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

Swiping to Remove Items

In the previous sections, we learned how to present different view types. However, up until now, we have worked with a fixed list of items. What if you want to be able to remove items from the list? There are a few common mechanisms to achieve that—fixed delete buttons, swipe to delete, and long-click to select then a "click to delete" button, to name a few. In this section, we will focus on the "swipe to delete" approach.

Let's start by adding the deletion functionality to our adapter. To tell the adapter to remove an item, we need to indicate which item we want to remove. The simplest way to achieve this is by providing the position of the item. In our implementation, this will directly correlate to the position of the item in our listData list. So, our removeItem(Int) function should look like this:

fun removeItem(position: Int) {
    listData.removeAt(position)
 ...