Book Image

How to Build Android Apps with Kotlin - Second Edition

By : Alex Forrester, Eran Boudjnah, Alexandru Dumbravan, Jomar Tigcal
5 (1)
Book Image

How to Build Android Apps with Kotlin - Second Edition

5 (1)
By: Alex Forrester, Eran Boudjnah, Alexandru Dumbravan, Jomar Tigcal

Overview of this book

Looking to kick-start your app development journey with Android 13, but don’t know where to start? How to Build Android Apps with Kotlin is a comprehensive guide that will help jump-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 with 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. You'll also get to grips with testing, learning how to keep your architecture clean, understanding how to persist data, and gaining 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 (24 chapters)
1
Part 1: Android Foundation
6
Part 2: Displaying Network Calls
12
Part 3: Testing and Code Structure
17
Part 4: Polishing and Publishing an App

Parsing a JSON response

Now that we have successfully retrieved a JSON response from an API, it is time to learn how to use the data we have obtained. To do so, we need to parse the JSON payload. This is because the payload is a plain string representing the data object, and we are interested in the specific properties of that object. If you look closely at Figure 5.2, you may notice that the JSON contains breed information, an image URL, and some other bits of information. However, for our code to use that information, first, we must extract it.

As mentioned in the introduction, multiple libraries exist that will parse a JSON payload for us. The most popular ones are Google’s GSON (see https://github.com/google/gson) and, more recently, Square’s Moshi (see https://github.com/square/moshi). Moshi is very lightweight, which is why we have chosen to use it in this chapter.

What do JSON libraries do? Basically, they help us convert data classes into JSON strings ...