Declare that your application will be able to deal with RTL (right to left) layouts. If set to false (default value), your application will not care about RTL layouts.

Must be a boolean value, either "true" or "false".

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]