Book Image

Android Application Development Cookbook - Second Edition

By : Kyle Mew
Book Image

Android Application Development Cookbook - Second Edition

By: Kyle Mew

Overview of this book

The Android OS has the largest installation base of any operating system in the world; there has never been a better time to learn Android development to write your own applications, or to make your own contributions to the open source community! This “cookbook” will make it easy for you to jump to a topic of interest and get what you need to implement the feature in your own application. If you are new to Android and learn best by “doing,” then this book will provide many topics of interest. Starting with the basics of Android development, we move on to more advanced concepts, and we’ll guide you through common tasks developers struggle to solve. The first few chapters cover the basics including Activities, Layouts, Widgets, and the Menu. From there, we cover fragments and data storage (including SQLite), device sensors, the camera, and GPS. Then we move on more advanced topics such as graphics and animation (including OpenGL), multi-threading with AsyncTask, and Internet functionality with Volley. We’ll also demonstrate Google Maps and Google Cloud Messaging (also known as Push Notifications) using the Google API Library. Finally, we’ll take a look at several online services designed especially for Android development. Take your application big-time with full Internet web services without having to become a server admin by leveraging the power of Backend as a Service (BaaS) providers.
Table of Contents (23 chapters)
Android Application Development Cookbook Second Edition
Credits
Disclaimer
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Optimizing layouts with the Hierarchy Viewer


Before you can start optimizing your layouts, it helps to understand the Android layout process. Inflating a layout, begins when the activity first comes into display. Three steps occur:

  • Measure: This is where the Views determine their size, starting with the parent and working through all the children. The parent may have to call its children multiple times to work out the final size.

  • Layout: This is where the parent determines the position of its children

  • Draw: This is where the Views are actually rendered

This process starts with the parent, which then iterates through all its children. Those children iterate through their children. This creates the Layout Tree, with the parent becoming the root node in the tree.

Hierarchy Viewer is a tool included with the Android SDK for inspecting layouts. It graphically shows the Layout Tree along with timing results for each view/node. By examining the tree layout and the timing; you can look for inefficient...