Lists are displayed in a special container screen. As with all other screens, you can link a dialog status to it using the SET PF-STATUS statement. In the dialog status, you link function codes to function keys, menu entries, icons in the standard toolbar, and pushbuttons in the application toolbar.
On a normal screen, a user action triggers the PAI event. In the screen flow logic, you code a processing block that calls ABAP dialog modules in this event. In list processing, the event is intercepted by the list processor and processed. Instead of calling dialog modules, one of the three following list events may be called, depending on the function code triggered in the ABAP runtime environment by the user .
AT PFnn (obsolete)
If you have written the corresponding event blocks in the ABAP your program, they are executed. You can access the function code in the sy-ucomm field.
The output from any list statements that you write in these event blocks is written to detail lists. With one ABAP program, you can maintain one basic list and up to 19 detail lists.