The Important Swift Design Patterns for iOS App Development

Swift, a multi-paradigm programming language developed by Apple, was released back in 2014. Since then, it has gained ground in the developer’s community for developing feature-rich apps for iOS, macOS, and tvOS. In a recent study, Redmonk has assigned Swift a higher ranking in its list of top 20 programming languages for making the developer’s job easier while adding dynamism to customized apps.  

The iOS app development company has an in-house team of skilled iOS app developers who are familiar with different design patterns for creating appealing and seamlessly-performing apps. These patterns have a direct relationship with the functionality and security of iOS apps. They are template-based solutions designed to address the common concerns of software design.

Key advantages of design patterns include code unification, reusing vocabulary or code, and develop optimum app solutions. Let’s move to Swift design patterns  

Categories of Swift Design Patterns

We can broadly classify the design patterns of the Swift iOS app development in three categories. These include

  1. Creational
  2. Structural
  3. Behavioral

Let’s elaborate on them one after another. 

1. Creational

These patterns are particularly helpful in developing object mechanisms. Creational patterns offer concrete evidence in the object’s favor to make the object suitable for a specific condition. This type includes various methods like Singleton, Abstract, Builder, Factory, etc. Let’s discuss them in brief-

Singleton Method

This method is applied when developers need to use only one instance for a single object or a given class. As the name suggests, the single instance receives global access. Initially, this method makes use of a lazy loading process and develops a single instance. 

Apple uses this common approach. For example, UserDefaults.standard, UIScreen.main, FileManager.default, etc. return a Singleton object. Here are the codes for the EventManager object.

private override init() {}
  static let sharedInstance = EventManager()
  override func copy() -> Any {
   fatalError("You are not allowed to use copy method on singleton!")
override func mutableCopy() -> Any {
   fatalError("You are not allowed to use copy method on singleton!")

Abstract Method

This method is the same as the Factory Method. The difference lies in using this method to develop a group of objects. This pattern restricts you to predict the implementation. However, it helps developers select a particular object.

//heart of pattern
   final class func getFactory(car: Cars) -> CarFactory? {
     var factory: CarFactory?
     switch car {
     case .compact: factory = CompactCarFactory()
     case .sports: factory = SportsCarFactory()
     case .SUV: factory = SUVCarFactory()
     return factory

This method remains at the abstract base and can be used to build the structure of the car.

Builder Method

This method is useful for developing complex objects from simple objects systematically.  Its real advantage is developers need to use a similar code for developing different objects. This method segregates the object from its list. Here, the task is given to specific objects called builders and they are separated into several steps. 

This method is useful for developing a restaurant iOS app, in which the iOS app development company can integrate the order functionality using Builder Method. 

2. Structural

The Structural Design pattern enables the developers to simplify the designing process and shows an easy method for correlating the objects. It consists of other methods like MVC, Adapter, Facade, and Bridge.



Model-View-Controller aka MVC is well-known as an essential design pattern for developing iOS apps. Here, the Model is implied with the data only. The View can be associated with all aspects including the UI and animations. The Controller collects and controls everything. It is known for its complexity. MVVM or Model-View-View-Model is an advanced pattern. 


Another popular structural pattern is the Adapter. It helps objects work simultaneously though their interfaces are mismatched. The adapter encapsulates the object and converts its data into feet. 

This pattern works wonders when it comes to implementing the third-party classes in which the interface is mismatched, and there is no connection with the rest of the code. It can be used when there is a need to employ different existing subclasses that are not complying with specific functionality. 

The best example of the Adapter method is The Calendar and the Event Management apps for iOS devices. Here, developers incorporate the Eventkit framework and adapt the Event model from the framework to integrate the calendar. 


It is a useful pattern that offers an easy interface to libraries, frameworks, or any complicated groups of classes. Here developers can get rid of showing a number of methods with various interfaces. 

This pattern assists developers to create their own class and wrapping the other objects in the class. The facade also helps developers decompose subsystems into different layers. It is typically useful for implementing audio recording and playback functionality into an iOS app. 

3. Behavioral

Behavioral patterns are useful for developing and integrating common communication patterns between the units. These patterns have other methods like Template Method, Observer, Momento, etc.

Here is a brief discussion of these methods. 

Template Method

It is the backbone of the algorithm. It helps the iOS app development company to redefine the phases of an algorithm without modifying the overall structure. The algorithm is divided into many substeps and each substep is described in different methods thanks to the Template method. 

For example, while building software for taking and saving pictures in iOS devices, you need the permission of both device camera and photo gallery. Here, developers can implement the PermissionService base class with a particular algorithm.  


In this pattern, the object notifies the other objects about the change in the state. Here, one object signs the changes of the other one. Push Notifications is an excellent example of the Observer pattern. 


It helps in saving objects like UserDefaults and NSCoding protocol using the CoreData.  


This is another important behavioral pattern. In this pattern, a method is linked up with an action touch to get a user interface. 

Concluding Remarks

Here we have included some of the noteworthy design patterns of Swift for iOS app development, The mobile app development company uses the right design pattern for your iOS app by considering various project requirements. 

When it comes to developing a more responsive and excellently performing app with enhanced security, the design pattern plays a crucial role. It can make app development and maintenance processes simpler while offering app developers a new scope.

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Author Info

Robert Jackson is a content cum digital marketer at Solution Analyst, a leading mobile app development company. He is an avid reader and likes to remain updated for technological advancements in the domains of web, mobility, IoT, and emerging technologies. His articles are informative and interesting at the same time as he expresses insightful thoughts clearly.