Kotlin Blueprints by Belagal, Ashish -- Read -- Imperial Library of Trantor

Index

Title Page Copyright

Kotlin Blueprints

Credits About the Authors Acknowledgments About the Reviewer www.PacktPub.com

Why subscribe?

Customer Feedback Preface

What this book covers What you need for this book Who this book is for Conventions Reader feedback Customer support

Downloading the example code Downloading the color images of this book Errata Piracy Questions

The Power of Kotlin

Kotlin – a better Java

Why not other languages? Why Kotlin?

Concise yet expressive code

Enhanced robustness

Excellent IDE support from day one

Beyond being a better Java

Kotlin is in the winning camp Go native strategy

Kotlin's winning strategy Summary

Geospatial Messenger – Spring Boot

Why Spring Boot?

Leveraging Kotlin in Spring Boot applications

Extension functions Constructor injection Leveraging Null safety Functional bean declaration DSL

Let's build our geospatial messenger

Preview Features

Architecture

Setting up the IDE

Creating a project Project structure

Setting up the build script

Adding Kotlin dependency Adding Spring Boot dependencies Exposed library

Gradle dependency Defining the table Connecting to the database CRUD operations

Explaining PostGIS

Installation Gradle dependency

Object mapping

Gradle dependency

Completing the Gradle script

Coding the application

Frontend

HTML CSS JavaScript

Rendering the map Plotting messages on the map Listening to message saved events Complete JavaScript

Application class

Backend

Application configuration Data classes Exposed integration

Exposed objects Extras for geospatial support

Service/Controller Repository CrudRepository Event broadcaster Extension functions

Testing

Gradle dependency Test cases

Pro-tips

All-open compiler plugin Spring starter Playing with the Java to Kotlin converter Migrating to Kotlin

Should I rewrite the existing Java code in Kotlin? What if I want to rewrite Java to Kotlin?

Summary

Social Media Aggregator Android App

Setting up Kotlin

Setting up the Kotlin plugin for Android Studio Getting started

Converting Java code to Kotlin code

Creating a social media aggregator

Using datatypes and conversion String interpolation

String utility methods

Classes

Constructors Data classes Inheritance Singletons

lateinit versus lazy initialization

lateinit The lazy property

Control flow

The when() expression

Getters and setters

Declaring a property

Interfaces Kotlin Android extension

Ditching the findViewById() method View extensions Fragment LayoutInflater extension The Standard.kt function

The with() function The apply() function The let() function

Functions in Kotlin

Single-expression function Inline function Default and named parameters

Default parameter Named parameter

Destructing declaration

Android context Null-Safety

Why Kotlin is called null-safe Safe call operator (?.) Elvis operator (?:) Force unwrap (!!)

Smart casts

The is and !is operators The as operator

Companion object

Fragment instantiation using companion objects

Dealing with constants Object expressions and declarations Delegated properties

Dealing with Shared Preferences

Setting up an item click on RecyclerView Anko - Kotlin's buddy for Android

Setting up Anko Displaying toast() Starting an activity made easy Anko layout

Summary

Weather App Using Kotlin for JavaScript

Creating your first Kotlin and JavaScript project

Choosing an IDE Creating a project Creating an HTML page Creating a Main.kt file Running the project

Developing a weather forecast web app

Creating a UI with dummy data

Simple HTML approach

Creating UI using Kotlin

What is DSL? Using Kotlinx.html

Refactoring the HTML code using DSL

Calling a weather API

Reading data from input elements Data classes

Showing data to the user Showing weather details

Named parameters Extension functions

Giving final touches

Adding CSS

Interoperability with JavaScript Summary

Chat Application with Server-Side JavaScript Generation

Creating our first Node.js app using Kotlin

Choosing an IDE Installing Node.js Installing the Node.js plugin Creating a project

Creating a chat application

Setting up the Node.js server Specifying the output files

Examining the compilation output

Specifying the router Starting the node server Creating a login page

Creating an index.ejs file Using DSL Using kotlinx.html

Lambda functions Reading the nickname Passing nickname to the server

Smart cast Registering a callback

Establishing a socket connection

Setting up Socket.IO Listening to events Emitting the event Incrementing and decrementing operator overloading

Showing a list of online users

Using the data class Using the Pair class Iterating list

Sending and receiving a message

Null safety Force unwraps Using the let function Named parameter

Disconnecting a socket Styling the page using CSS

Summary

News Feed – REST API

What is REST? What is Ktor?

Why Ktor?

Understanding unopinionated applications Asynchronous nature Highly testable

Deploying the Ktor app

Let's build our news application

News provider

Fetching news sources Fetching news articles

Preview Features Architecture Setting up the IDE

Prerequisites Creating the project Project structure Deploying

Deploying in IntelliJ IDEA

Setting up the build script

Adding Kotlin dependency Adding Ktor dependencies Configuring logging Adding Fuel

What is Fuel? Adding Gradle dependency Quick sample

Asynchronous mode Blocking mode

Completing Gradle script

Let's code!

Application configuration

Deployment block Application block

Application main

Installing routing

Simple routing Modular routing Understanding route paths Path parameters

Testing

Adding Gradle dependency Testing the application

Testing the index URL Testing JSON using Postman

Testing news sources using Postman Testing news sources using Postman

Summary

CSV Reader in Kotlin Native

What is Kotlin Native?

Target platforms Multiplatform Kotlin

Installing Kotlin Native

Installing from the source Installing from binaries Testing the installation Memory management

Building our app

Writing the main function Reading command-line arguments Opening the file Reading the file contents Counting unique entries

Converting to Kotlin string Splitting strings Printing the result

Complete code Running the program

Understanding the dataset Compiling the program Executing the program

Multiplatform Kotlin

Project structure

Common module Platform module Regular module Overview of the dependency structure

Setting up a multiplatform project

Creating a multiplatform project with an IDE Creating a multiplatform project without an IDE

Summary

Dictionary Desktop Application - TornadoFX

Introducing TornadoFX

Java-based desktop frameworks TornadoFX special additions

Creating a type-safe UI versus FXML Type-safe styling Other improvements

Let's build our dictionary application

What we will build Words API

Definition API

Features of our application Setting up the IDE

Prerequisites Installing the TornadoFX plugin Creating the project Project structure

Let's code!

Application class Type-safe CSS Dependency injection Property delegate Consuming the REST API

Defining the Model

Implementing the JSONModel interface

REST client

Configuring the client

Controllers

Views Layouts

VBox layout HBox layout Other layouts Forms

Background operations Printing the result Complete View

Launching the application Summary

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