Input/Output
Input
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protocol MoviesListViewModelInput {
func viewDidLoad()
func didLoadNextPage()
func didSearch(query: String)
func didCancelSearch()
func showQueriesSuggestions()
func closeQueriesSuggestions()
func didSelectItem(at index: Int)
}
Input은 View(유저)로부터 전달받는 이벤트들을 가지고 있음
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// MARK: - INPUT. View event methods
extension DefaultMoviesListViewModel {
func viewDidLoad() { }
func didLoadNextPage() {
guard hasMorePages, loading.value == .none else { return }
load(movieQuery: .init(query: query.value),
loading: .nextPage)
}
func didSearch(query: String) {
guard !query.isEmpty else { return }
update(movieQuery: MovieQuery(query: query))
}
func didCancelSearch() {
moviesLoadTask?.cancel()
}
func showQueriesSuggestions() {
actions?.showMovieQueriesSuggestions(update(movieQuery:))
}
func closeQueriesSuggestions() {
actions?.closeMovieQueriesSuggestions()
}
func didSelectItem(at index: Int) {
actions?.showMovieDetails(pages.movies[index])
}
}
실제 구현부는 위처럼 이루어지며 view로부터 전달받은 이벤트에 대응하는것을 볼 수 있음
Output
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protocol MoviesListViewModelOutput {
var items: Observable<[MoviesListItemViewModel]> { get } /// Also we can calculate view model items on demand: https://github.com/kudoleh/iOS-Clean-Architecture-MVVM/pull/10/files
var loading: Observable<MoviesListViewModelLoading?> { get }
var query: Observable<String> { get }
var error: Observable<String> { get }
var isEmpty: Bool { get }
var screenTitle: String { get }
var emptyDataTitle: String { get }
var errorTitle: String { get }
var searchBarPlaceholder: String { get }
}
화면에 보여줄 정보들을 담고 있음
Input과 Output이 프로토콜인건 ViewModel을 testable하게 만들기 위함
Input이 모두 메서드였던 것과 다르게 Output은 모두 프로퍼티로 구성되어 있음
Action
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struct MoviesListViewModelActions {
/// Note: if you would need to edit movie inside Details screen and update this Movies List screen with updated movie then you would need this closure:
/// showMovieDetails: (Movie, @escaping (_ updated: Movie) -> Void) -> Void
let showMovieDetails: (Movie) -> Void
let showMovieQueriesSuggestions: (@escaping (_ didSelect: MovieQuery) -> Void) -> Void
let closeMovieQueriesSuggestions: () -> Void
}
Action은 그 화면에서의 action들을 관리하는 장소
Coordinator에서 viewCotroller를 만들어줄때 위 struct의 인자(클로저)를 생성하여 채워넣어줌
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final class MoviesSearchFlowCoordinator {
private weak var navigationController: UINavigationController?
private let dependencies: MoviesSearchFlowCoordinatorDependencies
private weak var moviesListVC: MoviesListViewController?
private weak var moviesQueriesSuggestionsVC: UIViewController?
init(navigationController: UINavigationController,
dependencies: MoviesSearchFlowCoordinatorDependencies) {
self.navigationController = navigationController
self.dependencies = dependencies
}
func start() {
// Note: here we keep strong reference with actions, this way this flow do not need to be strong referenced
let actions = MoviesListViewModelActions(showMovieDetails: showMovieDetails,
showMovieQueriesSuggestions: showMovieQueriesSuggestions,
closeMovieQueriesSuggestions: closeMovieQueriesSuggestions)
let vc = dependencies.makeMoviesListViewController(actions: actions)
navigationController?.pushViewController(vc, animated: false)
moviesListVC = vc
}
private func showMovieDetails(movie: Movie) {
let vc = dependencies.makeMoviesDetailsViewController(movie: movie)
navigationController?.pushViewController(vc, animated: true)
}
private func showMovieQueriesSuggestions(didSelect: @escaping (MovieQuery) -> Void) {
guard let moviesListViewController = moviesListVC, moviesQueriesSuggestionsVC == nil,
let container = moviesListViewController.suggestionsListContainer else { return }
let vc = dependencies.makeMoviesQueriesSuggestionsListViewController(didSelect: didSelect)
moviesListViewController.add(child: vc, container: container)
moviesQueriesSuggestionsVC = vc
container.isHidden = false
}
private func closeMovieQueriesSuggestions() {
moviesQueriesSuggestionsVC?.remove()
moviesQueriesSuggestionsVC = nil
moviesListVC?.suggestionsListContainer.isHidden = true
}
}
위의 코드에서는 viewController를 다루는 방식이 독특해서 (child view controller의 활용 등)
coordinator에서 해야하는 일인 화면전환을 다루는 것처럼 보이기도 하지만
그것과는 구분을 지어야 함
가령 화면에 tableView가 처음에는 표시되지 않다가
search 버튼을 눌렀을때 결과를 보여주는 tableView가 나오게 하려는 경우에
showTableView와 같은 action을 만들어서 사용하는 것
action으로 동작을 분리해야겠다는 생각이 들 때 분리해도 충분하다고 생각된다.
