This is something from the APress site that would be of some help... Damon or Sebastien could throw more light on the content.
What you’ll learn
What Android web apps can do, and when to use web development rather than native development to create an application.
When to use HTML5 and when to use a native bridging framework to access native Android functionality.
Connext with cloud services and APIs to build engaging location based services and games.
Enable social integration with your Android web app and gain access to millions of potential users.
Gingerbread mostly adds new UI metaphors and performance improvements. In some cases, such as with the use of sensors and media, there are several new features in Gingerbread. For example Gingerbread now allows you to support multiple cameras, video chat would be one use case, were previous versions did not. They have also made the complete transition to a new media player and we document these changes.
As for Flex, HTML 5, etc we do not specifically cover Flex but Adobe has some great articles on working with AIR, HTML, and Flex on Android. As for HTML 5 Frank wrote a great chapter on build web applications in the book. I hope that helps.