CALLBACK Verb - Register BBj Subroutine

Syntax

CALLBACK (eventType,subroutineName,contextID,{controlID})

CALLBACK (eventType,publicProgramEntryPoint,contextID,{controlID})

Description

A CALLBACK is used to execute a block of code at a given location when a specific event occurs. In some cases, this is tied to a specific control via the controlID.

The CALLBACK verb will implicitly GOSUB to the subroutine specified in subroutineName. Since the block of code executed at subroutineName is arrived at via an implicit GOSUB, a RETURN is required at the end of the subroutine.

The CALLBACK implicitly CALLs the publicProgram at the given EntryPoint when the CALLBACK VERB uses the publicProgramEntryPoint syntax (ie: "publicProgram::EntryPoint"). Since a CALL has been made to a public program, an ENTER may optionally be used at the beginning, and a EXIT is required at the end.

CALLBACKS must be registered before the PROCESS_EVENTS verb or within a SUBROUTINE that is called in response to an event.

The REMOVE_CALLBACK verb removes event handling for the eventType (specified event for a control).

For more information, see PROCESS_EVENTS.

Parameter	Description
eventType	An event type as seen in the table below.
subroutineName	A name of a subroutine that starts with and Alpha character and contains any number of alpha, numeric, and underscore characters.
contextID	An integer value between 0 and 32767.
controlID	Control ID number, which must be an integer between 1 and 32767 and unique within a given top-level window. Optional for window events.
publicProgramEntryPoint	A string of the form "publicProgramName::entryPoint". This parameter must be a BBj string expression: This is valid: CALLBACK(ON_BUTTON_PUSH,"foo::bar",0,101) And so is this: SUB$="foo::bar" CALLBACK(ON_BUTTON_PUSH,SUB$,0,101) But this is a syntax error: CALLBACK(ON_BUTTON_PUSH,foo::bar,0,101)

Window Events

Callback Syntax	Event	Code
ON_ACTIVATE	Activation	A
ON_CLOSE	Window Close Box	X
ON_COLOR_CHANGE	System Color Change	s
ON_DEACTIVATE	Activation	A
ON_DOUBLE_CLICK	Mouse Double-Click	2
ON_KEYPRESS	Keypress	t
ON_MDI_CLOSING (BBj 6.0 and higher)	MDI Closing Event	M
ON_MINIMIZE	Activation	A
ON_MOUSE_DOWN	Mouse Button Down	d
ON_MOUSE_ENTER	Mouse Enter/Exit Event	E
ON_MOUSE_EXIT	Mouse Enter/Exit Event	E
ON_MOUSE_MOVE	Mouse Move	m
ON_MOUSE_SCROLL (BBj 6.0 and higher)	Mouse Scroll Wheel	w
ON_MOUSE_UP	Mouse Button Up	u
ON_RESIZE	Window Resize	S
ON_RESTORE	Activation	A
ON_SCREEN_RESIZE	Screen Resize Event	s
ON_WINDOW_GAINED_FOCUS (BBj 6.0 and higher)	Window Focus Gained/Lost Event	F
ON_WINDOW_LOST_FOCUS (BBj 6.0 and higher)	Window Focus Gained/Lost Event	F
ON_WINDOW_MOVE (BBj 6.0 and higher)	Window Move Event	L
ON_WINDOW_SCROLL	Scrollbar Move	p

