A scroll bar. Scroll bars are used when all the content of another control cannot be seen at the same time. They may be oriented horizontally or vertically, and may be displayed in several ways. Scroll bars represent integers, and have a maximum, a minimum, and a current position encapsulated within their model. The on-screen image of a scroll bar is calculated and displayed by the CEikScrollBar object, and user changes to the scroll bar (and hence its model) are reported to an interested class through the MEikScrollBarObserver interface.

The scroll bar frame is a control assemblage manager that relates a control, or control body, to two scroll bars and a corner window. A corner window is that part of the screen that is common to both the horizontal, and the vertical elements of a scroll bar. This class helps with access to, and set up of, scroll bars and also with the layout of the scrolled control or control body. A scroll bar frame is not a control, but it does implement the standard control composite pattern to manage the assemblage.

This mixin is implemented by classes wishing to receive notification about scroll events from a scroll bar. Each scroll bar has a scroll bar observer registered with it in its construction, and will call the HandleScrollEventL() of its observer when the user moves the scroll bar.Scroll bar observers are not owned by their scroll bar, and must be deleted explicitly. It is possible to register the same scroll bar observer with many scroll bars. This class is intended for derivation by all classes interested in scroll events from CEikScrollBar.