Search icon CANCEL
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Hands-On Object-Oriented Programming with Kotlin
Hands-On Object-Oriented Programming with Kotlin

Hands-On Object-Oriented Programming with Kotlin: Build robust software with reusable code using OOP principles and design patterns in Kotlin

eBook
$27.98 $39.99
Paperback
$48.99
Subscription
Free Trial
Renews at $19.99p/m

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
Table of content icon View table of contents Preview book icon Preview Book

Hands-On Object-Oriented Programming with Kotlin

Introduction to Object-Oriented Programming

Object-oriented programming is one of the most famous and practical software-development techniques. Traditional procedural programming is tedious and prone to error, especially when it comes to the development of large and complex applications. In this chapter, we will provide a quick introduction to object-oriented programming and its benefits. We will also try to understand why the object-oriented approach is easy to grasp and how it is similar to human nature. We will learn about classes, objects, and constructor declarations. By the end of this chapter, we will be familiar with properties, behaviors, function overloading, the concept of data classes, and how data classes can help to improve application development.

The following topics will be covered in this chapter:

  • Object-oriented programming
  • Syntax of class declaration
  • The...

Technical requirements

Object-oriented programming?

In our day-to-day life, we deal with a number of different objects. Some of these objects talk to us, some move on the road, and some fly in the sky. We naturally observe everything about the characteristics and behaviors of these objects. As an example, let's think about an object with the following properties: it has a couple of doors, four wheels, one steering wheel, brakes, gears, and an engine, it moves on the road, stops when the brakes are applied, and turns left or right when the steering wheel moves. Based on these attributes and behaviors, we can carry out a classification of this object – it belongs to a class called Car. In programming, the technique to design and build an application by focusing on objects that interact with each other is known as object-oriented programming. In the object-oriented paradigm, class and object...

Benefits of object-oriented programming

Old programming languages, such as Assembly or FORTRAN, are not object-oriented languages. Instead, these are procedural programming languages, languages in which a program is written in one long procedure. The data and the logic are coupled together in one place and a program contains a list of routines or subroutines to instruct the computer step by step. This approach is also known as a top-down approach, because instructions are executed one after the other. Procedural programming comes with a number of drawbacks:

  • There is no information-hiding mechanism; data is exposed to the whole system
  • Data and functions are stored in separate memory locations
  • It is difficult to map real-world objects
  • The code cannot be reused; each module or instruction set requires its own tightly coupled routine
  • The code cannot be extended; it is difficult to...

Classes in Kotlin

In Kotlin, a class can be defined with the class keyword. Let's take a look at how to declare a class and how to add attributes to it. In Kotlin, a class can be declared as follows:

class Person 

Compared to other programming languages, creating a class in Kotlin is very easy. All we need to do is open our IDE and create a person class with three attributes—name, age, and height. The name is a variable of the String type, age is a variable of the Integer type, and height is a variable of the Double type:

class Person {
var name: String
var age : Int
var height : Double
}

We have now declared a Person class with three attributes enclosed in brackets. After writing this code, we will notice that compiler has immediately thrown a Property not initialized error, because we haven't decided that how these properties will be initialized. Let...

Properties – first-class citizens

Each class contains different attributes. The Person class, for example, contains the name, age, and height attributes. When a Person class is declared in Java or another programming language, these attributes are called fields of the class. When these fields are accessed by their corresponding getter and setter methods, they are called properties. To understand this concept in detail, create a Person class in Java, as follows:

public class Person {

String name;
int age;
double height;

Person(String n, int a, double h){
name = n;
age = a;
height = h;
}

public double getHeight() {
return height;
}

public void setHeight(double height) {
this.height = height;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public...

Constructing a class with a constructor

When an object is created, all class members have to have an initial value. We can either initialize a property directly or the initial values can be provided by a constructor. A constructor is a special type of function that is used to initialize the properties of the class.

A constructor is invoked when the object is created, or, more specifically, when the space is allocated in the memory. This special function has two important characteristics:

  • Constructors can be declared with the constructor keyword
  • Constructors don't contain any return types, not even Units

In this section, we will learn about all of the different kinds of constructors that are provided by Kotlin. Let's start with the default constructor.

Default constructor...

What are data classes?

During the application's development, classes are used quite often as a data-holder, not to carry out complex tasks. These classes only contain properties for reading and writing purposes. The person class is a simple example of a class used as a data-holder. If the sole responsibility of the class is to handle data, programmers may want the class to be able to carry out additional functionalities:

  • The data should be in a well-presented format
  • We should be able to compare object properties
  • We should be able to clone existing objects

All these functionalities can be written by the programmer. Alternatively, an advanced IDE could generate this code automatically. Either way, the project would be filled with boilerplate code. Just as it automatically generates getters and setters, Kotlin assumes the responsibility for generating all of these functions...

Classes and functions

In this section, we will have a quick look at how behaviors and functions can be implemented. We will continue with our Person class, which has three behaviors—speak, eat, and walk.

