How to Become an iOS Developer: An Essential Guide

It is an undeniable fact that the future belongs to technology and tech-savvy individuals. As more and more businesses and companies currently rely on apps, either mobile or web, the demand for app developers is increasing and will continue to grow in the years to come. A higher demand for app developers has also made the salaries go up. iOS developers are among those who get paid well. 

This article will provide you with a comprehensive guide to becoming an iOS app developer and become a lucrative part of the unending tech market. 

The Importance of an iOS developer 

The importance of an iOS developer is directly connected to the importance of the apps that are available on the App Store for businesses and companies. It is commonly believed that Apple devices are more reliable and safe to use, and iOS apps are more secure than those developed for other operating systems. 

As mentioned above, companies are relying on these apps more and more for their business activities, better ROI, and customer satisfaction. This dependency makes iOS developers important for businesses and individuals. These individuals are important because they develop apps that are user-friendly and there are lower chances of data loss or theft. This importance and shortage of iOS developers are also the reasons for them to be in demand. 

Basic Requirements to Become an iOS Developer

What do you need (as the bare minimum) to have before you can become an iOS developer? Let's go through it all from equipment to programming languages.

Equipment 

Mac Computer

The most basic equipment you need to become an iOS developer is a Macintosh computer. You need a computer system that runs on macOS because the software and systems that are used to develop iOS apps are only compatible with Mac operating systems. Although, there is a way to run macOS on other computers but you can only do that by getting a license from Apple, and that is not easy. In other words, if you do not have a licensed Mac, you cannot upload the app on the App Store. 

Software 

Xcode

The first and foremost software that you need on your computer is Xcode. It is available for free on the App Store for Mac computers. This Integrated Development Environment (IDE) provides developers with multiple tools i.e. debugger, instruments, simulator, and more, that help in app development for Apple products. Xcode is a complete and comprehensive system of developing and testing iOS apps and making sure they’re submitted and uploaded on the App Store. There are multiple available templates to build and develop apps for different devices, platforms, and app types to make the development process easy. 

Swift Playgrounds 

To become a professional app developer for Apple devices, you need to learn the most important programming language in the Apple ecosystem, Swift. Swift Playgrounds is probably the best way to learn Swift for iOS app programming. It helps to learn the language through different challenges and puzzles, without even requiring the developer to have the basic programming knowledge. You’ll use Swift when you become a professional developer by learning how to generate code with this language. You can install Swift Playgrounds from the App Store.

Programming Languages

Swift 

Swift is the best programming language to learn to develop apps for iOS and other operating systems, like iPadOS or watchOS, running on Apple devices. Apps developed with Swift only work on devices running on iOS 7 or later - 92% of iPhone devices issued in the last four years by Apple are running iOS 13. It is a multi-paradigm, object-oriented, and protocol-oriented programming language which uses the open-source LLVM compiler. 

If you do not have enough adequate experience and knowledge of programming languages then you will need to learn different object-oriented concepts and commands to become a coding expert and start programming with Swift. Swift Playgrounds plays an important role in helping you learn these commands, signs, and concepts. There are also official comprehensive guides available to learn this language on iBooks. 

Swift is an open-source language developed by Chris Latner at Apple in 2014. However, it was initially a proprietary language that Apple decided to open source on GitHub in December 2015. Since then Swift language has become part of many other development platforms as well which are not owned by Apple like Vapor and Kitura. It maintains a vibrant online community at swift.org.

Almost all of the new libraries and development by Apple is now done in Swift. 

Objective-C 

Another important programming language that you need to learn to become a professional iOS developer is Objective-C. It was a significant part of Apple’s app development and programming process before the introduction of Swift. Some people suggest against learning this language as Swift has replaced it, but you should have a basic understanding of coding and programming because it has been Apple’s primary programming language in the past. 

Both Swift and Objective-C can be used together as CLang, a front end which parses C, C++ and Objective C code, can translate all of the languages and convert them into a representation suitable for LLVM.

