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

Handling alarms


Now that we know how to schedule alarms, let's take a look at what we can schedule with them.

Essentially, we can schedule anything that can be started with a PendingIntent, which means we can use alarms to start Activities, Services, and BroadcastReceivers. To specify the target of our alarm, we need to use the static factory methods of PendingIntent:

PendingIntent.getActivities(…)
PendingIntent.getActivity(…)
PendingIntent.getService(…)
PendingIntent.getBroadcast(…)

In the following sections, we'll see how each type of PendingIntent can be used with AlarmManager.

Handling alarms with Activities

Starting an Activity from an alarm is as simple as registering the alarm with a PendingIntent created by invoking the static getActivity method of PendingIntent.

When the alarm is delivered, the Activity will be started and brought to the foreground, displacing any app that was currently in use. Keep in mind that this is likely to surprise and perhaps annoy users!

When starting Activities...