Book Image

Android Studio 3.5 Development Essentials - Kotlin Edition

By : Neil Smyth
Book Image

Android Studio 3.5 Development Essentials - Kotlin Edition

By: Neil Smyth

Overview of this book

Popularity of Kotlin as an Android-compatible language keeps growing every day. This book will help you to build your own Android applications using Kotlin. Android Studio 3.5 Development Essentials Kotlin Edition first teaches you to install Android development and test environment on different operating systems. Next, you will create an Android app and a virtual device in Android studio, and install an Android application on emulators. You will test apps on physical android devices, then study Android Studio code editor, Android architecture, and the anatomy of an Android app. The focus then shifts to Kotlin language. You’ll get an overview of Kotlin language and practice converting code from Java to Kotlin. You’ll also explore Kotlin data types, operators, expressions, loops, functions, and the basics of OOP concept in Kotlin. This book will then cover Android Jetpack and how to create an example app project using ViewModel component, as well as advanced topics such as views and widgets implementation, multi-window support integration, and biometric authentication. Finally, you will learn to upload your app to the Google Play Console and handle the build process with Gradle. By the end of this book, you will have gained enough knowledge to develop powerful Android applications using Kotlin.
Table of Contents (93 chapters)
93
Index

15.7 Declaring Default Function Parameters

Kotlin provides the ability to designate a default parameter value to be used in the event that the value is not provided as an argument when the function is called. This simply involves assigning the default value to the parameter when the function is declared.

To see default parameters in action the buildMessageFor function will be modified so that the string “Customer” is used as a default in the event that a customer name is not passed through as an argument. Similarly, the count parameter is declared with a default value of 0:

fun buildMessageFor(name: String = "Customer", count: Int = 0): String {

       return("$name, you are customer number $count")

}

When parameter names are used when making the function call, any parameters for which defaults have been specified may be omitted. The following function call, for example, omits the customer name argument...