Book Image

Android Programming with Kotlin for Beginners

By : John Horton
5 (1)
Book Image

Android Programming with Kotlin for Beginners

5 (1)
By: John Horton

Overview of this book

Android is the most popular mobile operating system in the world and Kotlin has been declared by Google as a first-class programming language to build Android apps. With the imminent arrival of the most anticipated Android update, Android 10 (Q), this book gets you started building apps compatible with the latest version of Android. It adopts a project-style approach, where we focus on teaching the fundamentals of Android app development and the essentials of Kotlin by building three real-world apps and more than a dozen mini-apps. The book begins by giving you a strong grasp of how Kotlin and Android work together before gradually moving onto exploring the various Android APIs for building stunning apps for Android with ease. You will learn to make your apps more presentable using different layouts. You will dive deep into Kotlin programming concepts such as variables, functions, data structures, Object-Oriented code, and how to connect your Kotlin code to the UI. You will learn to add multilingual text so that your app is accessible to millions of more potential users. You will learn how animation, graphics, and sound effects work and are implemented in your Android app. By the end of the book, you will have sound knowledge about significant Kotlin programming concepts and start building your own fully featured Android apps.
Table of Contents (33 chapters)
Android Programming with Kotlin for Beginners
Contributors
Preface
Index

Introduction to references


There might be a nagging thought in your mind at this point. Look at the two functions from the Shipyard class again:

fun serviceDestroyer(destroyer: Destroyer){
        destroyer.serviceShip()
}

fun serviceCarrier(carrier: Carrier){
        carrier.serviceShip()
}

When we called those functions and passed the friendlyDestroyer and friendlyCarrier to their appropriate service… function, we saw, from the before and after output, that the values inside the instances were changed. Usually, if we want to keep the result from a function, we need to use the return value. What is happening is that, unlike a function that has regular types as parameters, when we pass an instance of a class, we are really passing a reference to the instance itself – not just copies of the values within it, but the actual instance.

Furthermore, all the different ship-related instances were declared with val, so how did we change any of the properties at all? The short answer to this conundrum...