Q:

Select layout xml files most appropriate, depending on screen size

I would like to know if You Could select a layaout xml Differently Depending on the size of the phone screen.
I try to  be more clear, I make more layout xml file, and I would like my app handles this statement 
setContentView (R.layout.main) 

first verifying on that size of the display is performed, and Therefore You Set the most appropriate layout xml

A:

What you could actually do is the following:
Create a new folder for each desired configuration and name that folder with qualifiers.
If you want your application to have a different main.xml layout for different screen sizes you should make the following folders in your project.
/res/layout-small
/res/layout-normal
/res/layout-large
/res/layout-xlarge

In each of those folders have your different main.xml file layout (or whatever resource you want). Android will pick the one it matches with the device is running your application.
You can even add different resources for different configurations for drawables and even for language.
More info: http://developer.android.com/guide/topics/resources/providing-resources.html

