Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Free Learning
Arrow right icon
Kotlin Programming Cookbook
Kotlin Programming Cookbook

Kotlin Programming Cookbook: Explore more than 100 recipes that show how to build robust mobile and web applications with Kotlin, Spring Boot, and Android

Arrow left icon
Profile Icon Aanand Shekhar Roy Profile Icon Rashi Karanpuria
Arrow right icon
€41.99
Full star icon Full star icon Full star icon Half star icon Empty star icon 3.3 (3 Ratings)
Paperback Jan 2018 434 pages 1st Edition
eBook
€22.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m
Arrow left icon
Profile Icon Aanand Shekhar Roy Profile Icon Rashi Karanpuria
Arrow right icon
€41.99
Full star icon Full star icon Full star icon Half star icon Empty star icon 3.3 (3 Ratings)
Paperback Jan 2018 434 pages 1st Edition
eBook
€22.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m
eBook
€22.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/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
OR
Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Table of content icon View table of contents Preview book icon Preview Book

Kotlin Programming Cookbook

Control Flow

The following recipes will be covered in this chapter:

  • Assigning result to an expression using the if keyword
  • Using range with the when expression
  • Using when with custom objects
  • Using trycatch as an expression
  • How to write a swap function in Kotlin using the also function
  • How to throw a custom exception in Kotlin
  • How to make a multiconditional loop in Kotlin

Introduction

Control flows are the basic building block of every programming language. What's different in Kotlin is that you can use a few of those control flows as an expression, such as try-catch, if-else, when, and so on. In this chapter, we will go through some of the control flows offered by Kotlin and learn to use them. Furthermore, we will also see how they provide much more power than Java control flows. So let's get started!

Assigning result to an expression using the if keyword

In Kotlin if is special because it returns values. That is why we can use an if statement to assign values to a result. This removes the need for a ternary operator in Kotlin. Let's see how we can use if statements to assign value.

Getting ready

You need to install a preferred development environment that compiles and runs Kotlin. You can also use the command line for this purpose, for which you need Kotlin compiler installed, along with JDK. I am using the command line for compiling and running my Kotlin code for this recipe.

How to do it...

...

Using range with the when expression

In Kotlin, when is like a super-powered switch control statement. However, that's not all it can do. There's a lot of amazing logic that you can build with the when statement, one example of which is using a range with the when statement. We will take a look at that in this recipe.

Getting ready

You need to install a preferred development environment that compiles and runs Kotlin. You can also use the command line for this purpose, for which you need Kotlin compiler installed, along with JDK. I am using the command line to compile and run my Kotlin code for this recipe.

...

Using when with custom objects

In Kotlin, when is already so powerful but did you know you can also use custom objects in when? Amazing, right? Let's go about implementing it.

Getting ready

You need to install a preferred development environment that compiles and runs Kotlin. You can also use the command line for this purpose, for which you need Kotlin compiler installed, along with JDK. I am using the command line to compile and run my Kotlin code for this recipe.

How to do it...

Create a file and name it whenWithObject.kt, and then, let's try when with a custom...

Using try–catch as an expression

Exceptions in Kotlin are both similar and different compared to those in Java. In Kotlin, Throwable is the superclass of all the exceptions, and every exception has a stack trace, message, and an optional cause.

The structure of trycatch is also similar to that used in Java. In Kotlin, here's how a trycatch statement looks:

try {
// some code to execute
}
catch (e: SomeException) {
// exception handler
}
finally {
// optional finally block
}

At least one catch block is mandatory and the finally block is optional, and so it can be omitted.

In Kotlin, trycatch is special as it enables it to be used as an expression. In this article, we will see how we can use trycatch as an expression.

Getting ready...

How to write a swap function in Kotlin using the also function

Swapping two numbers is one of the most common things you do in programming. Most of the approaches are quite similar in nature: Either you do it using a third variable or using pointers.

In Java, we don't have pointers, so mostly we rely on a third variable.

You can obviously use something as mentioned here, which is just the Kotlin version of Java code:

var a = 1
var b = 2
run { val temp = a; a = b; b = temp }
println(a) // print 2
println(b) // print 1

However, in Kotlin, there is a very quick and intuitive way of doing it. Let's see how!

Getting ready

You need to install a preferred development environment that compiles and runs Kotlin. You can also use...

How to throw a custom exception in Kotlin

Sometimes, there are cases where you want to create your own exception. If you are creating your own exception, it's known as a custom exception or user-defined exception.

These are used to customize the exception according to a specific need, and using this, you can have your own exception and a message. In this recipe, we will see how to create and throw a custom exception in Kotlin.

Getting ready

You need to install a preferred development environment that compiles and runs Kotlin. You can also use the command line for this purpose, for which you need Kotlin compiler installed, along with JDK. I am using IntelliJ IDE to compile and run my Kotlin code for this recipe.

...

