Widgets & BroadcastReceivers

One of the biggest things in all of mobile right now is the ability to have information available at a glance. These "at-a-glance" experiences are being highlighted in everything from Google Glass and Android Wear to the Apple Watch. In the latest version of Android, Google even introduced new pop-up style notifications to allow you access to important information even when you're in an immersive application.

While it might seem like the new hot topic in mobile, "at-a-glance" experiences have always been a part of Android through the use of home screen widgets. Home screen widgets allow developers to take the parts of their app that are rich in information and functionality, and bubble that information up into a micro-view that can exist directly on the Android home screen.

In this chapter, we'll be covering what these home screen widgets are used for, the different types of widgets, and how to build them. On the back-end, we'll also be covering the BroadcastReceiver class and how it can be used to send messages between application components and update your home screen widgets.