Tab bar controllers with coordinators - ios

Question

I use coordinator pattern in my app, but I have problem with instantiate view controllers. The problem is that I use different module for each tab bar controller.
So far I've used this approach
protocol Storyboarded {
static func instantiate() -> Self
}
extension Storyboarded where Self: UIViewController {
static func instantiate() -> Self {
let id = String(describing: self)
let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
return storyboard.instantiateViewController(identifier: id) as! Self
}
}
And during creation tab bar coordinator:
class MainTabBarController: UITabBarController, Storyboarded {
let main = MainCoordinator(navigationController: UINavigationController())
let calendar = CalendarCoordinator(navigationController: UINavigationController())
let chart = ChartCoordinator(navigationController: UINavigationController())
let profile = ProfileCoordinator(navigationController: UINavigationController())
override func viewDidLoad() {
super.viewDidLoad()
main.start()
calendar.start()
chart.start()
profile.start()
viewControllers = [main.navigationController, calendar.navigationController, chart.navigationController, profile.navigationController]
}
My all view controllers conform to Storyboarded Protocol:
class HomeTableViewController: UIViewController, Storyboarded {}
And coordinator for each tab bar controller looks like this
class MainCoordinator: Coordinator {
var childCoordinators = [Coordinator]()
var navigationController: UINavigationController
init(navigationController: UINavigationController) {
self.navigationController = navigationController
}
func start() {
let vc = HomeTableViewController.instantiate()
vc.tabBarItem = UITabBarItem(title: "Home", image: UIImage(systemName: "home"), tag: 0)
navigationController.pushViewController(vc, animated: false)
}
}
The problem is that other tab bar controllers belong to others storyboard, not only "Main". Using instantiate() from protocol causes error. I wonder how to create protocol extension where I can initialise ViewControllers with different storyboard names, not only "Main".

Answer 1

Try add this:
protocol Storyboarded {
static var storyboardName: String { get }
static func instantiate() -> Self
}
extension Storyboarded where Self: UIViewController {
static var storyboardName: String {
"Main" // Default implementation
}
static func instantiate() -> Self {
let id = String(describing: self)
let storyboard = UIStoryboard(name: Self.storyboardName, bundle: Bundle.main)
return storyboard.instantiateViewController(identifier: id) as! Self
}
}
Now you can do:
extension HomeTableViewController: Storyboarded {
class var storyboardName: String {
"Home" // Other storyboard name here, overrides default implementation
}
}