Search icon Close icon
Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Checkout

Change country

Modal Close icon
Country selected Country selected
country flag United States
Country selected
country flag Great Britain
Country selected
country flag India
Country selected
country flag Germany
Country selected
country flag France
Country selected
country flag Canada
Country selected
country flag Russia
Country selected
country flag Spain
Country selected
country flag Brazil
Country selected
country flag Australia
Country selected
country flag Singapore
Country selected
country flag Hungary
Country selected
country flag Philippines
Country selected
country flag Mexico
Country selected
country flag Thailand
Country selected
country flag Ukraine
Country selected
country flag Luxembourg
Country selected
country flag Estonia
Country selected
country flag Lithuania
Country selected
country flag Norway
Country selected
country flag Chile
Country selected
country flag South Korea
Country selected
country flag Ecuador
Country selected
country flag Colombia
Country selected
country flag Taiwan
Country selected
country flag Switzerland
Country selected
country flag Indonesia
Country selected
country flag Cyprus
Country selected
country flag Denmark
Country selected
country flag Finland
Country selected
country flag Poland
Country selected
country flag Malta
Country selected
country flag Czechia
Country selected
country flag New Zealand
Country selected
country flag Austria
Country selected
country flag Turkey
Country selected
country flag Sweden
Country selected
country flag Italy
Country selected
country flag Egypt
Country selected
country flag Belgium
Country selected
country flag Portugal
Country selected
country flag Slovenia
Country selected
country flag Ireland
Country selected
country flag Romania
Country selected
country flag Greece
Country selected
country flag Argentina
Country selected
country flag Malaysia
Country selected
country flag South Africa
Country selected
country flag Netherlands
Country selected
country flag Bulgaria
Country selected
country flag Latvia
Country selected
country flag Japan
Country selected
country flag Slovakia
Country selected
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Home > Mobile > Android Development > Android Development with Kotlin
Android Development with Kotlin
Android Development with Kotlin

Android Development with Kotlin: Enhance your skills for Android development using Kotlin

Arrow left icon
Profile Icon Marcin Moskala Profile Icon Igor Wojda
Arrow right icon
$48.99
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.6 (5 Ratings)
Paperback Aug 2017 440 pages 1st Edition
eBook
$9.99 $39.99
Paperback
$48.99
Subscription
Free Trial
Renews at $19.99p/m
Arrow left icon
Profile Icon Marcin Moskala Profile Icon Igor Wojda
Arrow right icon
$48.99
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.6 (5 Ratings)
Paperback Aug 2017 440 pages 1st Edition
eBook
$9.99 $39.99
Paperback
$48.99
Subscription
Free Trial
Renews at $19.99p/m
eBook
$9.99 $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
OR

Contact Details

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

Android Development with Kotlin

Laying a Foundation

This chapter is largely devoted to the fundamental building blocks that are core elements of the Kotlin programming language. Each one may seem insignificant by itself, but combined together, they create really powerful language constructs. We will discuss the Kotlin type system that introduces strict null safety and smart casts. Also, we will see a few new operators in the JVM world, and many improvements compared to Java. We will also present new ways to handle application flows and deal with equality in a unified way.

In this chapter, we will cover the following topics:

  • Variables, values, and constants
  • Type inference
  • Strict null safety
  • Smart casts
  • Kotlin data types
  • Control structures
  • Exceptions handling

Variables

In Kotlin, we have two types of variables: var and val. The first one, var, is a mutable reference (read-write) that can be updated after initialization. The var keyword is used to define a variable in Kotlin. It is equivalent to a normal (non-final) Java variable. If our variable needs to change at some point, we should declare it using the var keyword. Let's look at an example of a variable declaration:

    fun main(args: Array<String>) { 
        var fruit: String =  "orange" //1 
        fruit  = "banana" //2 
    }
  1. Create a fruit variable and initialize it with the vale of the orange variable.
  2. Reinitialize the fruit variable with the value of the banana variable.

The second type of variable is a read-only reference. This type of variable cannot be reassigned after initialization.

The val keyword can contain...

Type inference

As we saw in previous examples, unlike Java, the Kotlin type is defined after the variable name:

    var title: String

At first glance, this may look strange to Java developers, but this construct is a building block of a very important feature of Kotlin called type inference. Type inference means that the compiler can infer type from context (the value of an expression assigned to a variable). When variable declaration and initialization is performed together (single line), we can omit the type declaration. Let's look at the following variable definition:

    var title: String = "Kotlin"

The type of the title variable is String, but do we really need an implicit type declaration to determine variable type? On the right side of the expression, we have a string, Kotlin and we are assigning it to a variable, title, defined on the left...

