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

Nothing return type

Sometimes we need to define a function that is always throwing exceptions (never terminating normally). Two real-life use cases are:

  • Functions that simplify error throwing. This is especially useful in libraries where the error system is important and there is a need to provide more data about error occurrences. (As an example, look at the throwError function presented in this section.)
  • Functions used for throwing errors in unit tests. This is useful when we need to test error handling in our code.

For these kinds of situation, there is a special class called Nothing. The Nothing class is an empty type (uninhabited type), meaning it has no instances. A function that has Nothing return type won't return anything and it will never reach the return statement. It can only throw an exception. This is why when we see that a function is returning Nothing, then it is designed to throw exceptions. This way we can distinguish functions that do not return a value (such as Java's void...