Although we can always find certain method to deal with it, such as function code 'NP', 'POPO', considering some extreme situation: there is only one line visible one the screen, our BDC program should display an error message. (See transaction 'ME21', we you resize your screen to let only one row visible, you can not enter mutiple lines on this screen even you use 'NP')
we can determine the number of visible lines on Transaction Screen from our Calling BDC program.
Demo ABAP code has two purposes:
1. how to determine number of visible lines and how to calculte page number;
(the 'calpage' routine has been modify to meet general purpose usage)
2. using field symbol in BDC program, please pay special attention to the difference
in Static ASSIGN and Dynamic ASSIGN.
Step1: go to screen painter to display the screen 121, then we can count the fixed line on this screen, there is 7 lines above the steploop and 2 lines below the steploop, so there are total 9 fixed lines on this screen. This means except these 9 lines, all the other line is for step loop.
Then have a look at steploop itselp, one entry of it will occupy two lines.
(Be careful, for table control, the head and the bottom scroll bar will possess another two fixed lines, and there is a maximum number for table line)
Now we have : FixedLine = 9
LoopLine = 2(for table control, LoopLine is always equal to 1)
Step2: go to transaction itself(ME21) to see how it roll page, in ME21, the first line of new page is always occupied by the last line of last page, so it begin with index '02', but in some other case, fisrt line is empty and ready for input.
Now we have: FirstLine = 0
or FirstLine = 1 ( in our case, FirstLine is 1 because the first line of new page is fulfilled)
Step3: write a subroutine calcalculating number of pages
(here, the name of actual parameter is the same as formal parameter)
global data: FixedLine type i, " number of fixed line on a certain screen
LoopLine type i, " the number of lines occupied by one steploop item
FirstLine type i, " possbile value 0 or 1, 0 stand for the first line of new " scrolling screen is empty, otherwise is 1
Dataline type i, " number of items you will use in BDC, using DESCRIBE to get
pageno type i, " you need to scroll screen how many times.
line type i, " number of lines appears on the screen.
index(2) type N, " the screen index for certain item
begin type i, " from parameter of loop
end type i. " to parameter of loop
*in code sample, the DataTable-linindex stands for the table index number of this line
form calpage using FixedLine type i (see step 1)
LoopLine type i (see step 1)
FirstLine type i (see step 2)
DataLine type i ( this is the item number you will enter in transaction)
changing pageno type i (return the number of page, depends on run-time visible line in table control/ Step Loop)
changing line type i.(visible lines one the screen)
data: midd type i,
vline type i, "visible lines
if DataLine eq 0.
Message eXXX.
endif.
vline = ( sy-srows - FixedLine ) div LoopLine.
*for table control, you should compare vline with maximum line of
*table control, then take the small one that is min(vline, maximum)
*here only illustrate step loop
if FirstLine eq 0.
pageno = DataLine div vline.
if pageno eq 0.
pageno = pageno + 1.
endif.
elseif FirstLine eq 1.
pageno = ( DataLine - 1 ) div ( vline - 1 ) + 1.
midd = ( DataLine - 1 ) mod ( vline - 1).
if midd = 0 and DataLine gt 1.
pageno = pageno - 1.
endif.
endif.
line = vline.
endform.
Step4 write a subroutine to calculate the line index for each item.
form calindex using Line type i (visible lines on the screen)
FirstLine type i(see step 2)
LineIndex type i(item index)
changing Index type n. (index on the screen)
if FirstLine = 0.
index = LineIndex mod Line.
if index = '00'.
index = Line.
endif.
elseif FirstLine = 1.
index = LineIndex mod ( Line - 1 ).
if ( index between 1 and 0 ) and LineIndex gt 1.
index = index + Line - 1.
endif.
if Line = 2.
index = index + Line - 1.
endif.
endif.
endform.
Step5 write a subroutine to calculate the loop range.
form calrange using Line type i ( visible lines on the screen)
DataLine type i
FirstLine type i
loopindex like sy-index
changing begin type i
end type i.
If FirstLine = 0.
if loopindex = 1.
begin = 1.
if DataLine <= Line. end = DataLine. else. end = Line. endif. elseif loopindex gt 1. begin = Line * ( loopindex - 1 ) + 1. end = Line * loopindex. if end gt DataLine. end = DataLine. endif. endif. elseif FirstLine = 1. if loopindex = 1. begin = 1. if DataLine <= Line. end = DataLine. else. end = Line. endif. elseif loop index gt 1. begin = ( Line - 1 ) * ( loopindex - 1 ) + 2. end = ( Line - 1 ) * ( loopindex - 1 ) + Line. if end gt DataLine. end = DataLine. endif. endif. endif. endform. Step6 using field sysbol in your BDC, for example: in ME21, but you should calculate each item will correponding to which index in steploop/Table Control form creat_bdc. field-symbols:
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