By Fuad Kamal - Saving Data on Android

By Jennifer Bailey, Dean Djermanovi, Aldo Olivares Dominguez,

Fuad Kamal,Subhrajyoti Sen & Harun Wangereka

By Jennifer Bailey, Dean Djermanovi, Aldo Olivares Dominguez, Fuad Kamal, Subhrajyoti Sen & Harun Wangereka

Copyright 2021 Razeware LLC.

All rights reserved. No part of this book or corresponding materials (such as text, images, or source code) may be reproduced or distributed by any means without prior written permission of the copyright owner.

This book and all corresponding materials (such as source code) are provided on an as is basis, without warranty of any kind, express of implied, including but not limited to the warranties of merchantability, fitness for a particular purpose, and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in action of contract, tort or otherwise, arising from, out of or in connection with the software or the use of other dealing in the software.

All trademarks and registered trademarks appearing in this book are the property of their own respective owners.

By purchasing Saving Data on Android, you have the following license:

• You are allowed to use and/or modify the source code in Saving Data on Android in as many apps as you want, with no attribution required.

• You are allowed to use and/or modify all art, images and designs that are included in Saving Data on Android in as many apps as you want, but must include this attribution line somewhere inside your app: Artwork/images/designs: from _Saving Data on Android, available at www.raywenderlich.com.

• The source code included in Saving Data on Android is for your personal use only. You are NOT allowed to distribute or sell the source code in Saving Data on Android without prior authorization.

• This book is for your personal use only. You are NOT allowed to sell this book without prior authorization, or distribute it to friends, coworkers or students; they would need to purchase their own copies.

All materials provided with this book are provided on an as is basis, without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the software or the use or other dealings in the software.

All trademarks and registered trademarks appearing in this guide are the properties of their respective owners.

This section tells you a few things you need to know before you get started, such as what youll need for hardware and software, where to find the project files for this book, and more.

To follow along with this book, you need:

• Android Studio 4.1+: Available at https://developer.android.com/studio/. This is the environment in which youll develop most of the sample code in this book. If you didn't install it already, now is the right time to do that!

• Java SE Development Kit 8+: Most of the code in this book will be run on the Java Virtual Machine or JVM, for which you need a Java Development Kit or JDK. The JDK can be downloaded from Oracle at http://www.oracle.com/technetwork/java/javase/downloads/index.html.

• Kotlin Playground: You can also use the Kotlin Playground available at the Kotlin home page at https://play.kotlinlang.org.

• Android 6.0+: The minimumSdkVersion for the projects targets API 23. Therefore, you need an emulator or device running API 23 or higher.

The materials for this book can be cloned or downloaded from the GitHub book materials repository:

• https://github.com/raywenderlich/sda-materials/tree/editions/2.0

Weve also set up an official forum for the book at https://forums.raywenderlich.com/c/books/saving-data-on-android. This is a great place to ask questions about the book or to submit any errors you may find.

Dragons are an extremely common and ancient piece of folklore in nearly all cultures around the world. Most dragons are thought to breathe fire, or even ice, but legend has it that green dragons breathe acid. Any warrior brave enough to charge a green dragon would have the story of her battle permanently etched on her armor and shield from the dragons acid.

Saving data on Android etches the story of data in a persistent manner on the users device. Theres hardly an app out there that doesnt persist data in some way. After reading Saving Data on Android, youll be armed and ready to charge fearlessly into battle with the dragons of development, to save your users data!

"In loving memory of my wife, Huma. Not every warrior carries a sword."

Fuad Kamal

"To my parents, friends and colleagues, who have always supported me and pushed me to achieve more. This book wouldn't have been possible without them."

Subhrajyoti Sen

"To my Mum for always supporting me. To my wife for the encouragement and amazing support in everything that I work on. To my extended family, friends and colleagues who always push me to be a better version of myself. And to Apps:Lab for nurturing and providing me the opportunity to better myself, as well as all the Android Bits members for the guidance throughout my journey as a developer."

Harun Wangereka

Fuad Kamal is one of the authors of this book. Fuad provides mobile strategy, architecture and development for the Health, Fitness and Telematics markets. If youve ever been to an airport, youve likely seen his work the flight arrival and departure screens are a Flash 7 interface he wrote near the beginning of the millennium. He's also into photography. He's https://twitter.com/FlexRonin on Twitter and Instagram or you can contact him through anaara.com.

Subhrajyoti Sen is one of the authors of this book. Subhrajyoti is a Google Developer Expert for Android and an Android Engineer at KeepTruckin, where he develops apps to improve the trucking industry. Before this, he also worked on apps to improve the experience of Indian investors. He believes in the power of Open Source and communities and actively tries to give back. When not writing code, you can find him binge-watching anime, reading up on public policy or playing Rocket League.