Menu Events

Callback Syntax	Event	Code
ON_MENU_ITEM_SELECT	Menu Selection	C

Popup Menu Events

Callback Syntax	Event	Code
ON_POPUP_ITEM_SELECT	Popup Menu Selection	r

Control Events

Callback Syntax	Event	Code
ON_BUTTON_PUSH	Push Button Event	B
ON_CHECK_OFF	Check/Uncheck Event	c
ON_CHECK_ON	Check/Uncheck Event	c
ON_COLORCHOOSER_APPROVE (BBj 7.0 and higher)	ColorChooser Approve Event
ON_COLORCHOOSER_CANCEL (BBj 7.0 and higher)	ColorChooser Cancel Event
ON_COLORCHOOSER_CHANGE (BBj 7.0 and higher)	ColorChooser Change Event
ON_CONTROL_SCROLL	Scrollbar Move Event	p
ON_CONTROL_VALIDATION (BBj 5.0 and higher)	Control Validation Event	v
ON_DB_GRID_ROW_CHANGE_REQUEST (BBj 7.0 and higher)	N/A
ON_DRAG_SOURCE_DROP (BBj 7.0 and higher)	Drag Source Drop Event	O
ON_DROP_TARGET_DROP (BBj 7.0 and higher)	Drop Target Drop Event	D
ON_EDIT_KEYPRESS	Edit Control Notify	N (Notify code 1)
ON_EDIT_MODIFY	Edit Control Modify Event	e
ON_FILECHOOSER_APPROVE (BBj 7.0 and higher)	FileChooser Approve Event	x
ON_FILECHOOSER_CANCEL (BBj 7.0 and higher)	FileChooser Cancel Event	x
ON_FILECHOOSER_CHANGE (BBj 13.0 and higher)	FileChooser Change Event	x
ON_FILECHOOSER_FILTER (BBj 13.0 and higher)	FileChooser Filter Event	x
ON_FONTCHOOSER_APPROVE (BBj 7.0 and higher)	FontChooser Approve Event	x
ON_FONTCHOOSER_CANCEL (BBj 7.0 and higher)	FontChooser Cancel Event	x
ON_FONTCHOOSER_CHANGE (BBj 7.0 and higher)	FontChooser Change Event	x
ON_FORM_VALIDATION (BBj 5.0 and higher)	Form Validation Event	V
ON_GAINED_FOCUS	Control Focus Gained/Lost Event	f
ON_GRID_CELL_MODIFY	EDITCHANGE Grid Notify Event	N (Notify code 5)
ON_GRID_CELL_QUERY (BBj 8.0 and higher)	Grid Cell Query Event	N (Notify code 33)
ON_GRID_CELL_VALIDATION (BBj 5.0 and higher)	Grid Cell Validation Event	N (Notify code 32)
ON_GRID_CHECK_OFF	CELLCHECKED Grid Control Event	N (Notify code 30)
ON_GRID_CHECK_ON	CELLCHECKED Grid Control Event	N (Notify code 30)
ON_GRID_COLUMN_SIZE	COLUMNSIZED Grid Notify Event	N (Notify code 1)
ON_GRID_DOUBLE_CLICK	DCLICKED Grid Notify Event	N (Notify code 3)
ON_GRID_DRAG_DROP	DRAGDROP Grid Notify Event	N (Notify code 4)
ON_GRID_EDIT_START	EDITSET Grid Notify Event	N (Notify code 8)
ON_GRID_EDIT_STOP	EDITKILL Grid Notify Event	N (Notify code 7)
ON_GRID_ENTER_KEY	ENTER Grid Notify Event	N (Notify code 9)
ON_GRID_ERROR	ERROR Grid Notify Event	N (Notify code 29)
ON_GRID_GAINED_FOCUS	SETFOCUS	N (Notify code 20)
ON_GRID_HIT_BOTTOM	HITBOTTOM Grid Notify Event	N (Notify code 10)
ON_GRID_HIT_TOP	HITTOP Grid Notify Event	N (Notify code 11)
ON_GRID_KEYPRESS	KEYBOARD Grid Notify Event	N (Notify code 12)
ON_GRID_LEFT_COLUMN_CHANGE	LEFTCOLCHANGE Grid Notify Event	N (Notify code 16)
ON_GRID_LIST_CANCEL (BBj 15.0 and higher)	LISTCANCEL Grid Notify Event	N (Notify code 34)
ON_GRID_LIST_CHANGE (BBj 15.0 and higher)	LISTCHANGE Grid Notify Event	N (Notify code 35)
ON_GRID_LIST_CLICK (BBj 15.0 and higher)	LISTCLICK Grid Notify Event	N (Notify code 36)
ON_GRID_LIST_CLOSE (BBj 15.0 and higher)	LISTCLOSE Grid Notify Event	N (Notify code 37)
ON_GRID_LIST_OPEN (BBj 15.0 and higher)	LISTOPEN Grid Notify Event	N (Notify code 38)
ON_GRID_LIST_SELECT (BBj 15.0 and higher)	LISTSELECT Grid Notify Event	N (Notify code 39)
ON_GRID_LOST_FOCUS	KILLFOCUS	N (Notify code 13)