Objective-C was developed in the 1980s but as a language has not evolved much since then. The primary frameworks we use as part of Cocoa and Cocoa Touch for development of iOS and other platforms including FoundationKit, UIKit, AVFoundation, CoreImage have been written in C and Objective-C for years. So an understanding of Objective-C can help not only to develop apps in Objective-C but understanding of these libraries as well. 

Step-by-step guide for beginner iOS Developers to learn Swift coding 

Swift is the language of the present and future for iOS developers. It is advancing and there are the latest versions of the language being introduced after intervals. What is constant is the functionality and appropriateness of Swift for iOS development. Below is a list of what a beginner needs to learn to become an iOS developer at least at a basic level. For advanced development, the sky's the limit.

Basic syntax

Learning Swift coding begins with basic syntax as it provides comprehensive knowledge about the language. Without learning the syntax, an individual won’t be able to learn the basics of the language and write even a single piece of code. These are terms, keywords, and commands used in the codes you write.

You can learn basic syntax using the official Swift handbook, or using the tutorials provided by RayWanderlich and CocoaCasts by Bart Jacobs.

Variables and constants

The variables and constants in Swift are different from other languages. One needs to understand that there are different types of variables and constants. In Swift, the variable values are created with the keyword ‘var’, and the constant values are created with the ‘let’ keyword. The value assigned to a constant can’t be changed, otherwise there will be a syntax error in the code you create. 

Appropriate usage of let and var help Swift to effectively manage the memory. The rule of thumb is to use the ‘let’, unless you need the ‘var’. This is how you can simply create a constant and variable in Swift:

        var name = "kooper"

        let x = 1

One needs to understand Swift uses type inference to automatically understand the type of data in a variable or constant. This is a new feature that was not part of Objective-C. In some cases, a developer would need to explicitly provide by adding a colon. Like here we want to differentiate between Float and Double:

        let pi: Double = 3.14

Loops

Loops in Swift are similar to other languages. You can add a for loop to repeat a piece of code more than once. A loop repeats executing a chunk of code unless a condition is met. Here is the simplest way to create a loop that repeats 100 times:

         let list = 0..<100
         for item in list { 
            print("item is \(item)")
         }

A loop is fundamental in programming as we can use it to populate a list or keep updating the background in a game. 

Functions 

Functions in your code make the app or software perform a particular task. As a developer, first you need to define the function and then call it. Defining a function means to prepare the function and make grounds to call and perform it. You can repeat several functions. Means you can call a function many times because it is the same every time you have to call it. You don’t have to create a new code for a repetitive function and can just copy it. A function in Swift starts with the ‘func’ keyword and followed by its name and (). If the function returns some data we can mention its type after an arrow -> operator

    func pet() -> String {
        return "Kooper"
    }

Optionals 

Optionals is a great addition in Swift that is a good programming practice to help developers reduce nil/null errors that could cause sudden crashes in apps for users. This is because an optional can hold nil without a problem.

A good way is to keep all of your variables as optional variables while you declare them or pass them as a method parameter. You need to only unwrap the Optionals when you have to use the data in variables like while populating the UI or doing some business logic. With that, we can save tons of use cases and scenarios that would cause a crash and only focus when we are using them. Furthermore, Optionals can also help us to create default parameters in Swift methods.

To use Optionals, you only need to put a “?” question mark operator at the end of your data type declaration in a variable. The “?” will show that we are unsure if the variable has a value or not.

Here is an example of Optionals. A variable of String type is created for ‘currentAddress’ but with a “?” which shows this var can have a nil.

var oldAddress: String?

You can also use Optionals to create a failable initializer, which means you can also return an optional object while initializing an object. 

UITableView and UICollectionView

If you know how to make var, let, function, loop and if-else and optionals. You can start making your first simple application like Notes or To-do list. Try to use UITableView or UICollectionView which can show a list of items in the view of the screen. A user can then select an item to see the detail. You can finish your first basic app and submit it to the App Store for publishing.

      func tableView(_ tableView: UITableView, numberOfRowsInSection    section: Int) -> Int {
            return self.data.count
        }

        func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
            let cell:UITableViewCell = self.tableView.dequeueReusableCell(withIdentifier: cellReuseIdentifier) as UITableViewCell!
            cell.textLabel?.text = self.data[indexPath.row]
            return cell
        }
        func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
            print("Selected: \(indexPath.row).")
        }

A link to the demo app is given at the end of this article.

