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

ANR and delays in software


ANR stands for Application Not Responding, and is one of the several nightmares of an Android developer. The Android operating system analyzes the status of apps and threads, and when certain conditions are met it triggers an ANR dialog, blocking the user from any interactive experience. The dialog announces that the application stopped responding, and is not responsive anymore. The user can select whether he/she wants to close the application, or keep waiting until the application becomes responsive again (if this ever happens):

What triggers ANRs and how can I avoid them?

Android systems trigger ANRs in two different situations:

  • When there has been no response for an event in five seconds

  • If a BroadcastReceiver is still executing 10 seconds after its execution

This happens mostly when an operation is being executed in the UI Thread. In general, any operation expected to be time- or operation-consuming should be performed in a separate thread, keeping the UI Thread available for the user interaction, and only notifying the UI Thread when the operation has been finished. In Chapter 5, Multithreading, we will show some advanced techniques for multithreading and thread communication. There are also different classes that can be used to perform operations in different threads, each of them with its own advantages and disadvantages. In general, when developing an application, remember: ANR dialog appearance frequency is inversely proportional to user satisfaction.