Added in API level 3

android.appwidget

Contains the components necessary to create "app widgets", which users can embed in other applications (such as the home screen) to quickly access application data and services without launching a new activity.

For more information, see the App Widgets guide.

The behavior of an app widget is published by an "app widget provider." An "app widget host" is a component that can contain app widgets (such as the Home screen).

Any application can publish app widgets (as an app widget provider). All an application needs to do to publish an app widget is provide a BroadcastReceiver that receives the ACTION_APPWIDGET_UPDATE intent and provide some metadata about the app widget. Android provides the AppWidgetProvider class, which extends BroadcastReceiver, as a convenience class to define the app widget behavior and aid in handling the broadcasts.

App widget hosts are the containers in which widgets can be placed. Most of the look and feel details are left up to the widget hosts. For example, the home screen has one way of viewing widgets, but the lock screen could also contain widgets, and it would have a different way of adding, removing and otherwise managing widgets.

For information about implementing an app widget host, see the AppWidgetHost class.

Classes

AppWidgetHost AppWidgetHost provides the interaction with the AppWidget service for apps, like the home screen, that want to embed AppWidgets in their UI. 
AppWidgetHostView Provides the glue to show AppWidget views. 
AppWidgetManager Updates AppWidget state; gets information about installed AppWidget providers and other AppWidget related state. 
AppWidgetProvider A convenience class to aid in implementing an AppWidget provider. 
AppWidgetProviderInfo Describes the meta data for an installed AppWidget provider.