This guide encompasses best practices and recommended architecture for building robust, high-quality apps
This sample demonstrates how one can
- Setup base architecture of IOS Swift app using Clean Architecture
- Use dependency injection for layers separation
- Make api calls using Alamofire plugin.
├── Common
├── Data
| ├── Config
| ├── Datasources
| ├── Gateway
| └── Repositories
├── DI (dependency injection)
├── Domain
| ├── Entities
| └── Usecases
└── Presentation
├── Scenes
└── Routers
- Alamofire : Alamofire is an HTTP networking library written in Swift
- Kingfisher : Kingfisher is a powerful, pure-Swift library for downloading and caching images from the web. It provides you a chance to use a pure-Swift way to work with remote images in your next app.
- Resolver : An ultralight Dependency Injection / Service Locator framework for Swift 5.x on iOS
There are 3 main modules to help separate the code. They are Data, Domain, and Presentaion.
-
Data contains Local Storage, APIs, Data objects (Request/Response object, DB objects), and the repository implementation.
-
Domain contains UseCases, Domain Objects/Models, and Repository Interfaces
-
Presentaion contains UI, ViewModel, ViewController etc. Can be split into separate modules itself if needed. For example, we could have a module called Device handling things like camera, location, etc.
Entities are implemented as Swift struct
struct Hits: Decodable {
var id: Int?
var pageURL: String?
var type: String?
var tags: String?
var previewURL: String?
var previewWidth: Int?
var previewHeight: Int?
var webformatURL: String?
var webformatWidth: Int?
var webformatHeight: Int?
var largeImageURL: String?
var imageWidth: Int?
var imageHeight: Int?
var imageSize: Int?
var views: Int?
var downloads: Int?
var collections: Int?
var likes: Int
var comments: Int
var userId: Int?
var user: String?
var userImageURL: String?
}UseCases are protocols
protocol PhotoUseCase {
func getPhoto(pageSize: Int, completion: @escaping (Result<PhotoResult, Error>) -> Void)
}
Domain layer doesn't depend on UIKit or any 3rd party framework.
DataSource implement RestApi
enum PhotoDataSourceImpl: RestApi {
case getPhotoDataSource(pageSize: Int)
var path: String {
switch self {
case .getPhotoDataSource(let pageSize):
return "?key=\(Config.current.apiKey)&page=\(pageSize)&per_page=200"
}
}
var method: HTTPMethod {
switch self {
case .getPhotoDataSource:
return .get
}
}
}
Repositories implement PhotoUseCase
struct PhotoResult: Decodable {
var hits: [Hits]?
var total: Int?
var totalHits: Int?
}
struct PhotoRepository: PhotoUseCase {
func getPhoto(pageSize: Int, completion: @escaping (Result<PhotoResult, Error>) -> Void) {
return PhotoDataSourceImpl
.getPhotoDataSource(pageSize: pageSize)
.request(returnType: PhotoResult.self){ result in
switch result {
case .success(let photoResult):
completion(.success(photoResult));
case .failure(let error):
completion(.failure(error));
}
}
}
}
Presentation is implemented with the MVVM pattern
ViewModel
class PhotoViewModel {
@Injected var photoUseCase: PhotoUseCase
var photoResult: PhotoResult?
func getPhotoVM(pageSize: Int, completion: @escaping (Result<PhotoResult, Error>) -> Void) {
photoUseCase.getPhoto(pageSize: 1){ result in
switch result {
case .success(let photoResult):
self.photoResult = photoResult
completion(.success(photoResult))
break
case .failure(let error):
completion(.failure(error))
break
}
};
}
}
ViewController
class PhotoListViewController: UIViewController {
var apiResult = PhotoResult()
@IBOutlet weak var tableViewPhoto: UITableView!
var viewModel = PhotoViewModel()
override func viewDidLoad() {
super.viewDidLoad()
title = NSLocalizedString("Photo", comment: "")
viewModel.getPhotoVM(pageSize: 1) { result in
switch result {
case .success:
self.tableViewPhoto.reloadData()
case .failure(let error):
print("Failed to fetch users: \(error)")
}
}
configUI()
}
private func configUI() {
tableViewPhoto.register(UINib(nibName: "PhotoCell",
bundle: nil),
forCellReuseIdentifier: "PhotoCell")
tableViewPhoto.dataSource = self
tableViewPhoto.delegate = self
}
}
