iOS swift : extract a common method using type as input params?

Question

我有3个结构非常相似的方法，我想提取一个通用方法，如下所示:

private func navigateToViewController(animated: Bool, viewControllerType: T, viewControllerNibName: String, mode: MenuMode) { ... }

但是，我不知道如何处理类型参数，有什么好的建议吗？谢谢!

private func navigateToEditorView(animated: Bool) {
    self.dismiss(animated: false, completion: nil)

    if self.editorViewController == nil {
        let editor = EditorViewController(nibName:"EditorViewController", bundle: nil)
        editor.exitCallBack = self.setBackgroundImage
        self.editorViewController = editor
    }

    if let editor = self.editorViewController {
        self.navigationController?.pushViewController(editor, animated: animated)
    }

    self.currentMenuMode = .editor
}

private func navigateToStorageView(animated: Bool) {
    self.dismiss(animated: false, completion: nil)

    if self.storageViewController == nil {
        let storage = StorageViewController(nibName:"StorageViewController", bundle: nil)
        storage.exitCallBack = self.setBackgroundImage
        self.storageViewController = storage
    }

    if let storage = self.storageViewController {
        self.navigationController?.pushViewController(storage, animated: animated)
    }

    self.currentMenuMode = .storage
}

private func navigateToGalleryView(animated: Bool) {
    self.dismiss(animated: false, completion: nil)

    if self.galleryViewController == nil {
        let gallery = GalleryViewController(nibName:"GalleryViewController", bundle: nil)
        gallery.exitCallBack = self.setBackgroundImage
        self.galleryViewController = gallery
    }

    if let gallery = self.galleryViewController {
        self.navigationController?.pushViewController(gallery, animated: animated)
    }

    self.currentMenuMode = .gallery
}

Answer 1

我认为使用协议(protocol)是处理您所有问题的最佳方式

enum MenuMode {
    case editor
    case storage
    case gallery
}

protocol ExitCallBackHandler where Self: UIViewController {
    var exitCallBack: (() -> Void)? { get set }; // I don't know what it is
    var currentMenuMode: MenuMode { get }
}

各个ViewController的接口(interface)

class EditorViewController: UIViewController, ExitCallBackHandler {
    var exitCallBack: (() -> Void)?
    var currentMenuMode: MenuMode {
        return .editor
    }
    // ...
}

class StorageViewController: UIViewController, ExitCallBackHandler {
    var exitCallBack: (() -> Void)?
    var currentMenuMode: MenuMode {
        return .storage
    }
    // ...
}

class GalleryViewController: UIViewController, ExitCallBackHandler {
    var currentMenuMode: MenuMode {
        return .gallery
    }
    var exitCallBack: (() -> Void)?
    // ...
}

最后

private func navigateToViewController<T: ExitCallBackHandler>(animated: Bool, viewControllerType: T.Type) {
    self.dismiss(animated: false, completion: nil)
    var vc = T(nibName: String(describing: viewControllerType), bundle: nil)
    vc.exitCallBack = ...
    self.currentMenuMode = vc.currentMenuMode
    self.navigationController?.pushViewController(vc, animated: animated)
}

这样使用:

navigateToViewController(animated: true, viewControllerType: StorageViewController.self)