How to make a multiconditional loop in Kotlin

Conditional loops are common to any programming language you pick. If you apply multiple conditions on a loop, it is called a multiconditional loop. A simple example of a multiconditional loop in Java is illustrated here:

int[] data = {5,6,7,1,3,4,5,7,12,13};
for(int i=0;i<10&&i<data[i];i++){
System.out.println(data[i]);
}

The preceding code on execution will print out 5, 6, and 7. Let's see how we can use a multiconditional loop in Kotlin. We will be looking at a functional approach to the same thing in Kotlin.

Getting ready

You need to install a preferred development environment that compiles and runs Kotlin. You can also use the command line for this purpose...

Left arrow icon Right arrow icon

Key benefits

  • Practical solutions to your common programming problems with Kotlin 1.1
  • Leverage the functional power of Kotlin to ease your Android application development
  • Learn to use Java code in conjunction with Kotlin

Description

The Android team has announced first-class support for Kotlin 1.1. This acts as an added boost to the language and more and more developers are now looking at Kotlin for their application development. This recipe-based book will be your guide to learning the Kotlin programming language. The recipes in this book build from simple language concepts to more complex applications of the language. After the fundamentals of the language, you will learn how to apply the object-oriented programming features of Kotlin 1.1. Programming with Lambdas will show you how to use the functional power of Kotlin. This book has recipes that will get you started with Android programming with Kotlin 1.1, providing quick solutions to common problems encountered during Android app development. You will also be taken through recipes that will teach you microservice and concurrent programming with Kotlin. Going forward, you will learn to test and secure your applications with Kotlin. Finally, this book supplies recipes that will help you migrate your Java code to Kotlin and will help ensure that it's interoperable with Java.

Who is this book for?

This book will appeal to Kotlin developers keen to find solutions for their common programming problems. Java programming knowledge would be an added advantage.

What you will learn

  • Understand the basics and object-oriented concepts of Kotlin Programming
  • Explore the full potential of collection frameworks in Kotlin
  • Work with SQLite databases in Android, make network calls, and fetch data over a network
  • Use Kotlin s Anko library for efficient and quick Android development
  • Uncover some of the best features of Kotlin: Lambdas and Delegates
  • Set up web service development environments, write servlets, and build RESTful services with Kotlin
  • Learn how to write unit tests, integration tests, and instrumentation/acceptance tests.
Estimated delivery fee Deliver to Slovenia

Premium delivery 7 - 10 business days

€25.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Jan 25, 2018
Length: 434 pages
Edition : 1st
Language : English
ISBN-13 : 9781788472142
Vendor :
JetBrains
Category :
Languages :
Tools :

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
OR
Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Estimated delivery fee Deliver to Slovenia

Premium delivery 7 - 10 business days

€25.95
(Includes tracking information)

Product Details

Publication date : Jan 25, 2018
Length: 434 pages
Edition : 1st
Language : English
ISBN-13 : 9781788472142
Vendor :
JetBrains
Category :
Languages :
Tools :

Packt Subscriptions

See our plans and pricing
Modal Close icon
€18.99 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
€189.99 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
€264.99 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 120.97
Kotlin Programming By Example
€41.99
Hands-On Microservices with  Kotlin
€36.99
Kotlin Programming Cookbook
€41.99
Total 120.97 Stars icon
Banner background image

Table of Contents

15 Chapters
Installation and Working with Environment Chevron down icon Chevron up icon
Control Flow Chevron down icon Chevron up icon
Classes and Objects Chevron down icon Chevron up icon
Functions Chevron down icon Chevron up icon
Object-Oriented Programming Chevron down icon Chevron up icon
Collections Framework Chevron down icon Chevron up icon
Handling File Operations in Kotlin Chevron down icon Chevron up icon
Anko Commons and Extension Function Chevron down icon Chevron up icon
Anko Layouts Chevron down icon Chevron up icon
Databases and Dependency Injection Chevron down icon Chevron up icon
Networking and Concurrency Chevron down icon Chevron up icon
Lambdas and Delegates Chevron down icon Chevron up icon
Testing Chevron down icon Chevron up icon
Web Services with Kotlin 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 Full star icon Half star icon Empty star icon 3.3
(3 Ratings)
5 star 33.3%
4 star 33.3%
3 star 0%
2 star 0%
1 star 33.3%
Luis Espinoza Feb 23, 2018
Full star icon Full star icon Full star icon Full star icon Full star icon 5
It's a great book, it contains a lot of recipes that will help you on your journey as a kotlin developer.
Amazon Verified review Amazon
Amazon Customer Mar 12, 2018
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
I like the variety of recipes, touching all the parts of the Kotlin language, including Anko. What I miss in the book is a little deeper explanation of why things and recipes should be done the way they're done.
Amazon Verified review Amazon
Amazon Customer Oct 12, 2018
Full star icon Empty star icon Empty star icon Empty star icon Empty star icon 1
Book does stand-up to the Mark, what it talks about.It doesn't provide proper information about Kotlin language syntax, Data Types, String, Collection & their uses.In Middle pages contents are not at all proper. Contents are single line vertically running content.Is there any way for Re-Fund for e-books.
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 [email protected] 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 [email protected] 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 [email protected] 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 [email protected] 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 [email protected] 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 [email protected] 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