Strict null safety

According to Agile Software Assessment (http://p3.snf.ch/Project-144126) research, a missing null check is the most frequent pattern of bugs in Java systems. The biggest source of errors in Java is NullPointerExceptions. It's so big that speaking at a conference in 2009, Sir Tony Hoare apologized for inventing the null reference, calling it a billion-dollar mistake (https://en.wikipedia.org/wiki/Tony_Hoare).

To avoid NullPointerException, we need to write defensive code that checks if an object is null before using it. Many modern programming languages, including Kotlin, made steps to convert runtime errors into compile time errors to improve programming language safety. One of the ways to do it in Kotlin is by adding nullability safeness mechanisms to language type systems. This is possible because the Kotlin type system distinguishes between references...

Nullability and Java

We know that Kotlin requires us to explicitly define references that can hold null values. Java on the other hand is much more lenient about nullability, so we may wonder how Kotlin handles types coming from Java (basically the whole Android SDK and libraries written in Java). Whenever possible, the Kotlin compiler will determine type nullability from the code and represent types as actual nullable or non-nullable types using nullability annotations.

The Kotlin compiler supports several flavors of nullability annotations, including:
  • Android (com.android.annotations and android.support.annotations)
  • JetBrains (@Nullable and @NotNull from the org.jetbrains.annotations package)
  • JSR-305 (Javax.annotation)
We can find the full list in the Kotlin compiler source code (https://github.com/JetBrains/kotlin/blob/master/core/descriptor.loader.Java/src/org/jetbrains...

Casts

The casting concept is supported by many programming languages. Basically, casting is a way to convert an object of one particular type into another type. In Java, we need to cast an object explicitly before accessing its member, or cast it and store it in the variable of the casted type. Kotlin simplifies concept of casting and moves it to the next level by introducing smart casts.

In Kotlin, we can perform a few types of cast:

  • Cast objects to different types explicitly (safe cast operator)
  • Cast objects to different types, or nullable types to non-nullable types, implicitly (smart cast mechanism)

Safe/unsafe cast operator

In strongly typed languages, such as Java or Kotlin, we need to convert values from one type...

Variables

In Kotlin, we have two types of variables: var and val. The first one, var, is a mutable reference (read-write) that can be updated after initialization. The var keyword is used to define a variable in Kotlin. It is equivalent to a normal (non-final) Java variable. If our variable needs to change at some point, we should declare it using the var keyword. Let's look at an example of a variable declaration:

    fun main(args: Array<String>) { 
        var fruit: String =  "orange" //1 
        fruit  = "banana" //2 
    }
  1. Create a fruit variable and initialize it with the vale of the orange variable.
  2. Reinitialize the fruit variable with the value of the banana variable.

The second type of variable is a read-only reference. This type of variable cannot be reassigned after initialization.

Note

The val keyword can contain a custom getter, so technically it can return different objects on each access. In other words, we can't guarantee that the reference to the underlying object is...

Type inference

As we saw in previous examples, unlike Java, the Kotlin type is defined after the variable name:

    var title: String

At first glance, this may look strange to Java developers, but this construct is a building block of a very important feature of Kotlin called type inference. Type inference means that the compiler can infer type from context (the value of an expression assigned to a variable). When variable declaration and initialization is performed together (single line), we can omit the type declaration. Let's look at the following variable definition:

    var title: String = "Kotlin"

The type of the title variable is String, but do we really need an implicit type declaration to determine variable type? On the right side of the expression, we have a string, Kotlin and we are assigning it to a variable, title, defined on the left-hand side of the expression.

We specified a variable type as String, but it was obvious, because this is the same type as the type of assigned expression...

Strict null safety

According to Agile Software Assessment(http://p3.snf.ch/Project-144126) research, a missing null check is the most frequent pattern of bugs in Java systems. The biggest source of errors in Java is NullPointerExceptions. It's so big that speaking at a conference in 2009, Sir Tony Hoare apologized for inventing the null reference, calling it a billion-dollar mistake (https://en.wikipedia.org/wiki/Tony_Hoare).

To avoid NullPointerException, we need to write defensive code that checks if an object is null before using it. Many modern programming languages, including Kotlin, made steps to convert runtime errors into compile time errors to improve programming language safety. One of the ways to do it in Kotlin is by adding nullability safeness mechanisms to language type systems. This is possible because the Kotlin type system distinguishes between references that can hold null (nullable references) and those that cannot (non-nullable references). This single feature of Kotlin...

