Book Image

Kotlin Quick Start Guide

By : Marko Devcic
Book Image

Kotlin Quick Start Guide

By: Marko Devcic

Overview of this book

Kotlin is a general purpose, object-oriented language that primarily targets the JVM and Android. Intended as a better alternative to Java, its main goals are high interoperability with Java and increased developer productivity. Kotlin is still a new language and this book will help you to learn the core Kotlin features and get you ready for developing applications with Kotlin. This book covers Kotlin features in detail and explains them with practical code examples.You will learn how to set up the environment and take your frst steps with Kotlin and its syntax. We will cover the basics of the language, including functions, variables, and basic data types. With the basics covered, the next chapters show how functions are first-class citizens in Kotlin and deal with the object-oriented side of Kotlin. You will move on to more advanced features of Kotlin. You will explore Kotlin's Standard Library and learn how to work with the Collections API. The book finishes by putting Kotlin in to practice, showing how to build a desktop app. By the end of this book, you will be confident enough to use Kotlin for your next project.
Table of Contents (15 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Classes


To begin with classes, let's take a look how Java would declare a class, with a couple of fields that are initialized in the class constructor. To enforce encapsulation, the class has private fields but provides get and set methods for each field, so they can be accessed and modified from outside:

public final class User {
    private String firstName;
private String lastName;
private int birthYear;

public User(String firstName, String lastName, int birthYear) {
this.firstName = firstName;
this.lastName = lastName;
this.birthYear = birthYear;
}

public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

public int getBirthYear() {
return birthYear;
}

public void setBirthYear(int birthYear) {
this.birthYear = birthYear;
}
}

Now, the same class written in Kotlin would look like this:

class User...