Get all list of UIViewControllers in iOS Swift

Question

Is there any way to fetch all UIViewControllers in iOS Swift Project. I want to get array of all the UIViewControllers and check whether particular UIViewController exists or not.I have to just find the particular UIViewController exists or not in project.

Answer 1

You can do it with below code.

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate

if let viewControllers = appDelegate.window?.rootViewController?.presentedViewController
{
    // Array of all viewcontroller even after presented
}
else if let viewControllers = appDelegate.window?.rootViewController?.childViewControllers
{
    // Array of all viewcontroller after push                            
}

Swift 4.2 ( XCode 10 )

let appDelegate = UIApplication.shared.delegate as! AppDelegate

if (appDelegate.window?.rootViewController?.presentedViewController) != nil
{
    // Array of all viewcontroller even after presented
}
else if (appDelegate.window?.rootViewController?.children) != nil
{
    // Array of all viewcontroller after push
}

Answer 2

Here is an extension I made on the basis of prev answers

Uses Generics + Extension (🔸Swift 5.1)

/**
 * - Returns: ViewController of a class Kind
 * ## Examples: 
 * UIView.vc(vcKind: CustomViewController.self) // ref to an instance of CustomViewController
 */
 public static func vc<T: UIViewController>(vcKind: T.Type? = nil) -> T? {
     guard let appDelegate = UIApplication.shared.delegate, let window = appDelegate.window else { return nil }
     if let vc = window?.rootViewController as? T {
         return vc
     } else if let vc = window?.rootViewController?.presentedViewController as? T {
         return vc
     } else if let vc = window?.rootViewController?.children {
         return vc.lazy.compactMap { $0 as? T }.first
     }
     return nil
 }