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

RecyclerView and RecyclerAdapter


In Chapter 5, Beautiful Layouts with CardView and ScrollView, we used ScrollView and we populated it with a few CardView widgets so we could see it scrolling. We could take what we have just learned about arrays and ArrayList and create an array of TextViews, use them to populate ScrollView, and, within each TextView, place the title of a note. This sounds like a perfect solution for showing each note so that it is clickable in the Note to Self app.

We could create the TextViews dynamically in Java code, set their text property to be the title of a note, and then add the TextViews to a LinearLayout contained in a ScrollView. But this is imperfect.

The problem with displaying lots of widgets

This might seem fine, but what if there were dozens, hundreds, or even thousands of notes? We couldn't have thousands of TextViews in memory because the Android device might simply run out of memory, or at the very least grind to a halt, as it tries to handle the scrolling...