While Java is one of the world's most widely used programming languages and is pretty much the official language of Android development, it's not necessarily the best option for your Android projects.
Kotlin streamlines Java coding and fixes the superfluous features that get in the way. Kotlin classes are significantly more compact, less verbose, and easier to read than their Java counterparts.
This resource brings together free courses and tutorials to help you learn Kotlin.
What Is Kotlin?
Kotlin is a modern programming language that compiles to Java bytecode. It is free and open source, and it promises to make coding for Android even more fun.
Kotlin is 100% interoperable with Java. In other words, it can be used together with Java in the same project. This means you can refactor parts of your Java code to Kotlin, and it won't break.
In addition, Kotlin syntax is concise, expressive, simpler, and cleaner. Its precise code allows you to spend more time on solving the actual problem, rather than struggling with verbose syntax.
There are a few factors that make Kotlin a great choice for Android development:
Interchangeability With Java
You can even have Java and Kotlin code existing side by side in the same project, and everything will still compile perfectly.
Easy Learning Curve
Kotlin aims to be an enhancement to Java, rather than a complete rewrite, so many of the skills you've acquired and honed throughout your Java career should still be applicable to your Kotlin projects.
Combine the Best of Functional and Procedural Programming
Why choose between functional and procedural? Kotlin brings you the best of both worlds by combining concepts from both procedural and functional programming.
First-Class Android Studio Support
Android Studio makes configuring Kotlin in your project as straightforward as opening a few menus.
More Concise Code
If you compare a Java class and a Kotlin class that produce the same results, the one written in Kotlin will typically be much shorter. And as every developer knows, less code means fewer bugs!
According to the official Android website, Kotlin helps you avoid null exceptions, thus making Android apps that use Kotlin 20% less likely to crash.
Kotlin From Scratch
In the Kotlin From Scratch series, you'll learn about the language fundamentals: everything from variables to lambda functions and object orientation.
To follow along, you'll need the Kotlin plugin for Android Studio. Alternatively, you could use the online playground or IntelliJ IDEA Community Edition.
1. Variables, Basic Types, and Arrays
In this first tutorial in the Kotlin From Scratch series, you'll learn about the language basics: comments, variables, simple types, arrays, and type inference.
2. Nullability, Loops, and Conditions
In this tutorial, we'll continue to learn the language by looking at nullability, loops, and conditions in Kotlin. You'll learn about loops, ranges, conditions, collections, and packages in Kotlin.
3. Ranges and Collections
Here you'll learn about the ranges and collections API in Kotlin.
4. Packages and Basic Functions
In part 4, you'll discover how to organize code using packages, and then go on to an introduction to functions in Kotlin.
5. More Fun With Functions
Functions are at the heart of Kotlin, so in this tutorial we'll look more closely at them. You'll be amazed at all the cool things you can do with functions in Kotlin!
6. Advanced Functions
Kotlin is a functional language, and that means functions are front and center. The language is packed with features to make coding functions easy and expressive. In this post, you'll learn about extension functions, higher-order functions, closures, and inline functions in Kotlin.
7. Classes and Objects
In this post, you'll get an introduction to object-oriented programming in Kotlin by learning about classes: constructors and properties, casting, and more advanced class features that Kotlin makes easy.
8. Advanced Properties and Classes
In this tutorial, you'll continue to learn even more cool features that Kotlin has for object-oriented programming. You'll learn more about properties and also look into advanced types of classes in Kotlin, late-initialized properties, inline properties, extension properties, data, enum, nested, and sealed classes.
9. Abstract Classes, Interfaces, Inheritance, and Type Alias
In this post, you'll continue to learn about object-oriented programming in Kotlin by learning about abstract classes, interfaces, and inheritance. For a bonus, you'll also learn about type aliases.
- Kotlin From Scratch: Abstract Classes, Interfaces, Inheritance, and Type AliasChike Mgbemena18 Oct 2017
10. Exception Handling
In this post, you'll continue to learn about programming in Kotlin by learning about exceptions and how to handle them.
Hands-on Kotlin Tutorials
The best way to learn is through doing. These tutorials will help you get started coding Android apps in Kotlin and gain a great understanding of the language.
- Coding Functional Android Apps in Kotlin: Getting StartedJessica Thornsby19 Dec 2016
- Coding Functional Android Apps in Kotlin: Lambdas, Null Safety & MoreJessica Thornsby09 Jan 2017
- Code Your First Android Slice and Keep Users EngagedJessica Thornsby05 Jul 2018
- How to Code a Settings Screen in an Android AppChike Mgbemena22 Feb 2018
- How to Code a Bottom Navigation Bar for an Android AppChike Mgbemena22 May 2021
- How to Code a Navigation Drawer for an Android AppEsther Vaati17 Jun 2021
Learning Android Development
To continue learning more about the Kotlin language, visit the Kotlin documentation. Or check out some of our other Android app development posts here on Envato Tuts!
Popular Kotlin Android App Templates
To save time and money when developing Android apps, it is always recommended to use an Android app template. CodeCanyon has a great selection of Kotlin Android templates. Here's a selection of six of the most popular ones: