doing something like this please and thanks for any help.

Shehata Gamal · Accepted Answer · 2018-12-20 09:39:08Z

6

You need instances

private var array: [AViewController] = [BViewController(), CViewController(), DViewController()]

if the vcs are in IB , then you would do

let b = self.storyboard!.instantiateViewController(withIdentifier: "bID") as! BViewController
let c = self.storyboard!.instantiateViewController(withIdentifier: "cID") as! CViewController 
let d = self.storyboard!.instantiateViewController(withIdentifier: "dID") as! DViewController

Then

array = [b,c,d]

edited Dec 20, 2018 at 9:39

answered Dec 20, 2018 at 9:33

Shehata Gamal

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4 Comments

ajrlewis Over a year ago

Thanks for your suggestion. Does this not use a a lot of memory as I have ~10 subclasses of AViewController and each is fairly hefty in size? Thanks again.

Shehata Gamal Over a year ago

yes, it's a heavy work , you can make a var to keep track of the current index , then load the vc when you need to without making that array or make it an array of storyboard ids

ajrlewis Over a year ago

Thanks. Im writing this programmatically so no storyboards or segues. Is this any more work than using segues? A lot of the UIButtons in the view controllers do get initialised until the viewDidLoad function is called ...

Shehata Gamal Over a year ago

you can make a link on the fly such as an Int switch in a function that takes index and return vc like if 1 return BViewController and so on away to make them created when you need to

Kunal Parikh · Accepted Answer · 2020-04-21 05:57:15Z

0

lazy var VCArray :[UIViewController] = {
    return [VCinst(name: "firstVC"),VCinst(name: "secondVC"), VCinst(name: "thirdVC")]
}()

func VCinst(name:String) -> UIViewController {
       return UIStoryboard(name: "Main", bundle: nil).instantiateViewController(identifier: name)
}

answered Apr 21, 2020 at 5:57

Kunal Parikh

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1 Comment

Jaimil Patel Over a year ago

Hope It will solve issue but please add explaination of your code with it so user will get perfect understanding which he/she really wants.

iPhoneDeveloper · Accepted Answer · 2022-08-17 06:37:07Z

0

Alternate answer if you want to store array of view controllers as a constant.

 struct AppConstant {

       static let yourViewControllers: [AnyClass] = [AViewController.self, 
            BViewController.self, CViewController.self]
}

answered Aug 17, 2022 at 6:37

iPhoneDeveloper

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