iOS Programming: Detailed Tutorial on Clean Architecture for Developers

iOS Programming: Detailed Tutorial on Clean Architecture for Developers

In the realm of iOS app development, the ultimate goal of every coder is to create an impeccably structured code that is both readable and easy to modify in the future. However, with countless lines of code, ensuring optimal readability and understandability proves challenging.

To tackle this issue, developers are increasingly embracing clean architecture principles. By adopting these principles, developers divide the entire codebase into distinct layers, each dedicated to a specific concern or use.

As a seasoned iOS app development company, we have extensive experience in implementing clean architecture for various projects. In this blog post, we'll guide you through the essentials of clean architecture in iOS app development.

The Perks of Clean Architecture in iOS App Development

Developers are conscious of the importance of software architectures. Here are some compelling reasons to utilize clean architecture in your iOS projects:

1. A systematic architecture prevents a program from becoming a chaotic jumble of codes and commands, making it challenging to navigate.
2. By incorporating clean architecture philosophies into your project, you can streamline your code repository with manageable dependencies.
3. With nearly 2 million apps on the App Store (as of Apple's latest report), a clean architecture is what sets your app apart from the competition.
4. Your app will stand out in terms of manageability and upgradability.
5. Adding new features becomes a breeze when the source code is easy to understand.

Sean G. Wright, Lead Product Evangelist at Kentico, shared his thoughts on the subject: "I've used Clean Architecture in a couple of apps, and it's proven to be a valuable pattern for developing scalable, consistent, and composable architectures. I've also built many apps that didn't need the complexity of Clean Architecture, and I don't feel it was wrong not to use it there."

Clean architecture is more than just easy-to-read codes. It offers various noteworthy advantages, which we'll explore in the following sections.

Key Features of a Clean iOS App Architecture

Though numerous software architecture principles exist, Robert C. Martin's clean architecture philosophy stands out for several reasons. Codes written in clean architecture are modular, reusable, scalable, readable, and collaborative. Let's delve into each feature.

1. Modular - iOS apps designed using clean architecture principles have modular components. The entire app is divided into four key layers: the domain layer, the application layer, the infrastructure layer, and the presentation layer. This modular separation of layers enables developers to make changes in one layer with minimal impact on the others.
2. Reusable - Implementing clean architecture principles allows for code reuse across different parts of the iOS application. Since the codebase is separated by concerns, it's easy to create independent components of code that can be used again and again.
3. Scalable - A clean iOS architecture breaks the app into different layers, promoting clean coding. This way, developers can easily add new features and functionalities to the code without disrupting other layers of the program.
4. Readable - One of the most critical characteristics of a clean architecture in iOS is easy code readability. This architectural pattern offers a comprehensive view, with different components of the code stored in predefined folders, eliminating code clutter and promoting ease of understanding.
5. Collaborative - Clean architecture provides iOS developers with a collaborative environment to work in. With a clear separation of concerns, the front-end and back-end teams can work concurrently. Moreover, multiple developers can work on the same codebase effortlessly due to a concise and intuitive code pattern.

By implementing clean architecture principles in iOS app development, developers can enjoy these benefits. Now, let's examine the layers of clean architectural patterns.

The core principle of these layers is the dependency rule, also known as the Dependency Inversion Principle (DIP). This rule states, "All source code dependencies should point inwards." In a clean iOS architecture, the dependency inversion principle adds flexibility and scalability to the application. Since all the dependencies flow from high-level classes to low-level classes, it becomes easier to change the application's components later on.

These were the four layers and the dependency flow in a clean architecture in iOS. Now, let's explore the principles of clean architecture to better understand the role of each layer.

Five Core Principles of Clean iOS Architecture

What sets clean architecture apart from a cluttered one? Our software architecture team at Space-O Technologies believes clean architecture has specific qualities that mark it as superior. Here's an overview of those qualities.

1. Independent of Frameworks - A clean architecture does not rely on external frameworks, libraries, or tools to function. Instead, the iOS application remains agnostic of implementation details and external dependencies. This way, the framework is utilized as a mere tool instead of a vital organ.
2. Independent of UI - In a clean iOS architecture, the user interface of the application changes seamlessly without affecting other layers. You could swap your iOS application's UI with a web UI without modifying the core business logic, thus promoting modularity.
3. Independent of Database - The business rules of a clean architecture are not bound to database implementation. This means separating business logic from the database, allowing developers to move the local database to any other technology at any time.
4. Independent of External Factors - The business rules of a clean architecture are insulated from external agencies. All the dependencies are managed and implemented independently. This way, a change in business logic does not necessitate changing external dependencies from third-party services.
5. Seamless Testability - The iOS developers can test the business logic, use cases, and external dependencies individually. No two layers are intertwined, so the testing team can test the app at multiple levels (unit test, integration test, and acceptance test).

