Kotlin For Android Developers: The Complete Guide

Today, most mobile developers need to know Kotlin to build Android apps. But Kotlin is not a new programming language. It is not even new for Google developers: it has been around since 2011 and is officially supported in their primary development environment, called IntelliJ IDEA.

So what is the deal with Kotlin, Android, and all these developers needing to know it? The answer lies in how you look at it. If you are an experienced software engineer with a background in computer science or related fields, learning Kotlin might seem like a natural progression of your skillset.

But if you’re an average Android developer who simply understands basic Java syntax and functions as well as some third-party libraries like Retrofit and RxJava, then getting started with Kotlin can feel like jumping into the deep end of a pool.

How to Start Learning Kotlin for Android Development?

If you have decided that you want to learn Kotlin for Android development, your first step should be to familiarize yourself with the syntax of the language. The syntax is the set of rules that defines how a programming language is written and read.

It is not the same as the meaning of a language: a simple sentence in English can contain multiple syntaxes for different elements. For example, a sentence like “I used to love visiting my grandparents in Texas.” has multiple syntaxes: I, used to, love, visiting, my grandparents, in, Texas. You can use syntax highlighting in your IDE (like Android Studio) to learn the basics of how to write Kotlin code while you read through documentation and online examples.

Once you are familiar with the syntax, you can then start using it in practice by building small projects or learning with interactive exercises.

Should You Learn Kotlin?

If you are not currently working as an Android developer and are simply curious about what it’s like to build an app, then your best bet is to learn Java first. Java is the original language that Google recommends for developing applications on the Android platform, and it will remain the primary language used in Android development for the foreseeable future.

It is also more common for developers to be hired if they have a solid understanding of Java. If, on the other hand, you are an experienced Android developer who wants to be more efficient in their work, then you should definitely learn Kotlin as soon as possible.

Keeping up with technology is important for the longevity of any developer’s career. As the market for Android apps grows and more people take advantage of its reach, more and more companies will be looking for Kotlin developers to add to their team. You will be in high demand if you have the skills that they need, and you’ll also be able to work more efficiently as you learn new ways to avoid common development pitfalls.

Kotlin for Android: The Basics

Kotlin is a general-purpose programming language, meaning that it can be used to build software for all kinds of industries. It can be used to build web apps, desktop apps, on the go applications, and of course, Android apps.

Google is recommending it as the primary language for Android development, and many large companies and startups are using it to create their apps. Kotlin code is compiled into Java bytecode, which Android’s virtual machine (VM) can understand and run.

Therefore, you don’t have to do anything special to compile your Kotlin code into an APK to install it on your device. In fact, you can include Kotlin in your existing Android project and start writing some of your code in Kotlin right away without having to rewrite your entire app.

Types and Operators in Kotlin

Kotlin has a type system with strong typing (similar to Scala or Swift) that helps prevent errors at compile time. It also lets you define and use your own types, which is helpful for organizing your code and making it easier to understand for your colleagues.

If you have a list of objects in your app, for example, you can use an ArrayList in Java but a List in Kotlin, which makes it easier to understand what the list represents. Kotlin also lets you define your own operators, which can make your code more concise and readable. For example, you can define an operator to subtract temperatures, so that if you have a Celsius value and a Fahrenheit value, you can subtract one from the other with a single line of code.

Working with Objects in Kotlin

The biggest difference between Java and Kotlin is that in Kotlin you work with objects. You declare objects, create methods on them, and pass them around. Java, on the other hand, is a strongly typed language that uses primitive types like int, long, byte, and so on.

In Kotlin, you can convert a primitive type into an object using a feature called “auto-boxing.” In Java, you explicitly define how you want your data types to be used. This works well when you are developing a simple app with only a few end users, but things become more complicated when you are writing code for millions of people.

It takes more effort to maintain the app when you have to specify the data types, which brings us to the next point; performance.

3 Best Practices to Become a Confident Kotlin Developer

Kotlin developer

Experiment with syntax

There is more than one way to do things in Kotlin, so it’s a good idea to familiarize yourself with the different options so you can use the one that best suits your project and skill level.

Don’t be afraid to break things

When you are learning a new language, it is inevitable that you will make a few mistakes along the way. Instead of trying to be perfect, use your experimentation as a way to learn how things work in Kotlin.

When you make a mistake, try to understand why it happened and what you can do differently next time.

Get feedback

It is easy to get lost in the details of a project when you are learning a new language, so it is important to get feedback from your colleagues or a language community so you can keep your focus on the big picture.

Advantages of using Kotlin in Android Development

There are many advantages of using Kotlin for Android development. Let’s have a look at some of them:

Faster Development in Kotlin

Many programmers prefer Kotlin because it speeds up development. Kotlin is concise and expressive, which means you can write less code with less effort and less chance of bugs.

If a developer is more productive and efficient, he or she can create more apps in less time, which means more apps in the marketplace.

Kotlin also has a very intuitive syntax i.e. grammar and structure that lets you avoid common pitfalls new programmers often make. This greatly reduces the debugging time, which means you can experiment more freely without worrying about breaking the code.

Null Safety in Kotlin

As an Android developer, you know the dreaded NullPointerException is a constant threat. The problem with Java is it doesn’t have any built-in safeguards against using null references. This is one of the major advantages of Kotlin.

Kotlin is a “strict nullability” language. This means every reference has an explicit type, and it is either null or non-null. So, if you try to use a reference that is null, the compiler will give you an error. This feature alone can prevent countless bugs and frustrations when creating Android apps.

Type Inference in Kotlin

This means the compiler can deduce the type of a variable or function automatically. For example, if you create a variable called “myNumber”, you don’t have to specify the type of the variable since the compiler can infer it.

Less Boilerplate Code with Kotlin

Programmers often use boilerplate code for certain functions that appear often in a program. For example, if you have a function that takes a value and returns a value, you need a “return” keyword at the end of the function.

The function might be only a few lines of code, but you have to write the boilerplate at the beginning and end of the function. In Kotlin, you can end the function with a “colon”, and you don’t need the “return” keyword. If a function only has one line of code, you can end the function with a “colon” and no “return” keyword.


Kotlin is a mature, modern programming language that is helpful for Android development. It is easy to learn and lets you be more productive with fewer bugs. It is also a great choice for transitioning from Java if you are looking for a new language to learn.

Fortunately, with the right resources and approach, you can get past the initial struggle and soon find yourself swimming in the language and enjoying the benefits of a more efficient development process.

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