Android Screen Size

I got to know that the devices with screen resolution 1280x720 or 720x1280 are extra large screen devices.

But when I run my application on Samsung Galaxy S3 SGH-T999 (resolution 720x1280) throught eclipse, the following code prints "Normal screen" i.e. it is a normal screen device but according to my knowledge it should print "Extra Large screen". If its a normal screen size device actually then why its picking the layout (XML) file from res/layout-xlarge-port folder instead of res/layout? Need to understand this screen size concept so that I can make my application for multiple screen sizes.

// get and check the screen size of the device
int screenSize = getResources().getConfiguration().screenLayout &
Configuration.SCREENLAYOUT_SIZE_MASK;
switch(screenSize) {
case Configuration.SCREENLAYOUT_SIZE_XLARGE:
Toast.makeText(this, "Extra Large screen",Toast.LENGTH_LONG).show();
break;
[code]...