Frequently used design patterns in Swift

Objective-C was the primary programming language used for creating the iOS applications for a long time.Learning the Objective-C is not an easy task, its programming language is very tough and developers have to write the lengthy codes for a specific task. Here comes the Swift programming language that uses modern programming language theory concept and tries to present a simpler syntax.

Development of Swift started in July 2010, by Chris Lattner, with the help of other programmers. On June 2, 2014, in Apple Worldwide Developers Conference (WWDC), the Swift programming language was introduced.

Swift is the fairly new programming language, and many developers don’t know which design patterns they should use and how to implement. We are going to elaborate the design patterns most widely used in Swift for iOS app development.

What is the design pattern and why you should know them?

The software design pattern is a solution to a particular problem that you might face at time of designing the apps architecture. The design pattern is a template that tells you how to write code, but it's up to you to design your code according to the template. The design patterns offer few advantages that can be described below:

Common Vocabulary

You don’t need to provide in-depth explanations of how to solve software development problems. You simply tell what design pattern you have used then other developers will immediately understand the solutions you implemented.

Tested Solutions

You don’t need to waste your time in finding the problem, the design patterns already provide you with the best solution and tell you how to implement it.

Code Unification

The design patterns are helpful in providing the solutions related to testing of bug removal and also identify the mistakes during the coding and designing the app architecture.

Types of software design patterns

The design patterns used in the Swift iOS app development can be divided into three major categories such as:

• Creational

• Structural

• Behavioral

Creational

It is very helpful in creating the object mechanisms. It gives you the proper suggestion in favor of objects so that it becomes suitable for a specific condition. There are various creational design patterns:

• Factory Method

• Abstract Method

• Builder

• Singleton

• Prototype

Structural

It simplifies the process of designing by finding the easiest way for correlating the classes and objects. There are various structural design patterns:

• Adapter

• Bridge

• Facade

• Decorator

• Composite

• Flyweight

• Proxy

Behavioral

It uses the common communication patterns between the units. It includes:

• Chain of responsibility

• Template Method

• Command

• Iterator

• Mediator

• Memento

• Observer

• Strategy

• State

• Visitor

Most of the design patterns are rarely used that’s why we have picked the most frequently used design patterns in Swift to develop the apps for iOS.

MVC

Mobile-View-Controller (MVC) is an essential part of the design pattern for iOS development. It is divided into three parts.

• Model is responsible for the domain data and the data access layer which manipulates the data.

• View is responsible for the presentation layer (GUI), for iOS environment.

• Controller is the mediator between the Model and the View. It is responsible for altering the Model by reacting to the user’s actions on the View and updating the View with changes from the Model.

MVP

Mobile-View-Presenter (MVP) is the derivation model of the MVC pattern, in this controller is replaced by the presenter.

In the MVP design pattern, the presenter manipulates the Model and also updates the View. In this pattern, the View and Presenter are completely separated from each other and communicate with each other through an interface.

MVVM

Model View View-Model (MVVM) pattern supports two-way data binding between View and View-Model.

There is a special layer between View and Model called the View Model. The View Model provides the set of interfaces which represent the UI component in the View. We use the technique “binding” to connect the UI components of the View Model.

VIPER

The word VIPER is the combination of initial letters of View, Interactor, Presenter, Entity, and Routing.

The main parts of VIPER are:

• View displays what it is told by the Presenter.

• Interactor contains the business logic.

• Presenter contains the view logic for preparing the content to display.

• Entity contains the basic model objects used by Interactor.

• Routing contains navigation logic for describing which screens are shown in which order.

Builder

If you want to develop the complex object from the simple object step by step, then go with the Builder method. It allows you to use the same code for creating different objects.

If you want to design the object and divide into several steps, then you don’t need to go through all steps. You have to check only those steps that are necessary for developing an object with a particular configuration.

You need the Builder design pattern if:

• You want to avoid using a “telescopic” constructor.

• Your code needs to create different views of a particular object.

• You need to compose complex objects.

Adapter

It is a structural pattern that helps objects with incompatible interfaces to work together. It transforms the interface of the object to adapt it to the different object.

You can use the Adapter pattern to implement the third-party classes and to implement the various existing subclasses with a specific functionality.

You need the Adapter design pattern if:

• You want to use the third-party class but its interface doesn’t match the rest of your application's code.

• You want to use several existing subclasses because you cannot extend the superclass.

Decorator

It is used to add the new functionalities to an object, it is also known as Wrapper Design pattern. It allows you to add the behavior and responsibility to the object without changing the codes.

You need two types of decorators Encryption Decorator for encrypting and decrypting data and Encoding Decorator for encoding and decoding.

You need the Decorator design pattern if:

• You want to add responsibilities to the object dynamically.

• It is impossible to extend the responsibilities of an object through inheritance.

Facade

It offers an easy interface to libraries, frameworks, and the complicated group of classes. You don’t need to show the different methods with various interfaces.

It helps you in creating your own class and integrating other objects in it by offering the simpler version of the interface.

You need the Facade design pattern if:

• You want to provide a simple interface for a complex subsystem.

• You want to decompose a subsystem into separate layers.

Template Method

It is the behavioral pattern that helps you to design the algorithm and provides the response to the subsystem phases. It allows subclasses to redefine the algorithm without changing its overall structure.

You need the Template Method design pattern if:

• Subclasses need to extend the basic algorithm without modifying its structure.

• You have several classes responsible for quite similar actions.

These are the most frequently used design patterns in Swift. There are many other designing patterns that you can use according to your requirement.

Choosing the appropriate design patternis quite crucial as it allows you to develop more responsive and functional app. The ability to choose the appropriate designing pattern comes with experience, the more you involve in the development process then more you get the idea about it. At Fifium, as the leading app developing company we take care of all your development needs. We utilize the designing patterns as they not only simplify software development but also optimize the whole process and ensure high code quality and give you the best app. If you are looking for the iOS app development agency in the UK, then contact us now.