Book Image

Asynchronous Android

By : Steve Liles
Book Image

Asynchronous Android

By: Steve Liles

Overview of this book

With more than a million apps available from Google Play, it is more important than ever to build apps that stand out from the crowd. To be successful, apps must react quickly to user input, deliver results in a flash, and sync data in the background. The key to this is understanding the right way to implement asynchronous operations that work with the platform, instead of against it. Asynchronous Android is a practical book that guides you through the concurrency constructs provided by the Android platform, illustrating the applications, benefits, and pitfalls of each.Learn to use AsyncTask correctly to perform operations in the background, keeping user-interfaces running smoothly while avoiding treacherous memory leaks. Discover Handler, HandlerThread and Looper, the related and fundamental building blocks of asynchronous programming in Android. Escape from the constraints of the Activity lifecycle to load and cache data efficiently across your entire application with the Loader framework. Keep your data fresh with scheduled tasks, and understand how Services let your application continue to run in the background, even when the user is busy with something else.Asynchronous Android will help you to build well-behaved apps with smooth, responsive user-interfaces that delight users with speedy results and data that's always fresh, and keep the system happy and the battery charged by playing by the rules.
Table of Contents (14 chapters)
Asynchronous Android
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Scheduling alarms with AlarmManager


In Chapter 3, Distributing Work with Handler and HandlerThread, we learned to schedule work on a HandlerThread using postDelayed, postAtTime, sendMessageDelayed, and sendMessageAtTime. These mechanisms are fine for short-term scheduling of work that should happen soon—while our application is running in the foreground.

However, if we want to schedule an operation to run at some point in the distant future, we'll run into problems. First, our application may be terminated before that time arrives, removing any chance of the Handler running those scheduled operations. Second, the device may be asleep, and with its CPU powered down, it cannot run our scheduled tasks.

The solution to this is to use an alternative scheduling approach—one that is designed to overcome these problems: AlarmManager.

AlarmManager is a system service that provides scheduling capabilities far beyond those of Handler. Being a system service, AlarmManager cannot be terminated and has...