ABAP：利用SAP定时器自动刷新ALV
曾于无意之中发现，SAP系统中有个名为CL_GUI_TIMER的类，测试下来发现还是挺好用的，比网上那些自动刷新的例子直观多了。这里我们就做个演示实例。
先做好准备工作：建立程序z04_gui_timer及其屏幕0100，屏幕上画个CUSTOM CONTAINER作为ALV的容器。顺便可以画个退出按钮用于退出界面，这样就省得SET PF-STATUS了。
下面就是我们的程序代码了，其实还是挺简单的：
代码语言：javascript复制REPORT zmatinal_timer.
* 公众号：matinal
CLASS lcl_event_handler DEFINITION DEFERRED.
DATA: ok_code LIKE sy-ucomm,
go_timer TYPE REF TO cl_gui_timer,
go_evt_hndl TYPE REF TO lcl_event_handler.
DATA: gt_spfli TYPE TABLE OF spfli,
go_grid TYPE REF TO cl_gui_alv_grid,
go_container TYPE REF TO cl_gui_custom_container.
START-OF-SELECTION.
CALL SCREEN 0100.
****** Module status_9000 OUTPUT
MODULE status_0100 OUTPUT.
DATA: g_init TYPE flag.
CLEAR ok_code.
IF g_init IS INITIAL.
g_init = 'X'.
PERFORM init_0100.
ENDIF.
ENDMODULE. " status_0100 OUTPUT
****** Module user_command_0100 INPUT
MODULE user_command_0100 INPUT.
CASE ok_code.
WHEN 'EXIT'.
LEAVE PROGRAM.
WHEN OTHERS.
ENDCASE.
ENDMODULE. " user_command_0100 INPUT
****** CLASS lcl_event_handler DEFINITION
CLASS lcl_event_handler DEFINITION.
PUBLIC SECTION.
METHODS:
handle_timer FOR EVENT finished OF cl_gui_timer.
ENDCLASS. "lcl_event_handler DEFINITION
****** CLASS lcl_event_handler IMPLEMENTATION
CLASS lcl_event_handler IMPLEMENTATION.
METHOD handle_timer.
DELETE gt_spfli INDEX 1.
CALL METHOD go_grid->refresh_table_display.
* CALL METHOD go_timer->cancel
* EXCEPTIONS
* OTHERS = 9.
CALL METHOD go_timer->run "必须重新激活定时器
EXCEPTIONS
OTHERS = 9.
ENDMETHOD. "handle_timer
ENDCLASS. "lcl_event_handler IMPLEMENTATION
****** Form init_0100
FORM init_0100.
SELECT * INTO TABLE gt_spfli
FROM spfli UP TO 30 ROWS.
CREATE OBJECT go_container
EXPORTING
container_name = 'CC_ALV'.
CREATE OBJECT go_grid
EXPORTING
i_parent = go_container.
CALL METHOD go_grid->set_table_for_first_display
EXPORTING
i_structure_name = 'SPFLI'
CHANGING
it_outtab = gt_spfli.
CREATE OBJECT go_evt_hndl.
CREATE OBJECT go_timer
EXCEPTIONS
OTHERS = 9.
SET HANDLER go_evt_hndl->handle_timer FOR go_timer.
go_timer->interval = 3. "设置间隔为3秒
CALL METHOD go_timer->run
EXCEPTIONS
OTHERS = 9.
ENDFORM. " init_0100说明：
(1) lcl_event_handler是自定义的类，用于处理cl_gui_timer的EVENT ‘finished’；
(2) 定时器的用法与VC、DELPHI有所不同，上次定时事件处理完毕后，必须CALL METHOD go_timer->run重新激活，如此循环；
(3) 定时器并不会自动触发PAI事件，如有必要则可以在handle_timer中CALL METHOD cl_gui_cfw=>set_new_ok_code来触发；
(4) 虽然我们的例子是基于screen的，但是基于List也是完全可行的。
