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

Staying awake with WakeLocks


Earlier in this chapter we learned that we can use a BroadcastReceiver to handle alarms, and even do work in the background for up to 10 seconds, though only on devices running API level 11 or greater.

In the previous section, we saw that handling alarms directly with services is not a reliable solution for scheduling long-running work, since there is no guarantee that our Service will start up before the device returns to sleep.

We have a problem! If we want to perform long-running work in response to alarms, we need a solution that overcomes these limitations.

What we really want is to start a Service to handle the work in the background, and to keep the device awake until the Service has finished its work. Fortunately, we can do that by combining the wakefulness guarantees of BroadcastReceiver to get the Service started, then keep the device awake with explicit power management using PowerManager and WakeLock.

As you might guess, WakeLock is a way to force the...