ON_GRID_MOUSE_DOWN	LCLICKED Grid Notify Event LCLICKED2 Grid Notify Event	N (Notify code 14) N (Notify code 15)
ON_GRID_MOUSE_DRAG	MOUSECAPTURE Grid Notify Event	N (Notify code 17)
ON_GRID_MOUSE_MOVE	MOUSECAPTURE Grid Notify Event	N (Notify code 17)
ON_GRID_MOUSE_UP	LCLICKED Grid Notify Event	N (Notify code 14)
ON_GRID_RIGHT_MOUSE_DOWN	RCLICKED Grid Notify Event	N (Notify code 18)
ON_GRID_RIGHT_MOUSE_UP	RCLICKED Grid Notify Event	N (Notify code 18)
ON_GRID_ROW_DELETE	ROWDELETE Grid Notify Event	N (Notify code 25)
ON_GRID_ROW_INSERT	ROWINSERT Grid Notify Event	N (Notify code 24)
ON_GRID_ROW_INSERT_CANCEL	ROWCANCEL Grid Notify Event	N (Notify code 26)
ON_GRID_ROW_UPDATE	ROWUPDATE Grid Notify Event	N (Notify code 27)
ON_GRID_ROW_VALIDATION (BBj 5.0 and higher)	ROWVALIDATION Notify Event	N (Notify code 31)
ON_GRID_SELECT_COLUMN	COLCHANGE Grid Notify Event	N (Notify code 2)
ON_GRID_SELECT_ROW	ROWCHANGE Grid Notify Event	N (Notify code 19)
ON_GRID_SPECIAL_KEY	EDITKEY Grid Notify Event	N (Notify code 6)
ON_GRID_TOP_ROW_CHANGE	TOPROWCHANGE Grid Notify Event	N (Notify code 21)
ON_GRID_UPDATE	TABLEUPDATE Grid Notify Event	N (Notify code 22)
ON_HYPERLINK_ACTIVATE (BBj 7.0 and higher)	Hyperlink Activate Event	x
ON_HYPERLINK_ENTER (BBj 7.0 and higher)	Hyperlink Enter Event	x
ON_HYPERLINK_EXIT (BBj 7.0 and higher)	Hyperlink Exit Event	x
ON_INPUT_KEYPRESS	Input Control Keypress	N (Notify Code 1)
ON_LIST_CANCEL (BBj 5.0 and higher)	List Button and List Edit Notify Events	N (Notify code 4)
ON_LIST_CHANGE	List Button and List Edit Notify Events	N (Notify code 5)
ON_LIST_CLICK	List Item Click Event	l (lower case L)
ON_LIST_CLOSE	List Button and List Edit Notify Events	N (Notify code 3)
ON_LIST_DOUBLE_CLICK	List Item Click Event	l (lower case L)
ON_LIST_OPEN	List Button and List Edit Notify Events	N (Notify code 1)
ON_LIST_SELECT	List Button and List Edit Notify Events	N (Notify code 2)
ON_LOST_FOCUS	Control Focus Gained/Lost Event	f
ON_MOUSE_ENTER	Mouse Enter/Exit Event	E
ON_MOUSE_EXIT	Mouse Enter/Exit Event	E
ON_NAV_FIRST (BBj 6.0 and higher)	Navigator Notify Event	N (Notify code 1)
ON_NAV_LAST (BBj 6.0 and higher)	Navigator Notify Event	N (Notify code 1)
ON_NAV_NEXT (BBj 6.0 and higher)	Navigator Notify Event	N (Notify code 1)
ON_NAV_PREVIOUS (BBj 6.0 and higher)	Navigator Notify Event	N (Notify code 1)
ON_PAGE_LOADED (BBj 7.0 and higher)	Page Loaded Event
ON_POPUP_REQUEST	Popup Request Event	p
ON_RIGHT_MOUSE_DOWN (BBj 2.01 and higher)	Right Mouse Button Down Event	R
ON_SPIN (BBj 7.0 and higher)	N/A
ON_TAB_DESELECT	Tab Selection Notify Event	N (Notify code 3)
ON_TAB_KEYPRESS	Keypress Notify Event - Tab Control	N (Notify code 1)
ON_TAB_SELECT	Tab Selection Notify Event	N (Notify code 2)
ON_TOOL_BUTTON_PUSH	Tool Button Push Event	b
ON_TREE_COLLAPSE	Tree Node Collapsed	N (Notify Code 4)
ON_TREE_DESELECT	Tree Node Deselected	N (Notify Code 2)
ON_TREE_DOUBLE_CLICK	Double-click on Tree	N (Notify Code 7)
ON_TREE_EDIT_STOP	Tree Node Edit Stopped	N (Notify Code 5)
ON_TREE_EXPAND	Tree Node Expanded	N (Notify Code 3)
ON_TREE_MOUSE_DOWN	Left Mouse Down	N (Notify Code 6)
ON_TREE_MOUSE_UP	Left Mouse Up	N (Notify Code 6)
ON_TREE_RIGHT_MOUSE_DOWN	Right Mouse Down	N (Notify Code 8)
ON_TREE_RIGHT_MOUSE_UP	Right Mouse Up	N (Notify Code 8)
ON_TREE_SELECT	Tree Node Selected	N (Notify Code 1)

