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

Building an image gallery/slider app


Create a new project in Android Studio called Image Pager. Use the Empty Activity template and leave the remainder of the settings at their defaults.

These images are located in the download bundle in the Chapter25/Image Pager/drawable folder. The following diagram shows them in Windows Explorer:

Add the images to the drawable folder in the project explorer or, of course, you could add more interesting images, perhaps some photos you have taken.

Implementing the layout

For a simple image paging app, we use the PagerAdapter class. We can think of this as being like RecyclerApater but for images, as it will handle the display of an array of images in a ViewPager widget. This is much like RecyclerAdapter, which handles the display of the content of an ArrayList in a RecyclerView. All we need to do is override the appropriate functions.

To implement an image gallery with PagerAdapter, we first need a ViewPager widget in our main layout. So, you can see precisely...