Events in classical and interactive reports

1. LOAD-OF-PROGRAM
 First event to be called before any of the other ABAP code is processed

2. INITIALIZATION
 Called after the abap selection screen code has been processed (i.e. parameters, select-options etc) but before these are displayed to the user. So you can use it to initialize input fields of the selection screen or change the default values of these before the user gets to enter data into them.

3. AT SELECTION SCREEN OUTPUT
 This is called just before the selection screen is displayed and can be used to manipulate the actual selection screen attributes using teh loop at screen functionality. This allows you to do things like hide fields, grey them out so they are output only or make them intensified etc.

 LOOP AT SCREEN.
  IF SCREEN-name = 'P_FIELd1'.
    SCREEN-INTENSIFIED = '1'.
    MODIFY SCREEN.
    CONTINUE.
  ENDIF.
 ENDLOOP.

 AT SELECTION-SCREEN ON
 This allows you to add processing to a selection screen field for when it is chnaged, user presses F1 or F4 etc using the following parameters

 <parameter1>
 Block <block1>
 HELP-REQUEST for <parameter1> (i.e. When press F1)
 VALUE-REQUEST for <parameter1> (i.e. When press F4)
 RADIOBUTTON for <parameter1> (i.e. When press F4)

 AT SELECTION-SCREEN ON P_FIELD1.
 AT SELECTION-SCREEN ON help-request for P_FIELD1.
4. START-OF-SELECTION
 This is the first event after all screen selection processing has been completed. If no other events are declared then there is no need to manually code this event as all processing statements will be automatically assigned to an implicit START-OF-SELECTION block. It is a good ideal to put it in though as it separates the code and makes it easier to read. GGenerally you would put all you data selection ABAP code within this event.

5. TOP-OF-PAGE
 This is called when a new page is started with an ABAP list and is used to display a header for the list.

6.AT LINE-SELECTION:Allows the user to interact with the lists.
7.AT USER-COMMAND:USed for handling Push buttons.
8.SET PF-STATUS:Provides User Interface.
9. TOP-OF-PAGE During LINE_SELECTION
 If you use the 'DURING LINE-SELECTION' addition this event is also triggered when creating detailed lists.

10. END-OF-PAGE
 This is displayed at the end of each page if there is a line reservation in the addition LINE-COUNT of the initiating statement for a page footer.

 REPORT demo_rep NO STANDARD PAGE HEADING
                            LINE-COUNT 0(1).



11. END-OF-SELECTION
 If your report is linked to a logical database this event is called after the logical database has completely finished its work. Otherwise this event is trigged after the START-OF-SELECTION event so you would generally use it to processes the data retrieved in that event.