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

The life and times of an Android app


We have talked a bit about the structure of our code; we know that we can write classes, and within those classes we have functions, and these functions contain our code, which gets things done. We also know that when we want the code within a function to run (that is, be executed), we call that function by using its name.

Additionally, in Chapter 2, Kotlin, XML, and the UI Designer, we learned that Android itself calls the onCreate function just before the app is ready to start. We saw this when we output to the logcat window and used the Toast class to send a pop-up message to the user.

In this chapter, we will examine what happens throughout the lifecycle of every app that we write; that is, when it starts, ends, and the stages in between. What we will see is that Android interacts with our app on numerous occasions each time that it is run.

How Android interacts with our apps

Android interacts with our apps by calling functions that are contained within...