Nullability and Java

We know that Kotlin requires us to explicitly define references that can hold null values. Java on the other hand is much more lenient about nullability, so we may wonder how Kotlin handles types coming from Java (basically the whole Android SDK and libraries written in Java). Whenever possible, the Kotlin compiler will determine type nullability from the code and represent types as actual nullable or non-nullable types using nullability annotations.

Note

The Kotlin compiler supports several flavors of nullability annotations, including:

  • Android (com.android.annotations and android.support.annotations)
  • JetBrains (@Nullable and @NotNull from the org.jetbrains.annotations package)
  • JSR-305 (Javax.annotation)

We can find the full list in the Kotlin compiler source code (https://github.com/JetBrains/kotlin/blob/master/core/descriptor.loader.Java/src/org/jetbrains/kotlin/load/Java/JvmAnnotationNames.kt).

We have seen this previously in Activity's onCreate method, where the savedInstanceState...

Casts

The casting concept is supported by many programming languages. Basically, casting is a way to convert an object of one particular type into another type. In Java, we need to cast an object explicitly before accessing its member, or cast it and store it in the variable of the casted type. Kotlin simplifies concept of casting and moves it to the next level by introducing smart casts.

In Kotlin, we can perform a few types of cast:

  • Cast objects to different types explicitly (safe cast operator)
  • Cast objects to different types, or nullable types to non-nullable types, implicitly (smart cast mechanism)

Safe/unsafe cast operator

In strongly typed languages, such as Java or Kotlin, we need to convert values from one type to another explicitly using the cast operator. A typical casting operation is taking an object of one particular type and turning it into another object type that is its supertype (upcasting), subtype (downcasting), or interface. Let's start with a small reminder of casting that...

Primitive data types

In Kotlin, everything is an object (reference type, not primitive type). We don't find primitive types, like the ones we can use in Java. This reduces code complexity. We can call methods and properties on any variable. For example, this is how we can convert the Int variable to a Char:

    var code: Int = 75 
    code.toChar()

Usually (whenever it is possible), under the hood types such as Int, Long, or Char are optimized (stored as primitive types) but we can still call methods on them as on any other objects.

By default, the Java platform stores numbers as JVM primitive types, but when a nullable number reference (for example, Int?), is needed or generics are involved, Java uses boxed representation. Boxing means wrapping a primitive type into a corresponding boxed primitive type. This means that the instance behaves as an object. Examples of Java boxed representations of primitive types are int versus Integer or a long versus Long Since Kotlin is compiled to JVM bytecode...

Composite data types

Let's discuss more complex types built into Kotlin. Some data types have major improvements compared to Java, while others are totally new.

Strings

Strings in Kotlin behave in a similar way as in Java, but they have a few nice improvements.

To start to access characters at a specified index, we can use the indexing operator and access characters the same way we access array elements:

    val str = "abcd" 
    println (str[1]) // Prints: b

We also have access to various extensions defined in the Kotlin standard library, which make working with strings easier:

    val str = "abcd" 
    println(str.reversed()) // Prints: dcba 
    println(str.takeLast(2)) // Prints: cd 
    println("john@test.com".substringBefore("@")) // Prints: john 
    println("john@test.com".startsWith("@")) // Prints: false

This is exactly the same String class as in Java, so these methods are not part of String class. They were defined as extensions. We will learn more about extensions in Chapter 7, Extension...

Statements versus expressions

Kotlin utilizes expressions more widely than Java, so it is important to know the difference between a statement and an expression. A program is basically a sequence of statements and expressions. An expression produces a value, which can be used as part of another expression, variable assignment, or function parameter. An expression is a sequence of one or more operands (data that is manipulated) and zero or more operators (a token that represents a specific operation) that can be evaluated to a single value:

Let's review some examples of expressions from Kotlin:

Expression (produces a value)

Assigned value

Expression of type

a = true

true

Boolean

a = "foo" + "bar"

"foobar"

String

a = min(2, 3)

2

Integer

a = computePosition().getX()

Value returned by the getX method

Integer

 

Statements, on the other hand, perform an action and cannot be assigned to a variable, because they simply don't have a value. Statements can contain language keywords that are used to define classes (class...