These are the fundamentals of creating an iOS app with a clean architecture. Now, let's look at some of the most popular clean architecture patterns for iOS development.

Top Three Clean Architecture Patterns for iOS Development

Choose the right clean architecture pattern to build a powerful iOS application. Here, we've discussed three of the most popular clean architecture patterns for iOS: VIPER, MVVM, and Clean Swift (VIP).

VIPER

VIPER (View, Interactor, Presenter, Entity, and Router) is one of the most common iOS development architectures. This architecture pattern helps developers write clean and concise codes that are divided into distinct components based on their roles.2. ### MVVM

MVVM stands for Model-View-ViewModel, and it's another popular architecture pattern. The MVVM pattern entirely separates the user interface from the application logic. This pattern remedies the shortcomings of other popular patterns like MVP and MVC.3. ### Clean Swift (VIP)

Clean Swift, also known as VIP (View, Interactor, Presenter), offers ready-to-use Xcode templates for coding your iOS application. These templates are well-organized and easy to modify in the future.

By using one of these patterns, developers can create a well-structured iOS app with clean, organized, and easy-to-maintain code. Now, let's delve into some examples of apps developed using clean architecture patterns.

Examples of Apps in Clean Architecture Patterns

1. View: The View component in the weather forecast app houses the codes for displaying weather information. This component takes user inputs as commands. Example: WeatherViewController.swift
2. Interactor: Here, the interactor is responsible for fetching the weather data from the server and processing it for the application. Example: WeatherInteractor.swift
3. Presenter: The Presenter acts as an intermediary between the View Controller and Interactor. It processes user inputs using the Interactor and formats the results for the View. Example: WeatherPresenter.swift
4. Entities: This is the data model of the iOS application. In the context of a weather app, Entities refer to the weather data fetched from the server. Example: WeatherData.swift
5. Router: The Router decides which screen the user should go to next based on user actions and output. Example: WeatherRouter.swift
6. Model: The Model layer in a to-do list app contains a data structure that represents to-do items. Example: TodoItem.swift
7. View: This component in our to-do list app displays a list of to-do items to the user and takes their input. This input can include check-marking an item and adding/editing/removing an item. Example: TodoListViewController.swift
8. ViewModel: In a to-do app, the ViewModel component fetches the list of to-do items from the Model component and displays them in the View component. Example: TodoListViewModel.swift
9. View Controller: This component is responsible for displaying a list of notes to the user and capture their inputs. These inputs can include adding/removing notes and formatting text. Example: NotesViewController.swift
10. Interactor: The Interactor fetches and processes notes from the central repository. Example: NotesInteractor.swift
11. Presenter: The Presenter takes the inputs from the View Controller (edit, create, delete notes) and processes them using the Interactor. It then sends the results back to the View Controller. Example: NotesPresenter.swiff
12. Model: The Model/Entity is the data model of the application. In a note-taking app, this model is the note that the user adds to the application. Example: Note.swift
13. Router: The router helps the user navigate from one screen of the note-taking app to the other. The user can switch screens based on their commands and outputs. Example: NotesRouter.swift

Note-taking App in Clean Swift

To-do List App in MVVM

Weather App in VIPER

By using a clean architecture pattern, developers can create an iOS app with clean, modular, and easily maintainable code. Selection of the right pattern depends on your app's requirements and preferences. Still, have questions? Check our FAQs for additional information.

Resources

1. Clean Architecture in Action: Designing Modern Multi-Layer Applicationshttps://mjfi.it/clean-architecture
2. Implementing Clean Architecture in iOS: How and Whyhttps://realm.io/news/implementing-clean-architecture-ios/
3. Clean Architecture with Swift: Create Clean and Easy-to-Understand Code in iOShttps://www.raywenderlich.com/books/clean-swift-for-swiftui/chapters/5-your-first-app-search-app
4. Clean Swift Architecture: A Comprehensive Guidehttps://titandevelopment.com/blog/cleanSwiftArchitecture/

Need Expert Assistance?

Are you still unsure about clean architecture and its applications? Do you need help implementing clean architecture principles in your iOS development project? Reach out to us today.

Space-O Technologies boasts an elite software architecture team with a proven track record of implementing clean architecture strategies. We're ready to elevate your project's efficiency and quality through clean architecture implementation.

1. Due to their modular and scalable nature, clean architecture principles, applied in the context of iOS app development, offer a conducive workspace for multiple developers to work synchronously on the same codebase.
2. By adopting clean architectural patterns, developers can ensure that their codes are not only easily readable and manageable but also stand out from the competition on the App Store due to their streamlined code repositories and manageable dependencies.

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