Two components are required for any list implementation in Android: a
ListView widget and an adapter. The
ListView widget is an object that can display a vertical list of items that can be scrolled through. An
Adapter is dynamically associated with the
ListView. The adapter provides access to the underlying data source for the list. In the case of a simple list, after an adapter is associated with the widget, insertion of data as a list item is handled automatically. In the case of a complex list, the developer must create a subclass of an
Adapter object and code the display and behavior of the list in the new subclass.