Book Image

How to Build Android Apps with Kotlin - Second Edition

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

How to Build Android Apps with Kotlin - Second Edition

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

The fragment lifecycle

A fragment is a component with its own lifecycle. Understanding the fragment lifecycle is critical as it provides callbacks at certain stages of fragment creation, the running state, and destruction that configure the initialization, display, and cleanup. Fragments run in an activity, and a fragment’s lifecycle is bound to the activity’s lifecycle.

In many ways, the fragment lifecycle is very similar to the activity lifecycle, and at first glance, it appears that the former replicates the latter. There are as many callbacks that are the same or similar in the fragment lifecycle as there are in the activity lifecycle, such as onCreate(savedInstanceState: Bundle?).

The fragment lifecycle is tied to the activity lifecycle, so wherever fragments are used, the fragment callbacks are interleaved with the activity callbacks.

The same steps are gone through to initialize the fragment and prepare for it to be displayed to the user before being available...