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

Initializing body of constructor


In the Java world, we used to initialize fields of the class in the constructor, as shown in this code:

class Student{
 int roll_number;
 String name;
 Student(int roll_number,String name){
     this.roll_number =roll_number;
     this.name = name;
 }
}

So, if the argument's name was similar to that of the property (which was usually the case for making the code more readable), we needed to use this keyword. In this recipe, we will see how to implement the same thing in Kotlin (obviously with much less code).

Getting ready

You need an IDE to write and execute your code. I'll be using IntelliJ IDEA. We will create a Student class with name and roll_number as properties.

How to do it...

Let's look at the mentioned steps to initialize a constructor:

  1. Kotlin provides a syntax that can initialize the properties with much less code. Here's what class initialization looks like in Kotlin:
class Student(var roll_number:Int, var name:String)
  1. You don't even need to define the...