Query about screen as a structure used in table control.

Question

hi all,
plz explain the fields in screen(structure).
when and how it is used.
specialy i/o, o/p,active,
plz give example.

Answer 1

hi,
The screen elements text field, input/output field, status icon, group box, radio button, checkbox, and
pushbutton all have general attributes, Dictionary attributes, program attributes, and display attributes.
The elements subscreen, tabstrip control, and table control have general attributes, and special
attributes relating to the respective type.
We can divide the attributes of an element into:
Statically definable attributes that cannot be changed dynamically
Statically definable attributes that can be changed dynamically
Attributes that can only be changed dynamically
At the beginning of the PBO, the runtime system reads the statically-created and dynamically-modifiable
attributes of each screen element on the current screen into a system table with the line type SCREEN.
Dynamic changes to the attributes of screen elements are temporary.
Using this technique to modify the attributes of a screen element (for example, to change whether an
input/output field is ready for input), you can replace long sequences of separate screens, which are
more costly in terms of both programming time and runtime.
The system table with line type SCREEN will be called SCREEN system table in the following unit.
When a screen is processed, the SCREEN system table contains an entry for each element created in
the Screen Painter for that screen.
The system table SCREEN is initialized at the start of the PBO event for the current screen. To do this, a
system program copies the statically defined attributes of the individual screen elements into the table.
You can then change the dynamically-modifiable attributes of the elements on the screen in a module at
PBO using the following statements: LOOP AT SCREEN.
MODIFY SCREEN.
ENDLOOP.
To do this, you use the structure SCREEN, which is created automatically by the system, and filled with
the values of each successive line of the system table in the loop. Set attributes have the value '1',
attributes that are not set have the value '0'. To change the system table, use MODIFY SCREEN. within
the loop.
To find the element whose attributes you want to modify, you can use a LOOP on the SCREEN table,
and query one of the following fields: SCREEN-NAME, SCREEN-GROUP1 to SCREEN-GROUP4.
You can change the attributes of several screen elements simultaneously at runtime, by including them
in a modification group in the Screen Painter. Assign all elements that will be changed within a single
processing step to a group in the Screen Painter.
To do this, enter a group name for each of the relevant elements in one of the fields GROUP1 …
GROUP4.
You can include each element in up to four modification groups. You can choose any three-character
sequence for the group name. You can assign elements to a modification group either in the element list
or the layout editor in Screen Painter.
You must program your screen modifications in a module that is processed during the PROCESS
BEFORE OUTPUT processing block.
You use a loop through the table SCREEN to change the attributes of an element or a group of
elements. (LOOP AT SCREEN WHERE . . . and READ TABLE SCREEN are not supported).
To activate and deactivate attributes, assign the value 1 (active) or 0 (inactive), and save your changes
using the MODIFY SCREEN statement.
Note that elements you have defined statically in the Screen Painter as invisible cannot be reactivated
with SCREEN-ACTIVE = 1. Instead, use the statement SCREEN-INVISIBLE = 0. However, elements
that you have statically defined as visible in the Screen Painter can dynamically be made invisible. This
has the same effect as the three statements SCREEN-INVISIBLE = 1, SCREEN-INPUT = 0, SCREENOUTPUT
= 0.
There are three steps involved in displaying buffered data from the internal table in the table control:
The system loops through the lines of the table control on the screen. The lines of the screen table are
processed one by one. For each line, the system carries out the following steps:
The current line of the internal table is placed in the work area of the internal table. (Note that it is
possible to scroll in the table on the screen).
The data from the work area of the internal table is copied into the relevant line of the table control.
When you use table controls on a screen, the automatic field transport sequence changes.
In the PBO processing block, data is transferred from the ABAP program to the screen after each loop
pass in the flow logic. The rest of the screen fields are filled, as normal, at the end of the PBO.
In the flow logic, the loop statement
LOOP AT <itab> INTO <wa_itab> WITH CONTROL <tc_name>
starts a loop through the screen table, and reads the line of the internal table corresponding to the
current line of the screen table, placing it in <wa_itab>.
<itab> is the name of the internal table containing the data, <wa_itab> is the name of the work area for
the internal table, and <tc_name> is the name of the table control on the screen.
If the fields in your table control have the same structure and name as those in the work area <wa_itab>,
the system can transport data between the ABAP program and the screen automatically (step 3).
If you are not using the same structure for the table control fields and the work area of the internal table,
you must call a module between LOOP and ENDLOOP that moves the data from the work area
<wa_itab> into the screen fields (MOVE-CORRESPONDING <wa_itab> TO …) .
The system calculates the value of <ctrl>-TOP_LINE when you scroll, but not when you scroll a page at
a time outside the table control.
In order to transfer changed values from the table control back to the internal table the following three
steps must be carried out:
The system loops through the lines of the table control. The lines of the screen table are processed
one by one. For each line, the system carries out the following steps:
The data from the current line of the table control is copied into the header line of the internal table.
The data in the work area must then be placed in the line of the internal table corresponding to the
line of the table control that is being processed. (Note that it is possible to scroll in the table on the
screen).
In the PAI processing block, all screen fields that do not belong to a table control and that are not listed
in a FIELD statement are transported back to the work fields in the ABAP program first.
The contents of the table control are transported line-by-line to the corresponding work area in the ABAP
program in the appropriate loop.
As usual, the fields that occur in FIELD statements are transported directly before that statement.
The structure of the screen tables contain.
NAME
GROUP 1
GROUP 2
GROUP 3
GROUP 4
OUTPUT
REQUIRED
LENGTH
INTENSIFIED
INVISIBLE
ACTIVE
Hope this helps, Do reward.
Edited by: Runal Singh on Mar 13, 2008 10:41 AM