Book Image

Kotlin Blueprints

By : Ashish Belagali, Akshay Chordiya, Hardik Trivedi
Book Image

Kotlin Blueprints

By: Ashish Belagali, Akshay Chordiya, Hardik Trivedi

Overview of this book

Kotlin is a powerful language that has applications in a wide variety of fields. It is a concise, safe, interoperable, and tool-friendly language. The Android team has also announced first-class support for Kotlin, which is an added boost to the language. Kotlin’s growth is fueled through carefully designed business and technology benefits. The collection of projects demonstrates the versatility of the language and enables you to build standalone applications on your own. You’ll build comprehensive applications using the various features of Kotlin. Scale, performance, and high availability lie at the heart of the projects, and the lessons learned throughout this book. You’ll learn how to build a social media aggregator app that will help you efficiently track various feeds, develop a geospatial webservice with Kotlin and Spring Boot, build responsive web applications with Kotlin, build a REST API for a news feed reader, and build a server-side chat application with Kotlin. It also covers the various libraries and frameworks used in the projects. Through the course of building applications, you’ll not only get to grips with the various features of Kotlin, but you’ll also discover how to design and prototype professional-grade applications.
Table of Contents (16 chapters)
Title Page
About the Authors
About the Reviewer
Customer Feedback

Creating a social media aggregator

You will build an app that may look like the following:

UI representation of social media aggregator

And an application directory that will look like the following:

 Application directory

Using datatypes and conversion

In Kotlin, everything is an object. Kotlin has pretty much the same number of related data types compared to Java. But they are not exactly the same.

In Java, the following is true:

    int num=10;
    double bigNum=num;

But in Kotlin if you try to do such a thing it will give a compile-time error. This means implicit widening is not allowed in Kotlin. However, the main thing we want to discuss in this section is, with every number type Kotlin supports some explicit conversion and that can fill the gap of not having an implicit widening feature. Also, we often use utility methods from Java wrapper classes such as Integer.parseInt(), Float.valueOf(), and so on.

Every number type supports the following conversions: