Book Image

How to Build Android Apps with Kotlin

By : Alex Forrester, Eran Boudjnah, Alexandru Dumbravan, Jomar Tigcal
Book Image

How to Build Android Apps with Kotlin

By: Alex Forrester, Eran Boudjnah, Alexandru Dumbravan, Jomar Tigcal

Overview of this book

Are you keen to get started building Android 11 apps, but don’t know where to start? How to Build Android Apps with Kotlin is a comprehensive guide that will help kick-start your Android development practice. This book starts with the fundamentals of app development, enabling you to utilize Android Studio and Kotlin to get started building Android projects. You'll learn how to create apps and run them on virtual devices through guided exercises. Progressing through the chapters, you'll delve into Android’s RecyclerView to make the most of lists, images, and maps, and see how to fetch data from a web service. Moving ahead, you'll get to grips with testing, learn how to keep your architecture clean, understand how to persist data, and gain basic knowledge of the dependency injection pattern. Finally, you'll see how to publish your apps on the Google Play store. You'll work on realistic projects that are split up into bitesize exercises and activities, allowing you to challenge yourself in an enjoyable and attainable way. You'll build apps to create quizzes, read news articles, check weather reports, store recipes, retrieve movie information, and remind you where you parked your car. By the end of this book, you'll have the skills and confidence to build your own creative Android applications using Kotlin.
Table of Contents (17 chapters)
12. Dependency Injection with Dagger and Koin

Loading Images from a Remote URL

We just learned how to extract particular data from an API response. Quite often, that data will include URLs to images we want to present to the user. There is quite a bit of work involved in achieving that. First, you have to fetch the image as a binary stream from the URL. Then, you need to transform that binary stream into an image (it could be a GIF, JPEG, or one of a few other image formats). Then, you need to convert it into a bitmap instance, potentially resizing it to use less memory.

You may also want to apply other transformations to it at that point. Then, you need to set it to an ImageView. Sounds like a lot of work, doesn't it? Well, luckily for us, there are a few libraries that do all of that (and more) for us. The most commonly used libraries are Square's Picasso ( and Glide by Bump Technologies ( Facebook's Fresco ( is somewhat...