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 the lateinit modifier


Lateinit is an important initialization property, because if you don't want to initialize your variable in constructor, lazy and lateinit can be employed to do so. In this recipe, we will see how to use the lateinit modifier and how it is different from the lazy modifier.

Getting ready

I'll be using IntelliJ IDEA for the coding purpose; you can use any IDE that can execute Kotlin code.

How to do it…

Let's follow the given steps to understand how the lateinit modifier works:

  1. In Java, we could just declare a variable beforehand and initialize it later, but Kotlin requires you to initialize it as soon as you declare it (unless you are using special modifiers). So you can do the following:
var student:Student?=null

Alternatively, you can do this:

val student=Student()

Both ways have their drawbacks. The first way will require you to check nullability whenever you use it, and the second way of initializing will make it immutable.

  1. To overcome limitations, we can use a lateinit...