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

Developing the dictionary app


With the IDE project, build tool, and required libraries sorted out, we can start developing our app.

Preparing the data

Since the dictionary words are stored in a JSON file, we need to parse the data before saving it to a local database.

First, we'll add the class that will represent our data. In the base package (com.packt.quickstart.dictionary), we first add a new package called data. There, we put the DictionaryEntry class, which will be our data model representation:

data class DictionaryEntry(val term: String, val explanation: String)

The class has two properties: the searchable term and the term definition. It'd be also nice to have a readable string representation of this class, so we let the Kotlin compiler generate a toString method for us with its data class.

Since the file of words is around 20 MB in size, to avoid loading that much data in the memory at once and deserializing the whole file in one go, we'll deserialize it manually, entry by entry.

For...