Left arrow icon

Page 1 of 14

Right arrow icon
Download code icon Download Code

Key benefits

  • • Leverage specific features of Kotlin to ease Android application development
  • • Write code based on both object oriented and functional programming to build robust applications
  • • Filled with various practical examples so you can easily apply your knowledge to real world scenarios
  • • Identify the improved way of dealing with common Java patterns

Description

Nowadays, improved application development does not just mean building better performing applications. It has become crucial to find improved ways of writing code. Kotlin is a language that helps developers build amazing Android applications easily and effectively. This book discusses Kotlin features in context of Android development. It demonstrates how common examples that are typical for Android development, can be simplified using Kotlin. It also shows all the benefits, improvements and new possibilities provided by this language. The book is divided in three modules that show the power of Kotlin and teach you how to use it properly. Each module present features in different levels of advancement. The first module covers Kotlin basics. This module will lay a firm foundation for the rest of the chapters so you are able to read and understand most of the Kotlin code. The next module dives deeper into the building blocks of Kotlin, such as functions, classes, and function types. You will learn how Kotlin brings many improvements to the table by improving common Java concepts and decreasing code verbosity. The last module presents features that are not present in Java. You will learn how certain tasks can be achieved in simpler ways thanks to Kotlin. Through the book, you will learn how to use Kotlin for Android development. You will get to know and understand most important Kotlin features, and how they can be used. You will be ready to start your own adventure with Android development with Kotlin.

Who is this book for?

This book is for developers who have a basic understanding of Java language and have 6-12 months of experience with Android development and developers who feel comfortable with OOP concepts.

What you will learn

  • ? Run a Kotlin application and understand the integration with Android Studio
  • ? Incorporate Kotlin into new/existing Android Java based project
  • ? Learn about Kotlin type system to deal with null safety and immutability
  • ? Define various types of classes and deal with properties
  • ? Define collections and transform them in functional way
  • ? Define extensions, new behaviours to existing libraries and Android framework classes
  • ? Use generic type variance modifiers to define subtyping relationship between generic types
  • ? Build a sample application
Estimated delivery fee Deliver to United States

Economy delivery 10 - 13 business days

Free $6.95

Premium delivery 6 - 9 business days

$21.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Aug 30, 2017
Length: 440 pages
Edition : 1st
Language : English
ISBN-13 : 9781787123687
Category :
Mobile
Languages :
Java
Concepts :
Android Development
Tools :
Android

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

Contact Details

Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Estimated delivery fee Deliver to United States

Economy delivery 10 - 13 business days

Free $6.95

Premium delivery 6 - 9 business days

$21.95
(Includes tracking information)

Product Details

Publication date : Aug 30, 2017
Length: 440 pages
Edition : 1st
Language : English
ISBN-13 : 9781787123687
Category :
Mobile
Languages :
Java
Concepts :
Android Development
Tools :
Android

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
START FREE TRIAL
BUY NOW
$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
START FREE TRIAL
BUY NOW
$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
START FREE TRIAL
BUY NOW

Frequently bought together

Programming Kotlin
Programming Kotlin
Read more
Jan 2017 420 pages
Full star icon 3.4 (7)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $48.99
$9.99 $39.99
$48.99
Mastering Android Development with Kotlin
Mastering Android Development with Kotlin
Read more
Nov 2017 378 pages
Full star icon 2.7 (11)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $48.99
$9.99 $39.99
$48.99
Android Development with Kotlin
Android Development with Kotlin
Read more
Aug 2017 440 pages
Full star icon 2.6 (5)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $48.99
$9.99 $39.99
$48.99
Stars icon
Total $ 146.97
Programming Kotlin
$48.99
Mastering Android Development with Kotlin
$48.99
Android Development with Kotlin
$48.99
Total $ 146.97 Stars icon
Banner background image

Table of Contents

9 Chapters
Beginning Your Kotlin Adventure Chevron down icon Chevron up icon
Beginning Your Kotlin Adventure
Say hello to Kotlin
Awesome Kotlin examples
Dealing with Kotlin code
Kotlin under the hood
More reasons to use Kotlin
Summary
Laying a Foundation Chevron down icon Chevron up icon
Laying a Foundation
Variables
Type inference
Strict null safety
Nullability and Java
Casts
Primitive data types
Composite data types
Statements versus expressions
Control flow
Exceptions
Compile-time constants
Delegates
Summary
Playing with Functions Chevron down icon Chevron up icon
Playing with Functions
Basic function declaration and usage
Vararg parameter
Single-expression functions
Tail-recursive functions
Different ways of calling a function
Top-level functions
Top-level functions under the hood
Local functions
Nothing return type
Summary
Classes and Objects Chevron down icon Chevron up icon
Classes and Objects
Classes
Properties
Constructors
Inheritance
Interfaces
Data classes
Operator overloading
Object declaration
Object expression
Companion objects
Enum classes
Infix calls for named methods
Visibility modifiers
Sealed classes
Nested classes
Import aliases
Summary
Functions as First-Class Citizens Chevron down icon Chevron up icon
Functions as First-Class Citizens
Function types
Anonymous functions
Lambda expressions
Higher-order functions
Combination of named arguments and lambda expressions
The last lambda in an argument convention
Java SAM support in Kotlin
Named Kotlin function types
Underscore for unused variables
Destructuring in lambda expressions
Inline functions
Function references
Summary
Generics Are Your Friends Chevron down icon Chevron up icon
Generics Are Your Friends
Generics
Generic constraints
Variance
Type erasure
Star-projections
Type parameter naming convention
Summary
Extension Functions and Properties Chevron down icon Chevron up icon
Extension Functions and Properties
Extension functions
Extension properties
Member extension functions and properties
Generic extension functions
Function literals with a receiver
Summary
Delegates Chevron down icon Chevron up icon
Delegates
Class delegation
Property delegation
Summary
Making Your Marvel Gallery Application Chevron down icon Chevron up icon
Making Your Marvel Gallery Application
Marvel Gallery
Summary

Recommendations for you

Left arrow icon
Transformers for Natural Language Processing
Transformers for Natural Language Processing
Read more
Mar 2022 602 pages
Full star icon 3.8 (28)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $89.99
$9.99 $71.99
$89.99
The Ultimate iOS Interview Playbook
The Ultimate iOS Interview Playbook
Read more
Aug 2023 320 pages
Full star icon 4.7 (19)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $34.99
$9.99 $27.99
$34.99
Android Programming for Beginners
Android Programming for Beginners
Read more
Apr 2021 742 pages
Full star icon 4.2 (12)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $43.99
$9.99 $35.99
$43.99
Swift Cookbook
Swift Cookbook
Read more
Jun 2024 422 pages
Full star icon 5 (3)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $39.99
$9.99 $31.99
$39.99
Kickstart Modern Android Development with Jetpack and Kotlin
Kickstart Modern Android Development with Jetpack and Kotlin
Read more
May 2022 472 pages
Full star icon 4.9 (10)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $46.99
$9.99 $37.99
$46.99
Mastering iOS 18 Development
Mastering iOS 18 Development
Read more
Nov 2024 418 pages
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $41.99
$9.99 $33.99
$41.99
Thriving in Android Development Using Kotlin
Thriving in Android Development Using Kotlin
Read more
Jul 2024 410 pages
Full star icon 5 (5)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $54.99
$9.99 $43.99
$54.99
Mastering Kotlin for Android 14
Mastering Kotlin for Android 14
Read more
Apr 2024 370 pages
Full star icon 5 (8)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $39.99
$9.99 $31.99
$39.99
Apps and Services with .NET 8
Apps and Services with .NET 8
Read more
Dec 2023 798 pages
Full star icon 4.8 (22)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $49.99
$9.99 $39.99
$49.99
Flutter Design Patterns and Best Practices
Flutter Design Patterns and Best Practices
Read more
Sep 2024 362 pages
Full star icon 5 (3)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $44.99
$9.99 $35.99
$44.99
Right arrow icon

