Android App Widget Design Guidelines

A widget displays an application's most important or timely information at a glance, on a user's Home screen. These design guidelines describe how to design widgets that fit with others on the Home screen. They include links to graphics files and templates that will make your designer's life easier.


Check the following Google link for Android application widget design guidelines.
http://developer.android.com/guide/practices/ui_guidelines/widget_design.html

Android Compatibility

If you're an organization building an Android device, you'll want to check out Google Compatibility pages to find out how to take advantage of the benefits of compatibility.

Get Compatible »

Source Code Available for Android 4.0

The source code for the Android 4.0 platform and software stack has been released!


This release allows OEMs to begin preparing Android 4.0 for installation on new and existing devices, and allows hobbyists, enthusiasts, and researchers to develop custom builds.


For information on how to obtain the software, visit our Getting the Source page. 

Android 4.1, Jelly Bean

Android 4.1, Jelly Bean, is the fastest and smoothest version of Android yet. Jelly Bean improves on the simplicity and beauty of Android 4.0, and introduces a new Google search experience on Android.

http://www.android.com/about/jelly-bean/