As we know, class behaviors are represented by functions. We can declare a function within the class body:

  1. Create a class with a primary constructor and add the speak() function by using fun keyword. When a function is declared in the class body, it becomes class behavior:
class Person (val name: String, var age : Int , var height : Double) {
fun speak() {
println("My name is $name , i am $age years old and I am $height feet tall")
}
}

fun main(args: Array<String>) {
val abid = Person("Abid", 40, 6.0)
abid.speak()
}
  1. Create an object of the Person class and call the speak function using the . operator. Execute this program and...

Summary

In this chapter, we learned about object-oriented programming and why it is better than procedural programming. We started the chapter by exploring classes and learning how to declare them. We also discussed the properties and behavior of classes, and why properties are known as first-class citizens. Then, we had a detailed discussion about data classes, constructors, and how parameterized constructors help us to write clean code. In the last section of this chapter, we covered functions and function overloading. In the next chapter, we will look at some more advanced topics and their implementations.

Questions

  1. What is the difference between a class and an object?
  2. What is an attribute and the behavior of the class?
  3. What is a constructor and how many types of constructors are available?
  4. What is function overloading?
  5. What are data classes and why are they beneficial?

Further reading

Left arrow icon Right arrow icon
Download code icon Download Code

Key benefits

  • A practical guide to understand objects and classes in Kotlin
  • Learn to write asynchronous, non-blocking codes with Kotlin coroutines
  • Explore Encapsulation, Inheritance, Polymorphism, and Abstraction in Kotlin

Description

Kotlin is an object-oriented programming language. The book is based on the latest version of Kotlin. The book provides you with a thorough understanding of programming concepts, object-oriented programming techniques, and design patterns. It includes numerous examples, explanation of concepts and keynotes. Where possible, examples and programming exercises are included. The main purpose of the book is to provide a comprehensive coverage of Kotlin features such as classes, data classes, and inheritance. It also provides a good understanding of design pattern and how Kotlin syntax works with object-oriented techniques. You will also gain familiarity with syntax in this book by writing labeled for loop and when as an expression. An introduction to the advanced concepts such as sealed classes and package level functions and coroutines is provided and we will also learn how these concepts can make the software development easy. Supported libraries for serialization, regular expression and testing are also covered in this book. By the end of the book, you would have learnt building robust and maintainable software with object oriented design patterns in Kotlin.

Who is this book for?

This book is for programmers and developers who wish to learn Object-oriented programming principles and apply them to build robust and scalable applications. Basic knowledge in Kotlin programming is assumed

What you will learn

  • Get an overview of the Kotlin programming language
  • Discover Object-oriented programming techniques in Kotlin
  • Understand Object-oriented design patterns
  • Uncover multithreading by Kotlin way
  • Understand about arrays and collections
  • Understand the importance of object-oriented design patterns
  • Understand about exception handling and testing in OOP with Kotlin
Estimated delivery fee Deliver to Malaysia

Standard delivery 10 - 13 business days

$8.95

Premium delivery 5 - 8 business days

$45.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Oct 31, 2018
Length: 370 pages
Edition : 1st
Language : English
ISBN-13 : 9781789617726
Category :
Languages :

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
Estimated delivery fee Deliver to Malaysia

Standard delivery 10 - 13 business days

$8.95

Premium delivery 5 - 8 business days

$45.95
(Includes tracking information)

Product Details

Publication date : Oct 31, 2018
Length: 370 pages
Edition : 1st
Language : English
ISBN-13 : 9781789617726
Category :
Languages :

Packt Subscriptions

See our plans and pricing
Modal Close icon
$19.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
$199.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just $5 each
Feature tick icon Exclusive print discounts
$279.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just $5 each
Feature tick icon Exclusive print discounts

Frequently bought together


Stars icon
Total $ 136.97
Hands-On Object-Oriented Programming with Kotlin
$48.99
Learning Concurrency in Kotlin
$48.99
Hands-On Data Structures and Algorithms with Kotlin
$38.99
Total $ 136.97 Stars icon

