A method to create a "change all" checkbox in the column heading of (interactive) reports.

This is an alternative to a commonly used technique, which uses javascript function $f_CheckFirstColumn.
Using that function has a few drawbacks:

• It will always select the first checkbox column of the report, even when that is not the one you want. E.g. in this report it would select the "Was Selected" column instead of the "Select" column, because the sequence of the checkbox columns has been changed.
• $f_CheckFirstColumn does not take into account whether a checkbox is disabled; if it is disabled, you probably don't want to change its status.
• Consequently, the "select all" option is shown even when none of the checkboxes can be changed; not very elegant.

All these drawbacks are addressed by the method shown here.

Notes:

• In Apex 5 and above, you need to explicitly set the Static ID of column EMPNO_CHECKBOX to EMPNO_CHECKBOX for the javascript to work (otherwise an internal id is used). This is not needed in Apex 4.2 and below.
• For dynamic action "P1002_SELECTED_N update (on change)", "Fire On Page Load" has to be set to true. This doesn't seem logical but is needed to get this to work on 1st page load.
• Toggle the "Deptno = 10" filter to see that the "select all" checkbox is only added if there is at least 1 enabled checkbox; adding it when none of the checkboxes can be changed would not make a lot of sense.

Dynamic Actions

• "EMPNO_CHECKBOX label": Adds the "select all" checkbox to the Checkbox column heading. We do this using javascript, otherwise (if you just add this to the column header definition) the checkbox html code also appears in the Actions -> Select Columns list of the report. Not very nice.
• "EMPNO_CHECKBOX_ALL javascript": Toggles the checkboxes in the report whenever the "select all" checkbox change.
• "P1002_SELECTED_N update (on change)": Updates the "Selected" number field, whenever the IR is changed. Not needed for Classic Reports, see below.
• "P1002_SELECTED_N update (after refresh)": Updates the "Selected" number field, whenever the IR is refreshed. We need both this and the "on change" dynamic action (for Interactive Reports anyway), to get both the checkbox selection and the report filter to work.

Page

Identification
	Page ID	1002
	Name	Apex - Reports - Checkboxes

Region

Identification
	Sequence	20
	Title	IR
	Type	Interactive Report
Source
	Source Type	DYNAMIC_QUERY
	Region Source	select apex_item.checkbox2 ( 1, emp.empno, case when emp.job = 'MANAGER' then 'CHECKED' else '' end || ( case when deptno = 10 then ' DISABLED' else '' end) ) as empno_checkbox , apex_item.checkbox2 ( 2, emp.empno, case when emp.job = 'MANAGER' then 'CHECKED' else '' end || ' DISABLED' ) as empno_checkbox_disabled , emp.* from emp

Item

Identification
	Sequence	10
	Name	P1002_SELECTED_N
	Display As	Number Field
User Interface
	Region	IR
Advanced
	Custom Attributes	disabled="disabled"
	Warn on Unsaved Changes	Page Default

Dynamic Action

Identification
	Name	EMPNO_CHECKBOX label
Execution Options
	Sequence	20
When
	Event	After Refresh
	Selection Type	Region
	Region	IR
Advanced
	Event Scope	Static
True Action
Identification
	Action	Execute JavaScript Code
Settings
	Code	cb_array = document.getElementsByName('f01'); for (i=0; i<cb_array.length; i++){ if ( cb_array[i].disabled == false ){ $("#EMPNO_CHECKBOX").html($("#EMPNO_CHECKBOX").html()+'<div style="text-align:center;"><input type="checkbox" id="EMPNO_CHECKBOX_ALL"></div>'); break; } }
Execution Options
	Sequence	10
	Fire On Initialization	Yes

Dynamic Action

Identification
	Name	EMPNO_CHECKBOX_ALL javascript
Execution Options
	Sequence	21
When
	Event	Change
	Selection Type	jQuery Selector
	jQuery Selector(s)	#EMPNO_CHECKBOX_ALL
Advanced
	Event Scope	Dynamic
True Action
Identification
	Action	Execute JavaScript Code
Settings
	Code	cb_array = document.getElementsByName('f01'); for (i=0; i<cb_array.length; i++){ if ( cb_array[i].disabled == false ){ cb_array[i].checked = document.getElementById("EMPNO_CHECKBOX_ALL").checked; } }
Execution Options
	Sequence	10
	Fire On Initialization	No

Dynamic Action

Identification
	Name	P1002_SELECTED_N update (on change)
Execution Options
	Sequence	22
When
	Event	Change
	Selection Type	Region
	Region	IR
Advanced
	Event Scope	Dynamic
True Action
Identification
	Action	Execute JavaScript Code
Settings
	Code	/* Note "Fire On Page Load" has to be true here, doesn't seem logical but is needed to get this to work on 1st page load. */ cb_array = document.getElementsByName('f01'); var selected_n = 0; for (i=0; i<cb_array.length; i++){ if ( cb_array[i].checked ){ selected_n += 1; } } document.getElementById("P1002_SELECTED_N").value = selected_n;
Execution Options
	Sequence	10
	Fire On Initialization	Yes

Dynamic Action

Identification
	Name	P1002_SELECTED_N update (after refresh)
Execution Options
	Sequence	23
When
	Event	After Refresh
	Selection Type	Region
	Region	IR
Advanced
	Event Scope	Dynamic
True Action
Identification
	Action	Execute JavaScript Code
Settings
	Code	cb_array = document.getElementsByName('f01'); var selected_n = 0; for (i=0; i<cb_array.length; i++){ if ( cb_array[i].checked ){ selected_n += 1; } } document.getElementById("P1002_SELECTED_N").value = selected_n;
Execution Options
	Sequence	10
	Fire On Initialization	No