XML Fragments
An XML Fragment is a light-weight UI part (UI sub-tree) defined in XML that is similar to an XML view but has no <View> tag as its root element. Developers use XML Fragments to encapsulate and reuse portions of UI markup independently of any specific view, for example to define dialogs that can be shared across multiple views. Unlike views, fragments have no dedicated controller, though other objects can be supplied in their place during instantiation.