Table of Contents

13 Chapters
Getting Started with Kotlin Chevron down icon Chevron up icon
Introduction to Object-Oriented Programming Chevron down icon Chevron up icon
The Four Pillars of Object-Oriented Programming Chevron down icon Chevron up icon
Classes - Advanced Concepts Chevron down icon Chevron up icon
Data Collection, Iterators, and Filters Chevron down icon Chevron up icon
Object-Oriented Patterns in Kotlin Chevron down icon Chevron up icon
Coroutines - a Lightweight Thread? Chevron down icon Chevron up icon
Interoperability Chevron down icon Chevron up icon
Regular Expression and Serialization in Kotlin Chevron down icon Chevron up icon
Exception Handling Chevron down icon Chevron up icon
Testing in Object-Oriented Programming with Kotlin Chevron down icon Chevron up icon
Assessments Chevron down icon Chevron up icon
Other Books You May Enjoy Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.5
(2 Ratings)
5 star 0%
4 star 0%
3 star 50%
2 star 50%
1 star 0%
AntoineLyon Apr 18, 2022
Full star icon Full star icon Empty star icon Empty star icon Empty star icon 2
Même si la structure est intéressante, ce livre a un énorme défaut, il est plein de fautes de frappe ou d'erreurs de code. Quand on traite de code informatique, ce sont des erreurs inacceptables; on a l'impression que ce n'est pas un informaticien qui a relu. Ces erreurs changent parfois le sens du code, des inversions de paramètres, des méthodes inexistantes, et j'en passe. Si on a un background de développeur, on arrive à corriger par soi même, mais je ne recommande pas ce livre comme méthode d'apprentissage au langage Kotlin.
Amazon Verified review Amazon
BA Jul 17, 2019
Full star icon Full star icon Full star icon Empty star icon Empty star icon 3
I had previous experience with Kotlin and wanted to get a more in depth view of the landguage. However the book doesn't go very deep at all, it goes over many subjects quite briefly.If you're an absolute Kotlin beginner then it's good I guess, if not you might learn something, but don't expect a good return for the invested time.
Amazon Verified review Amazon
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is the delivery time and cost of print book? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela
What is custom duty/charge? Chevron down icon Chevron up icon

Customs duty are charges levied on goods when they cross international borders. It is a tax that is imposed on imported goods. These duties are charged by special authorities and bodies created by local governments and are meant to protect local industries, economies, and businesses.

Do I have to pay customs charges for the print book order? Chevron down icon Chevron up icon

The orders shipped to the countries that are listed under EU27 will not bear custom charges. They are paid by Packt as part of the order.

List of EU27 countries: www.gov.uk/eu-eea:

A custom duty or localized taxes may be applicable on the shipment and would be charged by the recipient country outside of the EU27 which should be paid by the customer and these duties are not included in the shipping charges been charged on the order.

How do I know my custom duty charges? Chevron down icon Chevron up icon

The amount of duty payable varies greatly depending on the imported goods, the country of origin and several other factors like the total invoice amount or dimensions like weight, and other such criteria applicable in your country.

For example:

  • If you live in Mexico, and the declared value of your ordered items is over $ 50, for you to receive a package, you will have to pay additional import tax of 19% which will be $ 9.50 to the courier service.
  • Whereas if you live in Turkey, and the declared value of your ordered items is over € 22, for you to receive a package, you will have to pay additional import tax of 18% which will be € 3.96 to the courier service.
How can I cancel my order? Chevron down icon Chevron up icon

Cancellation Policy for Published Printed Books:

You can cancel any order within 1 hour of placing the order. Simply contact customercare@packt.com with your order details or payment transaction id. If your order has already started the shipment process, we will do our best to stop it. However, if it is already on the way to you then when you receive it, you can contact us at customercare@packt.com using the returns and refund process.

Please understand that Packt Publishing cannot provide refunds or cancel any order except for the cases described in our Return Policy (i.e. Packt Publishing agrees to replace your printed book because it arrives damaged or material defect in book), Packt Publishing will not accept returns.

What is your returns and refunds policy? Chevron down icon Chevron up icon

Return Policy:

We want you to be happy with your purchase from Packtpub.com. We will not hassle you with returning print books to us. If the print book you receive from us is incorrect, damaged, doesn't work or is unacceptably late, please contact Customer Relations Team on customercare@packt.com with the order number and issue details as explained below:

  1. If you ordered (eBook, Video or Print Book) incorrectly or accidentally, please contact Customer Relations Team on customercare@packt.com within one hour of placing the order and we will replace/refund you the item cost.
  2. Sadly, if your eBook or Video file is faulty or a fault occurs during the eBook or Video being made available to you, i.e. during download then you should contact Customer Relations Team within 14 days of purchase on customercare@packt.com who will be able to resolve this issue for you.
  3. You will have a choice of replacement or refund of the problem items.(damaged, defective or incorrect)
  4. Once Customer Care Team confirms that you will be refunded, you should receive the refund within 10 to 12 working days.
  5. If you are only requesting a refund of one book from a multiple order, then we will refund you the appropriate single item.
  6. Where the items were shipped under a free shipping offer, there will be no shipping costs to refund.

On the off chance your printed book arrives damaged, with book material defect, contact our Customer Relation Team on customercare@packt.com within 14 days of receipt of the book with appropriate evidence of damage and we will work with you to secure a replacement copy, if necessary. Please note that each printed book you order from us is individually made by Packt's professional book-printing partner which is on a print-on-demand basis.

What tax is charged? Chevron down icon Chevron up icon

Currently, no tax is charged on the purchase of any print book (subject to change based on the laws and regulations). A localized VAT fee is charged only to our European and UK customers on eBooks, Video and subscriptions that they buy. GST is charged to Indian customers for eBooks and video purchases.

What payment methods can I use? Chevron down icon Chevron up icon

You can pay with the following card types:

  1. Visa Debit
  2. Visa Credit
  3. MasterCard
  4. PayPal
What is the delivery time and cost of print books? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela