Book Image

Android Development with Kotlin

By : Igor Wojda, Marcin Moskala
Book Image

Android Development with Kotlin

By: Igor Wojda, Marcin Moskala

Overview of this book

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.
Table of Contents (16 chapters)
Title Page
About the Authors
About the Reviewers
Customer Feedback
Making Your Marvel Gallery Application


Classes are a fundamental building block of OOP. In fact, Kotlin classes are very similar to Java classes. Kotlin, however, allows more functionality together with simpler and much more concise syntax.

Class declaration

Classes in Kotlin are defined using the class keyword. The following is the simplest class declaration--an empty class named Person:

    class Person 

The definition of Person does not contain any body. Still, it can be instantiated using a default constructor:

    val person = Person() 

Even such a simple task as class instantiation is simplified in Kotlin. Unlike Java, Kotlin does not require the new keyword to create a class instance. Due to strong Kotlin interoperability with Java, we can instantiate classes defined in Java and Kotlin exactly the same way (without the new keyword). The syntax used to instantiate a class depends on the actual language used to create class instance (Kotlin or Java), not the language the class was declared in:

    // Instantiate Kotlin...