I have created an android application which works properly for nexus 7.
Inside resources folder, I have created two folders, layout, layout-land for Ne
According to the Supporting Multiple Screens
Qualifiers like small, normal, large and xlarge is for Screen Sizes, which means Nexus 7 will use the resources with large qualifier, if you provide. Therefore before you create the folder with large qualifier, Nexus 7 will load the resources from default layout folder. As for ldpi, mdpi, hdpi and xhdpi is for the screen density.
To solve your problem, you need:
put the layout definitions for Galaxy S3 into layout, and layout-sw600dp for Nexus 7. Please refer to Android Developers Blog: Getting Your App Ready for Jelly Bean and Nexus 7
put the resources (images or drawable stuff) for Galaxy S3 into drawable-xhdpi, and drawable-tvdpi or drawable-hdpi for Nexus 7.
Hope it could help you, and please let me know if you have any other problems :)
Here are some useful references:
What layout is suitable for 720x1280 Android devices?
Screen Width Qualifier