Question

Possible Duplicate:
What means Ems? (Android TextView)

In EditText there is an attribute named android:ems. The description
is “Makes the EditText be exactly this many ems wide”

What does ems mean?

Answer 1

Taken from: http://www.w3.org/Style/Examples/007/units:

The em is simply the font size. In an element with a 2in font, 1em
thus means 2in. Expressing sizes, such as margins and paddings, in em
means they are related to the font size, and if the user has a big
font (e.g., on a big screen) or a small font (e.g., on a handheld
device), the sizes will be in proportion. Declarations such as
‘text-indent: 1.5em’ and ‘margin: 1em’ are extremely common in CSS.

em is basically CSS property for font sizes.