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ABAP Tutorials -
ABAP UI Programming
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Written by admin
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Saturday, 13 September 2008 16:06 |
 In ABAP, there are two different types of programs: Report programs and online programs.
Report programs produce lists and can be divided into conventional reports and interactive reports. Conventional reports do not allow interaction by the user; therefore, the basic list contains extensive information that the user must often sort through to find the relevant data.
Interactive reports allow interaction by the user; therefore, the user can produce secondary, detailed lists off of the basic list by choosing the relevant data and requesting more information.
Online programs (also called module pool programs, dialog programs, or transactions) do not produce lists. These programs are a collection of screens, their Flow Logic, and the code within the main ABAP program. The term “screen” refers to the actual, physical image that the users sees.
The term “flow logic” refers to the code behind the screens (i.e., the logic that initialises screens and responds to a user’s requests on the screens). Each screen has its own Flow Logic. The term “dynpro” (dynamic program) refers to the combination of the screen and its Flow Logic. Online Programs can only be started using a transaction code, in which an initial screen is defined
When creating an online program, you will use many tools within the ABAP Development Workbench: Screen Painter, ABAP Editor, Menu Painter, ABAP Dictionary, and Object Navigator.
The Screen Painter is used to maintain all components of the screens.
The ABAP Editor is used to maintain the main ABAP program. This program consists of data declarations and modules. The ABAP modules contain the main processing logic of the online program and are “called” from within the Flow Logic of the screens.
The Menu Painter is used to maintain the graphical user interface (GUI) which consists of the function key assignments, standard toolbar, application toolbar, menubar, and titlebar.
The ABAP Dictionary is used to link dictionary field definitions to screen fields as well as to create program work areas (with the TABLES statement).
You should always use the Object Navigator to create online programs because the system will automatically maintain an online program’s sub-objects and you will be able to see the hierarchy list of these sub-objects. From this hierarchy list, you will be able to branch to the Screen Painter, ABAP Editor, Menu Painter, and ABAP Dictionary.
Screen Components
The Screen Painter is used to maintain all components of a screen: Screen attributes, screen layout, field attributes, and Flow Logic. The screen attributes refer to the basic characteristics of a particular screen. For example, the type of screen and the size of the screen.
The screen layout refers to the physical appearance of the screen. Some of the possible elements a screen can contain include: Text fields, input/output templates, radio buttons, check boxes, frames, and pushbuttons. The screen layout is maintained in the Fullscreen Editor of the Screen Painter.
The field attributes refer to the characteristics of each field (element) for a particular screen. For example, the type of field and the length of the field. Field attributes are maintained in the Field List of the Screen Painter.
The Flow Logic refers to the code behind the screens. It is important to remember that Flow Logic commands are different from ABAP commands (e.g., IF … ENDIF is not valid in Flow Logic). Each screen has its own Flow Logic which is divided into two main events:
- PROCESS BEFORE OUTPUT (PBO) - event processed before the screen is displayed.
- PROCESS AFTER INPUT (PAI) - event processed after the user has invoked a function code (e.g., clicked on a push button) or pressed the ‘Enter’ key.
Each screen must be activated. If you make a change to any component of a screen, the screen must be re-activated before execution.
Screen Layout
Some of the elements that can be “painted” on a screen in the Full screen Editor:
Note: Icons can also be used on a screen. Icons can be used on a pushbutton or on a text element.
The Fullscreen Editor supports two modes: Graphical and alphanumeric. The difference in these two modes is the interface:
The graphical mode (available only on Windows 95, Windows NT, and UNIX/Motif platforms) is the more user-friendly mode with a drag-and-drop “painting” interface. With the alphanumeric mode, you “paint” screens using the keyboard and menu paths.
To maintain the Fullscreen Editor mode, use the “Utilities >Settings and then click on the Screen Painter tab. Here you can check or uncheck the Graphical layout editor checkbox.
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