Customer reviews

Rating distribution
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.6
(5 Ratings)
5 star 20%
4 star 0%
3 star 20%
2 star 40%
1 star 20%
Mikolaj Leszczynski Sep 21, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Excellent book. This is for Android developers who would like to learn how to apply Kotlin paradigms to typical Android development patterns. Makes for a very practical approach to teaching Kotlin.
Amazon Verified review Amazon
Amazon Customer Oct 07, 2017
Full star icon Full star icon Full star icon Empty star icon Empty star icon 3
Good explanation of Kotlin and advantages over Java. I expected more Android references given the book title so that aspect is a little underwhelming since I am primarily concerned with learning Kotlin for Android development. Though, the last chapter is dedicated to building a gallery app (which I've yet to reach).English is not great, and the grammatical errors don't help, but it is still readable overall. Definitely seems like a number of the issues should have been caught prior to publishing.Overall, so far, I am pleased with the content. My rating may change from a 3 star once I finish reading the entire book.
Amazon Verified review Amazon
Bob Mann Sep 30, 2017
Full star icon Full star icon Empty star icon Empty star icon Empty star icon 2
I have made it halfway through this book and only because I worked through a much better book before I read this one.Android Studio Development Essentials by Neil Smyth is an example of a GOOD Android Studio Tutorial.Android Development with Kotlin by Marcin Moskala is an example of a BAD Android Studio Tutorial.When I see a code example " println(Text) " I know the author is not using Android Studio.When I see Github listing just code snippets instead of working examples I know the author is not using Android Studio.When I see Github code organized in Chapters and no Chapter numbers in the downloaded book I know the editor did not read all of the content.I can work around the broken english in this book and I really want to learn Kotlin on Android Studio, I guess the only way I will is when Neil Smyth writes a Kotlin version of his Android Studio Development Essentials.
Amazon Verified review Amazon
Ollie C Sep 25, 2017
Full star icon Full star icon Empty star icon Empty star icon Empty star icon 2
The breadth of coverage and touching on Android are valuable and the authors clearly have a great deal of knowledge about Kotlin but the book is severely let down by typos, poor grammar, code sample errors (one defines a class called Snail but instantiates one called Sneil!), duplicated text, images that are unreadable on a Kindle and poor English which is distracting (it's instead of its, sentences missing definite/indefinite articles, missing words, capital letters in the middle of sentences, etc). It's not an exaggeration to say most pages have errors on them, making it incredibly difficult to read and very poor value for money. Even one of the book's chapter *titles* has a glaring typo in it ("View binging" instead of "View binding"!). It's clear this book was not even looked at by a technical book editor. Packt told me they are now editing the book, but why didn't they do this before publishing it? Come on! Although the book does contain some Android examples there are very few. Kotlin in Action is a significantly higher quality book, in which I saw not a single copy error. It also contains Android examples and so I heartily recommend that as an alternative.
Amazon Verified review Amazon
Xolix Sep 14, 2019
Full star icon Empty star icon Empty star icon Empty star icon Empty star icon 1
This is probably the worst book for anyone starting out with Android development and Kotlin. The book is essentially a long list of loosely related details that might come up when working in Kotlin. Maybe there could have been a place for it as reference, but then of course it is already outdated. The one and only project - if one wants to call it that - starts on page 338 and assumes that one has read through the encyclopedic style of some hundred mini-topics. At that pint one then gets to type in reams of xml as the books doesn’t get into layout or other Android Studio related issues and any explanations from this point on are extremely brief or non-existing. Just thoughtless and horrible.
Amazon Verified review Amazon

People who bought this also bought

Left arrow icon
Test-Driven iOS Development with Swift
Test-Driven iOS Development with Swift
Read more
Apr 2022 280 pages
Full star icon 5 (3)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $33.99
$9.99 $26.99
$33.99
iOS 16 Programming for Beginners
iOS 16 Programming for Beginners
Read more
Nov 2022 686 pages
Full star icon 4.7 (50)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $44.99
$9.99 $35.99
$44.99
Machine Learning Techniques for Text
Machine Learning Techniques for Text
Read more
Oct 2022 448 pages
Full star icon 4.8 (6)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $46.99
$9.99 $37.99
$46.99
Apps and Services with .NET 8
Apps and Services with .NET 8
Read more
Dec 2023 798 pages
Full star icon 4.8 (22)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $49.99
$9.99 $39.99
$49.99
Apps and Services with .NET 7
Apps and Services with .NET 7
Read more
Nov 2022 814 pages
Full star icon 4.8 (27)
eBook
eBook
  • eBook eBook $9.99
  • Paperback Paperback $49.99
$9.99 $39.99
$49.99
Right arrow icon

About the authors

Left arrow icon
Profile icon Marcin Moskala
Marcin Moskala
Marcin Moskala is an experienced Android developer who is always looking for ways to improve. He has been passionate about Kotlin since its early beta release. He writes articles for Trade press and speaks at programming conferences. Marcin is quite active in the programming and open source community and is also passionate about cognitive and data science. You can visit his website, or follow him on GitHub (MarcinMoskala) and on Twitter (@marcinmoskala).
Read more
See other products by Marcin Moskala
Profile icon Igor Wojda
Igor Wojda
Igor Wojda is an experienced engineer with over 11 years of experience in software development. His adventure with Android started a few years ago, and he is currently working as a senior Android developer in the healthcare industry. Igor has been deeply interested in Kotlin development long before the 1.0 version was officially released, and he is an active member of the Kotlin community. He enjoys sharing his passion for coding with developers. To learn more about him, you can visit on Medium (@igorwojda) and follow him on Twitter (@igorwojda).
Read more
See other products by Igor Wojda
Right arrow icon
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