How to Organize my ViewScreens on Swift Programmatic UI - swift

Question

I'm learning Programmatic UI and am a little bit obsessed with clean code.
I'm currently building a TabBarVC so that I can manage all of my VC's but I get an error message while doing this.
import UIKit
class MainTabBarVC: UITabBarController {
let firstVC = FirstVC()
let secondVC = SecondVC()
let firstNavVC = UINavigationController(rootViewController: firstVC) // Cannot use instance member 'firstVC' within property initializer; property initializers run before 'self' is available
let secondNavVC = UINavigationController(rootViewController: secondVC) // Cannot use instance member 'secondVC' within property initializer; property initializers run before 'self' is available
let viewControllers = [firstNavVC, secondNavVC]
override func viewDidLoad() {
super.viewDidLoad()
self.setupViews()
}
func setupViews() {
// Nav Configs
self.firstVC.view.backgroundColor = .systemBackground
self.firstVC.navigationItem.title = "First Nav"
self.secondVC.view.backgroundColor = .systemBackground
self.secondVC.navigationItem.title = "Second Nav"
// Tab Configs
self.firstNavVC.tabBarItem.title = "First TAB"
self.secondNavVC.tabBarItem.title = "Second TAB"
}
}
I know if I put firtNavVC, secondNavVC, and viewcontrollers inside the setupViews it is gonna work but I don't like it when one function has too many lines of codes especially when it gets bigger.
So except for my question, are there any extension or enum functions that I can easily manage all of my UINavigationController, UITabBarController, and UIViewController such as enumeration that can call the function whenever I need to call or add a new VC.

Answer 1

You could change your lets into lazy vars.
class MainTabBarVC: UITabBarController {
lazy var firstVC = FirstVC()
lazy var secondVC = SecondVC()
lazy var firstNavVC = UINavigationController(rootViewController: firstVC)
lazy var secondNavVC = UINavigationController(rootViewController: secondVC)
lazy var viewControllers = [firstNavVC, secondNavVC]
override func viewDidLoad() {
super.viewDidLoad()
self.setupViews()
}
However, I think your impulse to maintain instance property references to all these view controllers is mistaken. What I would do is just move the lets into setupViews. You don't need a permanent reference to any of these objects; you just need to create them, configure them, and assign the view controllers as children of your tab bar controller (your code is missing that crucial step, by the way).