A clean stable starting point for building ios apps.
Simple modular testable features/components. Stack - Factory, Coordinator, MVVM, Repository and Web service. Coordinator plugs into host app's SceneDelegate::willConnectTo with app injected navigation controller.
- DeepLinkHandler
//
// FeedFeature.swift
// archapp
//
// Created by Krishna Kumar on 1/11/23.
//
import UIKit
/// Feed Feature
/// JSON Placeholder client app
/// Interfaces
protocol FeedFeatureCoordinator {
var navigationPresenter: NavigationPresentation { get }
var delegate: FeedFeatureCoordinatorDelegate? { get set }
var navigationController: UINavigationController? { get set }
func navigateToFeed() -> ()
}
protocol FeedFeatureCoordinatorDelegate: AnyObject {}
protocol FeedWebService {
func fetchPosts(queue: DispatchQueue, completion: @escaping ([Post]?, Error?) -> ()) -> ()
}
protocol FeedRemoteRepository {
var webService: FeedWebService { get }
func fetchPosts(queue: DispatchQueue, completion: @escaping (Result<[Post], Error>) -> ()) -> ()
}
protocol PostTableViewCellDelegate: AnyObject {}
protocol FeedViewModel {
var repository: FeedRemoteRepository { get set }
var posts: [Post] { get set }
func fetchPosts(completion: @escaping (Result<[Post], Error>) -> ()) -> ()
}
/// Codables
struct Post: Decodable, Equatable {
let id: Int
let title: String
let body: String
}
/// Errors
enum WebServiceError: Error {
case invalidURL
case noData
}
enum RepositoryError: Error, Equatable {
case noData
case timeout(description: String)
case noInternetConnection(description: String)
case serialization(description: String)
}
/// Concrete, Implementation
final class DefaultFeedFeatureCoordinator: FeedFeatureCoordinator {
let navigationPresenter: NavigationPresentation
var delegate: FeedFeatureCoordinatorDelegate?
var navigationController: UINavigationController?
init(navigationPresenter: NavigationPresentation = NavigationPresenter(), delegate: FeedFeatureCoordinatorDelegate? = nil, navigationController: UINavigationController?) {
self.navigationPresenter = navigationPresenter
self.delegate = delegate
self.navigationController = navigationController
}
func navigateToFeed() {
let feedViewController = DefaultFeedFeatureFactory().makeFeedViewController()
navigationPresenter.pushViewController(feedViewController, from: navigationController)
}
}
/// Factory
class DefaultFeedFeatureFactory {
public func makeFeedViewController() -> FeedViewController {
let viewModel = makeViewModel()
return FeedViewController(viewModel: viewModel)
}
func makeWebService() -> FeedWebService {
return DefaultFeedWebService()
}
func makeRemoteRepository() -> FeedRemoteRepository {
return DefaultFeedRemoteRepository(webService: makeWebService())
}
func makeViewModel() -> FeedViewModel {
return DefaultFeedViewModel(repository: makeRemoteRepository())
}
}
class DefaultFeedWebService: FeedWebService {
func fetchPosts(queue: DispatchQueue, completion: @escaping ([Post]?, Error?) -> ()) {
let endpoint = "https://jsonplaceholder.typicode.com/posts"
guard let url = URL(string: endpoint) else {
completion(nil, WebServiceError.invalidURL)
return
}
var posts: [Post]?
var feedError: Error?
let dispatchGroup = DispatchGroup()
dispatchGroup.enter()
let task = URLSession.shared.dataTask(with: url) { data, _, error in
if let error = error {
completion(nil, error)
return
}
guard let data = data else {
completion(nil, WebServiceError.noData)
return
}
do {
posts = try JSONDecoder().decode([Post].self, from: data)
} catch {
feedError = error
}
dispatchGroup.leave()
}
task.resume()
dispatchGroup.notify(queue: .main) {
if let posts = posts {
completion(posts, nil)
} else {
completion(nil, feedError)
}
}
}
}
class DefaultFeedRemoteRepository: FeedRemoteRepository {
let webService: FeedWebService
init(webService: FeedWebService) {
self.webService = webService
}
func fetchPosts(queue: DispatchQueue, completion: @escaping (Result<[Post], Error>) -> ()) {
webService.fetchPosts(queue: .main) { posts, error in
if let error = error {
completion(.failure(error))
return
}
guard let posts = posts else {
completion(.failure(RepositoryError.noData))
return
}
completion(.success(posts))
}
}
}
class DefaultFeedViewModel: FeedViewModel {
var repository: FeedRemoteRepository
var posts: [Post] = []
init(repository: FeedRemoteRepository) {
self.repository = repository
}
func fetchPosts(completion: @escaping (Result<[Post], Error>) -> ()) {
repository.fetchPosts(queue: .main) { result in
switch result {
case .success(let posts):
self.posts = posts
completion(.success(posts))
case .failure(let error):
completion(.failure(error))
}
}
}
}
class FeedViewController: UIViewController {
let viewModel: FeedViewModel
let tableView = UITableView()
init(viewModel: FeedViewModel) {
self.viewModel = viewModel
super.init(nibName: nil, bundle: nil)
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .red
// setup and add tableView
tableView.register(PostTableViewCell.self, forCellReuseIdentifier: "cell")
tableView.dataSource = self
tableView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(tableView)
// tableView constraints
NSLayoutConstraint.activate([
tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
tableView.topAnchor.constraint(equalTo: view.topAnchor),
tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
])
// fetch posts
viewModel.fetchPosts { result in
switch result {
case .success:
self.tableView.reloadData()
case .failure(let error):
print(error)
}
}
}
@available(*, unavailable)
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
// MARK: - UITableViewDataSource
extension FeedViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return viewModel.posts.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! PostTableViewCell
let post = viewModel.posts[indexPath.row]
cell.populate(with: post)
return cell
}
}
class PostTableViewCell: UITableViewCell {
let titleLabel = UILabel()
let bodyLabel = UILabel()
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
titleLabel.translatesAutoresizingMaskIntoConstraints = false
bodyLabel.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(titleLabel)
contentView.addSubview(bodyLabel)
// Title label constraints
NSLayoutConstraint.activate([
titleLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 16),
titleLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -16),
titleLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 8)
])
// Body label constraints
NSLayoutConstraint.activate([
bodyLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 16),
bodyLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -16),
bodyLabel.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 8),
bodyLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -8)
])
}
@available(*, unavailable)
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func populate(with post: Post) {
titleLabel.text = post.title
bodyLabel.text = post.body
}
}
//DeepLinkHandler.swift
class DeepLinkHandler {
func handleDeepLink(_ url: URL) {
switch url.path {
case "/profile":
ProfileViewModel().handleDeepLink()
case "/settings":
SettingsViewModel().handleDeepLink()
default:
break
}
}
}
//AppDelegate.swift
func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
DeepLinkHandler().handleDeepLink(url)
return true
}