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 Programming will make you think 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; 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.
This book explains techniques for building optimized and efficient systems that do not drain the battery, cause memory leaks, or slow down with time.
Chapter 1, Introduction: Why High Performance?, provides an introduction to the topic, the current state of the art in Android, and the importance of performance in an Android application.
Chapter 2, Efficient Debugging, covers the tools provided by the Android SDK (and some externals) that are regularly used to debug and profile Android applications.
Chapter 3, Building Layouts, will take you through the techniques used to optimize Android routines, write applications that use memory efficiently, and explain concepts from memory allocation to garbage collection.
Chapter 4, Memory, provides many insights to the UI design that need to be learnt in order to create an efficient UI that loads fast, without giving a lag perception to the user and that gets updated efficiently.
Chapter 5, Multithreading, explains all the different threading options in an Android application and when we should apply each. Some advanced techniques, such as IPC, will be also shown with practical code.
Chapter 6, Networking, shows techniques used to perform efficient network operations, and techniques to retrieve data from servers such as exponential back offs or avoiding polling.
Chapter 7, Security, covers techniques to secure an Android application, how to make use of the security encryption mechanisms provided by Android natively, and how to get information about connections or just be notified of connection changes.
Chapter 8, Optimizing Battery Consumption, provides typical examples of code that exhausts battery life, how to prevent it, and how to measure battery consumption from an application in every kind of situation; many developers don't know how to behave while developing apps to take a photo or a video, handling with previews, and saving data.
Chapter 9, Native Coding in Android, this chapter is a workaround in the world of native code and C++ in Android and its usage.
Chapter 10, Performance Tips, helps developer to be guided in common coding situations, where wrong choices can compromise app efficiency; this will be a best practice guide related to topics not dealt with in previous chapters.
You will need the following hardware for this book:
PC/laptop running Windows, Linux, or Mac OS X
Android phone. A high-end model is recommended, with at least Android 5.0 installed.
This topic is aimed at developers with advanced knowledge of Android, who want to push their knowledge and learn techniques to increase the performance of their applications. We assume they are comfortable working with the entire Android SDK, and have been doing it for years. They are familiar also with frameworks such as the NDK to use native code, which is crucial to performance.
In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "If you go to this folder and call the command adb, you will see on the screen a list of the available options."
A block of code is set as follows:
<resources>
<style name="Theme.NoBackground" parent="android:Theme">
<item name="android:windowBackground">@null</item>
</style>
</resources>Any command-line input or output is written as follows:
adb shell dumbsys gfxinfo <PACKAGE_NAME>
New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "To debug the overdraw on the device, Android provides a helpful tool that can be enabled inside the Developer options."
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