Book Image

Android Programming for Beginners - Second Edition

By : John Horton
Book Image

Android Programming for Beginners - Second Edition

By: John Horton

Overview of this book

Are you trying to start a career in programming, but haven't found the right way in? Do you have a great idea for an app, but don't know how to make it a reality? Or maybe you're just frustrated that in order to learn Android, you must know Java. If so, then this book is for you. This new and expanded second edition of Android Programming for Beginners will be your companion to create Android Pie applications from scratch. We will introduce you to all the fundamental concepts of programming in an Android context, from the basics of Java to working with the Android API. All examples use the up-to-date API classes, and are created from within Android Studio, the official Android development environment that helps supercharge your application development process. After this crash course, we'll dive deeper into Android programming and you'll learn how to create applications with a professional-standard UI through fragments and store your user's data with SQLite. In addition, you'll see how to make your apps multilingual, draw to the screen with a finger, and work with graphics, sound, and animations too. By the end of this book, you'll be ready to start building your own custom applications in Android and Java.
Table of Contents (35 chapters)
Android Programming for Beginners - Second Edition
Contributors
Preface
Other Books You May Enjoy
Index

Persisting data with SharedPreferences


In Android, there are a few ways to make data persist. By persist, I mean that if the user quits the app, then when they come back to it, their data is still available. What method is the correct one to use is dependent upon the app and the type of data.

In this book, we will look at three ways to make data persist. For saving our user's settings, we only need a simple method. After all, we just need to know whether they want the decorative divider between each of the notes in the RecyclerView.

Let's look at how we can make our apps save and reload variables to the internal storage of the device. We need to use SharedPreferences objects. SharedPreferences is a class that provides access to data that can be accessed and edited by all Activity classes of an app. Let's look at how we can use it:

// A SharedPreferences for reading data
SharedPreferences prefs;

// A SharedPreferences.Editor for writing data
SharedPreferences.Editor editor;

As with all objects...