dp: Density-independent Pixels - an abstract
unit that is based on the physical density of the screen. These
units are relative to a 160 dpi (dots per inch) screen, so 160dp is
always one inch regardless of the screen density. The ratio of
dp-to-pixel will change with the screen density, but not
necessarily in direct proportion. You should use these units when
specifying view dimensions in your layout, so the UI properly
scales to render at the same actual size on different screens. (The
compiler accepts both "dip" and "dp", though "dp" is more
consistent with "sp".)
sp: Scale-independent Pixels - this is like the
dp unit, but it is also scaled by the user's font size preference.
It is recommend you use this unit when specifying font sizes, so
they will be adjusted for both the screen density and the user's
pt: Points - 1/72 of an inch based on the
physical size of the screen.
px: Pixels - corresponds to actual pixels on
the screen. This unit of measure is not recommended because the
actual representation can vary across devices; each devices may
have a different number of pixels per inch and may have more or
fewer total pixels available on the screen.
mm: Millimeters - based on the physical size of
in: Inches - based on the physical size of the