10 Best iOS Design Patterns to Develop Powerful iPhone Apps

iOS design patterns form a very important part of the iPhone and iPad development process. They are reusable solutions that answer common problems in any software design. Being template-based, these design patterns help write codes that are extremely easy to use and reapply. Moreover, they help in creating loosely coupled codes making it easier for developers to change or replace the elements in the code with minimal effort.

In this article today we are going to talk about the different design patterns that an iOS app development company uses.

Let us get right into it.

1. Builder

The iOS design pattern is used for dividing configurations and objects. The pattern is known to manage different aspects of iOS app development ranging from data groupings, object creation, and instructions. These elements lead to the creation of objects which are straightforward, clear, and extremely easy to test.

Use Builder when:

• When the code has to be written for creating multiple views of one object

• When you have to avoid telescopic constructors

• When there is a need for composing complex objects.

2. Facade

The iOS UI design pattern helps with offering a simple interface for making sophisticated programs. It builds classes that offer simplified interfaces irrespective of multiple methodologies with individual interfaces.

When a developer is looking to decompose the subsystems in distinct levels like database, file systems, remote servers, and memory, the pattern comes in very handy.

Use Facade when:

• When you have to create a unique and simple interface to a complicated subsystem

• When you have to break the subsystem in multiple layers.

3. MVC

It is one of the most used Swift architecture patterns in the market today. It classifies the objects in an iOS application depending on their specific needs, enabling code separation by the role, which falls into - Model, View, and Controller.

Model stores and explains how to manipulate the app data. The view is needed for the visual representation of the model. The controller analyses the model’s data and then uses a view to manipulate it as and when needed.

Use MVC when:

• When you have to maintain the data flow structure

• When you are looking for smooth collaboration between the clients and the team

• When you have to keep the code from becoming messy

4. Singleton

The Swift pattern is everything about building one instance of a class having global access. Following this, when the single instance is needed for the first time, lazy loading gets used. They come in handy when having only one instance makes sense for the class.

Use Singleton when:

• When the program’s class must only have one instance for every client

• When a more robust control is needed over the global variable

5. Adapter

The Swift structural design pattern makes it possible for the objects having incompatible interfaces to operate together. It helps developers enclose the object which deals with the meters and then convert the information to feet. Because of this, the Adapter can be used for implementing the third-party classes when the interface is out of sync with the other application code. The developers can also use it when they need a variety of the existing subclasses which don’t have similar capabilities.

Use Adapter when:

• When you require a third-party class and the interface does not match the code

• When you have to employ multiple subclasses but they have any specific function

6. Decorator

The Swift design pattern helps in adding multiple functionalities to an object and then wrapping them in the wrappers. It enables the developers to add responsibility and behavior to the object without altering the code. The pattern also comes in handy when the developers use third-party libraries as you don’t have to read the source code.

An example of this can be seen in EncodingDecorator and EncryptionDecorator.

Use Decorator when:

• When you have to add functionalities in the object but want it to not highlight in the code

• When you have to add in new functionalities through inheritance

7. Template method

It is a behavioral Swift design pattern that explains the algorithm’s skeleton and then assigns responsibility for specific subclasses and phases. The pattern enables the developers to rewrite some phases of the algorithm without impacting the general structure of the method.

The pattern is known for breaking down an algorithm into multiple steps, differentiating them in methods, and then calling them through a single template method.

Use template method when:

• When you have multiple classes that are responsible for similar actions

• When you have to extend an algorithm without modifying the structure

8. MVVM

It is a Swift design pattern that is used by a majority of iOS app developers. It comes with visual elements like UI components, animations, and layout, all in the MVVM architecture. Moreover, the ViewModel layer that lies between Model and View is designed to express the view canonically. Generally, the mobile app development company uses the pattern for its set of interfaces which represents the UI elements in the view.

9. Observer

It is a design pattern that is known for defining one-to-multiple relationships between objects. It means, that whenever one object’s state changes, the dependents are directly changed and notified.

Here, the observers and subjects are related in the observer designer pattern where the communication happens between the observer and the observed elements.

Use Observer when:

• When you have multiple objects that rely on other objects

• When the object needs to act within the object change state

• When the objects have to notify other elements

10. Factory method

When you need to decide between the protocol-based classes and use classes, a pattern is required. The classes are all determined logically in the pattern leading to you choosing between the base class and the global methods class.

Use the Factory method when:

• When the object class is not sure of which sub-class to create

• When the object class is created the sub-class defines the object

• When the object divides its responsibility across auxiliary sub-classes

So here were the ten iOS design patterns that are generally used by iPhone and iPad app development companies when building Apple software. We hope that you must have gotten an idea of which one to use in your next iOS application.

Hey, My name is Ema William, Love to write about technologies and new tech trends.