Make second line appear and disappear on a subfile

I was asked how to do this by someone who said that no-one in his department knew how to: have a second record appear in a subfile when a function key is pressed, and disappear when the function key was pressed again.

Fortunately this is a simple thing to do with just three keywords in the display file's DDS:

• SFLDROP
• SFLFOLD
• SFLMODE

And there is not much we have to do in the RPG program that uses the subfile.

I have deliberately stripped down the display file and RPG code to what I consider a minimum to, in my opinion, makes it easier to understand.

Let me jump right in and show you the display file I will be using in this example:

01 A INDARA 02 A CA03(03 'F3=Exit') *------------------------------------------------------------------------- 03 A R SFL01 SFL 04 A 3 3'First line' 05 A Z1RRN 3S 0O 3 15 06 A 4 5'Second line' *------------------------------------------------------------------------- 07 A R CTL01 SFLCTL(SFL01) 08 A SFLSIZ(0100) 09 A SFLPAG(0010) 10 A SFLDSP 11 A SFLDSPCTL 12 A 30 SFLEND(*MORE) 13 A 31 SFLDROP(CA11) 14 A N31 SFLFOLD(CA11) 15 A SFLMODE(&MODE) 16 A MODE 1A H 17 A 1 2'TEST DISPLAY FILE'

This display file consists of three parts:

1. Header level keywords, lines 1 and 2
2. Subfile record format, lines 3 – 6
3. Subfile control record format, lines 7 – 17

Line 1: The INDARA means that I using the indicator area in the display file and the indicator data structure in my RPG program. That way I can give the indicators real names, rather than them just being anonymous numbers.

Line 2: I will be using indicator 3 to exit the program.

Lines 3 – 5: I think this is the simplest subfile record format I have ever created. Notice that lines 4 and 5 will display on the same subfile line, while line 6 will display on the following line.

Line 7: This line tells the display that this is the subfile control record format for the previous subfile record format.

Lines 8 and 9: This is a "load all" subfile. The subfile can contain a maximum of 100 records, and will display a maximum of 10 on each page.

Lines 10 – 11: as I know this subfile is going to contain data I don't need to condition these keywords with indicators.

Line 12: I prefer "More..." and "Bottom" at the bottom of my subfiles. To use these I have condition the keyword with an indicator.

Line 13: SFLDROP: This displays just the first line of the subfile records. When the given function key, F11, is pressed it open up and display the second line of the subfile records.

Line 14: SFLFOLD: This displays the second line of the record. When the given function key is pressed the second line of the subfile is not displayed.

Lines 15 and 16: SFLMOD and the hidden variable MODE allows me to retrieve which mode, "expanded" or "contracted", the subfile is in.

Line 17: Display heading.

Now onto the RPG program:

01 **free 02 ctl-opt option(*nodebugio:*srcstmt:*nounref) dftactgrp(*no) ; 03 dcl-f TESTDSPF workstn indds(Dspf) sfile(SFL01:Z1RRN) ; 04 dcl-ds Dspf qualified ; 05 Exit ind pos(3) ; 06 SflMore ind pos(30) ; 07 SflMode ind pos(31) ; 08 end-ds ; 09 LoadSubfile() ; 10 Dspf.SflMode = '1' ; //=1 lines 11 Dspf.SflMode = '0' ; //=2 lines 12 Mode = Dspf.SflMode ; 13 dow (1 = 1) ; 14 exfmt CTL01 ; 15 if (Dspf.Exit) ; 16 leave ; 17 endif ; 18 Dspf.SflMode = Mode ; 19 enddo ; 20 *inlr = *on ;

Line 1: If the RPG ain't free it ain't my code.

Line 2: These are my favorite control options I add to all my RPG programs.

Line 3: This is the file definition for my display file. The INDDS gives the name of the indicator data structure. SFILE tells the program which field is the "key", relative record number, for the subfile I will be using.

Lines 4 - 8: This is the indicator data structure. I will be using just three indicators from the display file, and these are the name I will be calling them in this program.

Line 9: This subprocedure is where I load the subfile. I will show the code for it later in this post.

Lines 10 and 11: These lines are here for testing purposes only. In the real world you would use line 10 or 11, not both.

Line 12: Here I set the field Mode so that the right variation of the subfile is displayed.

Lines 13 – 19: I am using a Do loop within which I am displaying the subfile, including control record.

Line 18: The Mode field in the display file is updated with which version of the subfile is shown. I take that value and update the indicator that controls either SFLDROP or SFLFOLD version of the subfile.

I said I would show the subprocedure that loaded the subfile, and here it is:

21 dcl-proc LoadSubfile ; 22 for Z1RRN = 1 to 30 ; 23 write SFL01 ; 24 endfor ; 25 Dspf.SflMore = *on ; 26 end-proc ;

Lines 22 – 24: I am using a For group to write 30 records to the subfile.

Line 25: I need to set on this indicator so that I will see More… and Bottom at the bottom of my subfile screens.

So what do I see when I call this program?

TEST DISPLAY FILE First line 001 Second line First line 002 Second line First line 003 Second line First line 004 Second line First line 005 Second line First line 006 Second line First line 007 Second line First line 008 Second line First line 009 Second line First line 010 Second line More...

As the mode is zero both lines of the subfile record is displayed.

Now I press F11 and the subfile collapses, removing the second lines from the subfile records.

TEST DISPLAY FILE First line 001 First line 002 First line 003 First line 004 First line 005 First line 006 First line 007 First line 008 First line 009 First line 010 First line 011 First line 012 First line 013 First line 014 First line 015 First line 016 First line 017 First line 018 First line 019 First line 020 More...

I can press F11 to toggle between the two variants to my heart's content, and page up and down to see the rest of the subfile's records. Yes, the code is as easy as that.

You can learn more about this from the IBM website:

• SFLDROP
• SFLFOLD
• SFLMODE

 

This article was written for IBM i 7.4, and should work for some earlier releases too.