Oracle APEX - Download selected files as zip - IR/IG checkbox selection - checkbox

Question

I referred to this link create a download zip button to download files in zip format in Oracle apex latest version 22.2. It is working fine without any issues but only concern is; it downloads all the files in one zip file. Whereas my requirement is to include a checkbox on a report (either IG or IR) and to download selected files in one zip file.
Below is the table I am referring to. Its from Oracle apex sample files upload and download.
select
ID,
ROW_VERSION_NUMBER,
PROJECT_ID,
FILENAME,
FILE_MIMETYPE,
FILE_CHARSET,
FILE_BLOB,
FILE_COMMENTS,
TAGS,
CREATED,
CREATED_BY,
UPDATED,
UPDATED_BY
from EBA_DEMO_FILES
I tried searching over the internet and found few links pointing to APEX_ZIP, PL/SQL compress blob etc. But could not see any demo or working model similar to the link I provided above.
If anybody has working demo or blog,I request to share it. Many thanks.
Update: As suggested by Koen Lostrie, I am updating Page process code below:
DECLARE
l_id_arr apex_t_varchar2;
l_selected_id_arr apex_t_varchar2;
var_zip blob;
BEGIN
-- push all id values to an array
FOR i IN 1..APEX_APPLICATION.G_F03.COUNT LOOP
apex_string.push(l_id_arr,APEX_APPLICATION.G_F03(i));
FOR j IN 1 .. APEX_APPLICATION.G_F01.COUNT LOOP
IF APEX_APPLICATION.G_F01(j) = APEX_APPLICATION.G_F03(i) THEN
-- push all selected emp_id values to a 2nd array
apex_string.push(l_selected_id_arr,APEX_APPLICATION.G_F03(i));
END IF;
END LOOP;
END LOOP;
-- Create/clear the ZIP collection
APEX_COLLECTION.CREATE_OR_TRUNCATE_COLLECTION(
p_collection_name => 'ZIP');
-- Loop through all the files in the database
begin
for var_file in (select fi.filename, fi.file_blob, pr.project
from eba_demo_files fi
inner join eba_demo_file_projects pr on fi.project_id = pr.id
where fi.id in (SELECT column_value FROM table(apex_string.split(apex_string.join(l_selected_id_arr,':'),':'))))
loop
-- Add each file to the var_zip file
APEX_ZIP.ADD_FILE (
p_zipped_blob => var_zip,
p_file_name => var_file.project || '/' || var_file.filename,
p_content => var_file.file_blob );
end loop;
exception when no_data_found then
-- If there are no files in the database, handle error
raise_application_error(-20001, 'No Files found!');
end;
-- Finish creating the zip file (var_zip)
APEX_ZIP.FINISH(
p_zipped_blob => var_zip);
-- Add var_zip to the blob column of the ZIP collection
APEX_COLLECTION.ADD_MEMBER(
p_collection_name => 'ZIP',
p_blob001 => var_zip);
END;
Once page process is done, follow step 3 and 4 from the link provided in OP.
Below is the updated query:
select
ID,
ROW_VERSION_NUMBER,
PROJECT_ID,
FILENAME,
FILE_MIMETYPE,
FILE_CHARSET,
FILE_BLOB,
FILE_COMMENTS,
TAGS,
CREATED,
CREATED_BY,
UPDATED,
UPDATED_BY,
APEX_ITEM.CHECKBOX(1,ID) checkbox,
APEX_ITEM.TEXT(2,FILENAME) some_text,
APEX_ITEM.HIDDEN(3,ID) hidden_empno
from EBA_DEMO_FILES
Big Thanks to Koen Lostrie.
All credits goes to Koen Lostrie.
Thanks,
Richa

Answer 1

This is just an answer to the last comment - the base question was answered in the comments. The question in the comment is "how do I include APEX_ITEM.HIDDEN columns in my report without hiding the columns".
When the columns are hidden in the report, they're not rendered in the DOM, so the values do not exist when the form is posted. That is the reason you're getting the error.
However, take a step back and check what APEX_ITEM.HIDDEN generates. Add a column of type APEX_ITEM.HIDDEN to the report and inspect the column in the browser tools. It generates an input element of type "hidden", so the value is not shown in the report. So to include the column in your report but not make it visible on the screen, just concatenate it to an existing other column:
In your case, with the select from the question that would be:
select
APEX_ITEM.HIDDEN(3,ID) || APEX_ITEM.HIDDEN(2,FILENAME) || ID,
ROW_VERSION_NUMBER,
PROJECT_ID,
FILENAME,
FILE_MIMETYPE,
FILE_CHARSET,
FILE_BLOB,
FILE_COMMENTS,
TAGS,
CREATED,
CREATED_BY,
UPDATED,
UPDATED_BY,
APEX_ITEM.CHECKBOX(1,ID) checkbox
from EBA_DEMO_FILES
Note that filename can also be in a hidden element.