User Interface Elements 
Background
Various libraries with user interface elements (UI elements) are available in the Web Dynpro Explorer for creating your interface layout. These standard UI elements include for instance a button, a table or an input field.
These UI elements support general user interaction and screen display within a Web application. The UI elements enable quick and simple design of user-friendly application user interfaces, independently of the platform and the front end.
UI elements that belong to each other are grouped in UI element libraries.
The grouping makes it easier to develop additional UI elements in the different development groups and the structure provides a better overview of the UI elements. In addition, it is easier to maintain the individual libraries.
The interface elements in Web Dynpro for ABAP behave the same way as those in Web Dynpro for Java.
Each interface element is based on an ABAP class. The class library of UI elements contains abstract and concrete UI element classes. Abstract classes are used to provide common characteristics for concrete classes. Abstract classes cannot be instantiated. Only concrete classes can be instantiated and their instances can be placed in a view during the application development.
Use
Web Dynpro allows a design-oriented development of user interfaces and provides a comprehensive class library of UI elements for application programming.
UI elements can be used within a Web application to execute actions, display and enter text or display graphics. Buttons, checkboxes, and radio buttons are typical UI elements, for example. Some of the UI elements provided by Web Dynpro can automatically execute generic services.
When developing the Web Dynpro applications, the UI elements are placed in a view displayed in a specific screen area at runtime. Web Dynpro supports not only the modeling of the view contents but also the navigation between the individual view contents within the Web application.
Each UI element has different properties, events, and aggregations that determine the appearance and behavior of the UI element on the user interface. A detailed description of the properties, actions, and aggregations that are associated with a specific UI can be found in the following sections.
Standard Library (Simple Elements)
Standard Library (Complex Elements)
Standard Library (Container Elements)
General Information contains information valid for all UI elements.