Swift、iOS：如何从具体类型中获取多态和解耦协调器

Question

我有这些协议：

protocol Coordinator {
    var rootViewController: UIViewController { get set }
    func start()
}

protocol UIViewControllerFactory {
    func mainViewController() -> UIViewController
}

我创建了一个符合此协议的MainCoordinator并传递了一个工厂，该工厂允许我将协调器与创建和捕获具体类型分离，因此它可以是多态的，并且可以与UIViewController的更多实现一起使用，如rootViewControllers和mainMenuViewController所示以下：

class MainCoordinator: Coordinator {
    var rootViewController: UIViewController
    let factory: UIViewControllerFactory 
    
    init(rootViewController: UIViewController, factory: UIViewControllerFactory) {
        self.rootViewController = rootViewController
    }
    
    start() {
        guard let mainVC = factory.mainViewController() as? MainViewController, let rootViewController = rootViewController as? UINavigationViewController  else { return }
        
        mainVC.delegate = self
        rootViewController.push(mainVC, animated: true)
    }

如您所见，虽然我创建了协调器来接受 UIViewController 的任何子类，但它在开始时已将 function 耦合到 UIViewController 的具体实现：MainViewController。

所以我的问题是如何将它与 MainViewController 分离并使其更具多态性？

Answer 1

您可以在工厂 function 中将协调器作为参数类型传递，并在创建 controller 实例时直接在工厂 function 中设置delegate 。 这样您就不必从工厂类中显式公开 controller type 。

我想出了以下方法。

protocol Coordinator {
    var rootViewController: UIViewController { get set }
    func start()
}

protocol UIViewControllerFactory {
    func getViewController(delegateType:CoordinatoreTypes,delegateObject:Coordinator) -> UIViewController?
}

class MainCoordinator: Coordinator {
    var rootViewController: UIViewController
    let factory: UIViewControllerFactory
    
    init(rootViewController: UIViewController, factory: UIViewControllerFactory) {
        self.rootViewController = rootViewController
        self.factory = factory
    }
    
    func start() {
        guard let controller = factory.getViewController(delegateType: .MainCoordinator, delegateObject: self),let rootViewController = rootViewController as? UINavigationViewController else {
            return
        }
        rootViewController.push(mainVC, animated: true)
    }
}

extension MainCoordinator:DelegateCaller{
    func printHello() {
        print("helloo")
    }
}

enum CoordinatoreTypes{
    case MainCoordinator
    case none
}

class Factory:UIViewControllerFactory{
    func getViewController(delegateType:CoordinatoreTypes,delegateObject:Coordinator) -> UIViewController?{
        switch delegateType{
        case .MainCoordinator:
            let controller = MainViewController()
            controller.delegate = delegateObject as? MainCoordinator
            return controller
        case .none:
            break
        }
        return nil
    }
}

class MainViewController:UIViewController{
    weak var delegate:DelegateCaller?
}

protocol DelegateCaller:AnyObject{
    func printHello()
}