Up to this point we've been working with the standard Android themes and styling. From a consistency point of view, this is a very good thing, since the application will blend properly with the device's theming (if it has any). However, there are times when you need to be able to define your own styling. This styling may only apply to a single widget, or it may apply to the entire application. In any of these cases, you'll need to know what tools you have available from Android in order to decide how best to approach the problem at hand.
There is more to styling than just making your application look good. Also, what you think would look good, another person may hate. It's also about making the application more useful to your users. This may involve making sure that your application looks right no matter which language the user chooses. It may involve additional colors for some chosen widgets, or it may simply involve implementing a landscape layout...