Book Image

Kotlin Programming Cookbook

By : Aanand Shekhar Roy, Rashi Karanpuria
Book Image

Kotlin Programming Cookbook

By: Aanand Shekhar Roy, Rashi Karanpuria

Overview of this book

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.
Table of Contents (21 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Using extensions as properties


In the last recipe, we learned about extension functions. In this recipe, we will learn about extension properties. If you feel the need for one or more properties from the class, you can add them using the extension properties. In this recipe, we will learn how to use extension properties.

Getting ready

I'll be using Android Studio for coding purposes. Ensure that you have the latest version of Android Studio with Kotlin configured.

How to do it…

Let's see an example of an extension property now:

  1. We will be using the example of shared preferences. You might be used to doing something like this to get hold of shared preferences:
PreferenceManager.getDefaultSharedPreferences(this)
  1. You can create an extension property on the Context class with name preferences and access it as follows:
valContext.preferences: SharedPreferences
       get() = PreferenceManager
       .getDefaultSharedPreferences(this)
context.preferences.getInt("...")

How it works…

The extension functions...