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

Making decisions in Kotlin


Our Kotlin code will constantly be making decisions. For example, we might need to know whether the user has new messages, or whether they have a certain number of friends. We need to be able to test our variables to see whether they meet certain conditions, and then execute a specific section of code depending upon whether they did or not.

In this section, as our code gets more in-depth, it helps to present the code in a way that makes it more readable. Let's take a look at code indenting to make our discussion about making decisions easier.

Indenting code for clarity

You have probably noticed that the Kotlin code in our project is indented. For example, the first line of code inside the MainActivity class is indented by one tab. Additionally, the first line of code is indented inside each function by another tab; here is an annotated diagram to make this clear:

Notice that when the indented block has ended, often with a closing curly brace (}), it is indented to...