Swift - UIKit - UIViewController

UIViewController.swift

import UIKit

extension UIViewController {
    /// Print through console the current view controllers hierarchy.
    func printHierarchy() {
        let log = { (str: String) in
            print("*** *** ***   *** *** ***   *** *** ***")
            print(str)
            print("*** *** ***   *** *** ***   *** *** ***")
        }

        var rootVC: UIViewController?

        if #available(iOS 15, *) {
            rootVC = UIApplication.shared.connectedScenes
                .compactMap({ $0 as? UIWindowScene })
                .flatMap({ $0.windows })
                .first(where: { $0.isKeyWindow })?.rootViewController
        } else if #available(iOS 13, *) {
            rootVC = UIApplication.shared.windows.first(where: { $0.isKeyWindow })?.rootViewController
        } else {
            rootVC = UIApplication.shared.keyWindow?.rootViewController
        }

        guard let rootVC = rootVC else {
            log("RootViewController not found!")
            return
        }

        log("\(rootVC.value(forKey: "_printHierarchy") ?? "Hierarchy not found!")")
    }
}