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)
Preface
12
12. Dependency Injection with Dagger and Koin

Responding to Clicks in RecyclerView

What if we want to let our users select an item from the presented list? To achieve that, we need to communicate clicks back to our app.

The first step in implementing click interaction is to capture clicks on items at the ViewHolder level.

To maintain separation between our view holder and the adapter, we define a nested OnClickListener interface in our view holder. We choose to define the interface within the view holder because they are tightly coupled. The interface will, in our case, have only one function. The purpose of this function is to inform the owner of the view holder about the clicks. The owner of a view holder is usually a Fragment or an Activity. Since we know that a view holder can be reused, we know that it can be challenging to define it at construction time in a way that would tell us which item was clicked (since that item will change over time with reuse). We work around that by passing the currently presented item back...