Beginner’s Guide to Kotlin Programming

This textbook assumes very little knowledge of programming so whether you have dabbled with a little JavaScript, played with a bit of Python, written Java or have virtually no programming experience at all you will find that it is for you.

The first part of the book introduces Kotlin program structures as well as conditional flow of control features such as if and when expressions as well as iteration loops such as for, while and do-while. Subsequent chapters explain how functions are implemented in Kotlin and introduce concepts from functional programming such as higher order functions and curried functions.

The second part focusses on object oriented programming techniques, these include classes, inheritance, abstraction and interfaces. The third part presents container data types such as Arrays, and collections including Lists, Sets and Maps and the fourth part considers concurrency and parallelism using Kotlin coroutines. The book concludes with an introduction to Android mobile application development using Kotlin. Clear steps are provided explaining how to set up your environment and get started writing your own Kotlin programs.

An important aspect of the book is teaching by example and there are many examples presented throughout the chapters. These examples are supported by a public GitHub repository that provides complete working code as well as sample solutions to the chapter exercises. This helps illustrate how to write well structured, clear, idiomatic Kotlin to build real applications.

Table of Contents

1 Introduction

Part I Kotlin Programming

2 A First Kotlin Program

3 Flow of Control

4 Number Guessing Game

5 Functions in Kotlin

6 Higher Order Functions

7 Curried Functions

Part II Object-Oriented Kotlin

8 Kotlin Classes

9 Objects and Companion Objects

10 Further Kotlin Properties

11 Scope and Conditional Functions

12 Class Inheritance

13 Abstract Classes

14 Interfaces, Delegation and Enumerated Types

15 Packages

16 Nested/Inner Types

17 Data Classes

18 Sealed and Inline Classes and Typealias

19 Operator Overloading

20 Error and Exception Handling

21 Extension Functions and Properties

Part III Data Containers

22 Arrays

23 Collections

24 Lists

25 Sets

26 Maps

27 Pairs and Triples

28 Generic Types

29 Functional Programming and Containers

Part IV Concurrent Kotlin

30 Coroutines

31 Coroutine Channel Communications

Part V Android Development

32 Android Overview

33 Applications and Activities

34 Android Layouts and Events

35 Android Tic Tac Toe

About the Author

John Hunt is a technology trainer, consultant, mentor and author who nearly 40 years’ experience within the computing industry. He has worked extensively in Object Oriented and Functional technologies using language from Python through Java to Kotlin. John was first involved with Kotlin while working with a FinTech company in 2016. Since then, John has seen the interest in Kotlin grow and grow and in recent years has found numerous clients have been turning from Java to Kotlin both for server side and Android mobile applications.