Book Image

Android High Performance Programming

By : Emil Atanasov, Enrique López Mañas, Diego Grancini
Book Image

Android High Performance Programming

By: Emil Atanasov, Enrique López Mañas, Diego Grancini

Overview of this book

Performant applications are one of the key drivers of success in the mobile world. Users may abandon an app if it runs slowly. Learning how to build applications that balance speed and performance with functionality and UX can be a challenge; however, it's now more important than ever to get that balance right. Android High Performance will start you thinking about how to wring the most from any hardware your app is installed on, so you can increase your reach and engagement. The book begins by providing an introduction to state–of-the-art Android techniques and the importance of performance in an Android application. Then, we will explain the Android SDK tools regularly used to debug and profile Android applications. We will also learn about some advanced topics such as building layouts, multithreading, networking, and security. Battery life is one of the biggest bottlenecks in applications; and this book will show typical examples of code that exhausts battery life, how to prevent this, and how to measure battery consumption from an application in every kind of situation to ensure your apps don’t drain more than they should. This book explains techniques for building optimized and efficient systems that do not drain the battery, cause memory leaks, or slow down with time.
Table of Contents (17 chapters)
Android High Performance Programming
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Autopsy of an APK file


Let's suppose we have obtained an APK file. For the purpose of this section, and to keep the exercise easy, we will create a HelloWorld application, including merely a TextView inside Activity.

To proceed analyzing the interior of our application, let's first unzip the APK and check its content. We will see content similar to the following:

For the newbies in this world, we can see that the Android manifest and the resources inside the res folder are directly accessible. The file, classes.dex, includes the compiled Java files as we explained in the previous section. The file, Resources.arsc (Application Resource Files), contains a list of binary resources, including any kind of data used by the program. This file is created by the Android Asset Packaging Tool (aapt).

We will now introduce the first technique to read the code of a file that has not been obfuscated, and is transforming the file into a JAR file and then opening it with a decompiler. We will need two tools...