Book Image

Hands-On Android UI Development

By : Jason Morris
Book Image

Hands-On Android UI Development

By: Jason Morris

Overview of this book

A great user interface (UI) can spell the difference between success and failure for any new application. This book will show you not just how to code great UIs, but how to design them as well. It will take novice Android developers on a journey, showing them how to leverage the Android platform to produce stunning Android applications. Begin with the basics of creating Android applications and then move on to topics such as screen and layout design. Next, learn about techniques that will help improve performance for your application. Also, explore how to create reactive applications that are fast, animated, and guide the user toward their goals with minimal distraction. Understand Android architecture components and learn how to build your application to automatically respond to changes made by the user. Great platforms are not always enough, so this book also focuses on creating custom components, layout managers, and 2D graphics. Also, explore many tips and best practices to ease your UI development process. By the end, you'll be able to design and build not only amazing UIs, but also systems that provide the best possible user experience.
Table of Contents (21 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
13
Activity Lifecycle

Creating layouts for ViewHolders


A RecyclerView does just what its name suggests--it recycles or reuses its children to present different data to the user. This means that while it appears to have a long list of child-widgets (such as cards or images), it actually has the ones that the user can actually see. When a widget is scrolled off the screen, the RecyclerView changes its data, and then scrolls it back into view. The RecyclerView doesn't directly bind the data to the child views; however, it instead goes through a ViewHolder. The job of the ViewHolder is to help speed up the data binding process. Think of the travel claim app again; if we want to display each claim item in a RecyclerView, each one will look something like the following:

Each of the preceding items will require a different Android widget, and every time you want to populate them, they need to be looked up and bound to their new data. A ViewHolder implementation is a convenient place to look up, hold, and bind data for...