Fragment concept:

Fragment can be considered as a piece of activity.

one activity can be devide into several fragment.

fragmentManager can help to control several fragment in the same activity.

and the fragment can be static and dynamic. 

U can create the static fragment with sample xml, but it will appear fixed with activity “onCreat”.

U also can create the dynamic fragment with a.xml and b.xml in same content.xml, then 

use “listener” method to get √ some input to decide the content.xml shows “a.xml”or “b.xml”

all the control program written in the java.class.

we need to learn how to transfer the data from fragment to activity and inverse way.