New Skills for iOS Developers to learn in 2021

You need to have a good grasp of networking libraries like AlamoFire and Kingfisher, maintaining codebase in version control like Git, design patterns, and architectural patterns like MVVM. However, here are few skills you need to learn that truly belongs to Swift or Xcode:

SwiftUI skills 

Among the most important and significant skills an iOS developer should learn to become valuable is learning the SwiftUI. It provides the developers with multiple capabilities for a responsive design and appearance of the app. App developers are the ones to develop the UI of the app and place an image, graphic, text box, button, and table, etc. in an app, and learning SwiftUI makes this job easy. Having the skills and expertise of this platform to design apps, an iOS developer’s job of designing the best apps through Swift would become easier. 

SwiftUI is the latest step by Apple to help developers in creating responsive UI and binding them with the controllers. SwiftUI is a declarative UI framework like XML which is used by Android. A declarative framework focuses only on how to populate the data and not what to populate.

Before SwiftUI, developers had the option to create UI using Storyboards, Xibs, and using the code. All of these approaches are great and have their own set of pros and cons. SwiftUI brings “Bindings” which has become my new favorite feature. This was something we could only do using RxSwift in the past. 

Code and app testing 

Testing is a significant part of the whole app design and development process. Every iOS developer needs to learn how to test the codes they have written and make necessary changes to it to make sure it works perfectly. Testing requires running the main and alternative use cases again and again to remove the flaws. The developers should be able to create unit test codes to test the app or software. Without having the skills to write test codes, an iOS developer might not be able to succeed in their career.

Thankfully Apple provides the XCTest framework which can help you to do unit testing, performance testing and UI testing. The framework is part of Xcode and integrates seamlessly with the testing workflow.

You can also run Profile which will run your app on a selected simulator or device along with the instrument of your choice like Time Profiler, Core Animation, Memory Leaks, Allocations, etc.

Other than that, you can use run Analyze which will run a static analyzer that will find issues 

Core Data

An iOS developer sometimes would not want the app they have developed to lose all its data after a user closes or kills the app. Learning the Core Data skills helps the developers to make their apps able to retain all the core app and customer data in the device. This retention of data helps the users to continue using the app where they left during the previous session. This is among the primary skills an app developer needs to learn. 

Grand Central Dispatch 

An app performs a lot of functions at a time and there is a dire need to align all these functions for smooth app performance. The Grand Central Dispatch (GCD) is one best way to responsibly make all these functions work in perfect harmony and concurrency. A developer needs to have skills and knowledge to make concurrency of these functions possible to make the device run a particular app smoothly. 

Processing the commands given by users, fetching data from a vast network of information, and displaying all the information on the screen may slow down the device performance. The GCD skills of a developer make it possible for the app and device to perform these functions simultaneously without any glitches or effects on the performance.

Technically speaking, GCD allows you to dispatch a part of code on the background thread, foreground/UI thread, or on your own created thread with a set priority. For example, a developer may want to update the UI as the highest priority when a user executes the app but on the contrary, will not mind executing synchronization of profile settings as the lowest priority. 

Conclusion 

Mobile and web applications have become a fundamental part of modern-day business cultures and everyday human life. In the wake of all this, an app and software developer is an integral part of the market and society. The number of users using iPhone devices has crossed the 1 billion mark, and there is an increasing demand for expert iOS developers. The most basic and primary things an individual can do to become an iOS developer is to have a Mac computer, install Xcode in it, and learn Swift coding at the very earliest. Swift is the primary coding and programming language to develop apps for all Apple devices now, and one can’t become an iOS developer without learning Swift coding and programming. 

Here is a sample demo app built using Storyboards and MVVM. You can install it from here. For more information please join our community.