Number distance(Location loc1, Location loc2)

[Bushmills]

Will calculation consider Earth a perfect sphere, or take into account equator bulging and pole flattening?

[Martin]

Android documents it like this:

Returns the approximate distance in meters between this location and the given location. Distance is defined using the WGS84 ellipsoid.

The source contains a reference to this PDF: http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf