If set, specifies that this TextView has a numeric input method and that these specific characters are the ones that it will accept. If this is set, numeric is implied to be true. The default is false.

Must be a string value, using '\\;' to escape characters such as '\\n' or '\\uxxxx' for a unicode character.

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

[Android Documentation]