Book Image

Android Studio 4.0 Development Essentials - Kotlin Edition

By : Neil Smyth
Book Image

Android Studio 4.0 Development Essentials - Kotlin Edition

By: Neil Smyth

Overview of this book

Kotlin as an Android-compatible programming language is becoming increasingly popular. Fully updated for Android Studio 4.0, this book will teach you the skills necessary to develop Android-based applications using Kotlin. Starting with the basics, this book outlines the steps necessary to set up Android development and testing environments, and goes on to introduce you to programming in Kotlin. You’ll practice Java to Kotlin code conversion and explore data types, operators, expressions, loops, functions, as well as the basics of OOP in Kotlin. You’ll then learn about Android architecture components and advanced topics, such as intents, touchscreen handling, gesture recognition, multi-window support integration, and biometric authentication. As you make progress, you’ll explore Android Studio 4.0’s key features, including layout editor, direct reply notifications, and dynamic delivery. You’ll also delve into Android Jetpack and create a sample app project using ViewModel, the Android Jetpack component. Finally, you will upload your app to Google Play Console and model the build process using Gradle. By the end of this Android book, you’ll be fully prepared to develop applications using Android Studio 4.0 and Kotlin.
Table of Contents (97 chapters)
97
Index

15.2 How to Declare a Kotlin Function

A Kotlin function is declared using the following syntax:

fun <function name> (<para name>: <para type>, <para name>: <para type>, ... ): <return type> {

         // Function code

}

This combination of function name, parameters and return type are referred to as the function signature or type. Explanations of the various fields of the function declaration are as follows:

fun – The prefix keyword used to notify the Kotlin compiler that this is a function.

<function name> - The name assigned to the function. This is the name by which the function will be referenced when it is called from within the application code.

<para name> - The name by which the parameter is to be referenced in the function code.

<para type> - The type of the corresponding parameter.

<return type&gt...