sorry for the late answer.
Dynamically (on RunTime) probably not, because Resources-Files get compiled into your application and on compile-time the screen-resolutions of the device your application will run on is unknown.
You work XML-Layouts, because
you want to be resolution-independent
(Working with FILL_PARENT and WRAP_CONTENT is probably not what you are looking for
To make it easier to change you could define Dimension-Resources:
Source file format: XML file requiring a <?xml version="1.0" encoding="utf-8"?> declaration, and a root <resources> element containing one or more <dimen> tags.
Implementation like this:
Using xml Syntax Highlighting
<?xml version="1.0" encoding="utf-8"?>
Parsed in 0.002 seconds, using GeSHi
Hope I could help you.