Other Events

Callback Syntax	Event	Code
ON_GEOLOCATION_POSITION (BBj 11.0 and higher)	N/A	G
ON_GEOLOCATION_WATCH (BBj 11.0 and higher)	N/A	G
ON_NAMESPACE_SET (BBj 6.0 and higher)	BBjNamespaceEvent	N (Notify Code 1)
ON_NAMESPACE_CHANGE (BBj 6.0 and higher)	BBjNamespaceEvent	N (Notify Code 2)
ON_TIMER (BBj 6.0 and higher)	Timer Event	T
ON_WEB_CONNECTION (BBj 12.0 and higher)	N/A

Example

rem 'CallBack Example

SYSGUI=UNT
OPEN (SYSGUI)"X0"
SysGui! = BBjAPI().getSysGui()

rem 'Create Controls
PRINT (SYSGUI)'WINDOW'(50,50,400,200,"Example",$00090003$)
PRINT (SYSGUI)'EDIT'(100,50,50,125,25,"",$$)
PRINT (SYSGUI)'EDIT'(103,200,50,125,25,"",$$)
PRINT (SYSGUI)'BUTTON'(110,62,125,75,25,"Button 1",$$)
PRINT (SYSGUI)'BUTTON'(111,212,125,75,25,"Button 2",$$)

rem 'Build the event base info templates
DIM GENERIC$:NOTICETPL(0,0)
DIM EVENT$:TMPL(SYSGUI)

CONTEXT = 0
VAR = 2

rem 'PublicProgramEntryPoint
CALLBACK(ON_BUTTON_PUSH,pgm(-2)+"::BUTTON1_PUSH",CONTEXT,110)

rem 'Subroutine Name
CALLBACK(ON_BUTTON_PUSH,BUTTON2_PUSH,CONTEXT,111)
CALLBACK(ON_EDIT_MODIFY,EDIT_MODIFY,CONTEXT,100)
CALLBACK(ON_EDIT_MODIFY,EDIT_MODIFY,CONTEXT,103)
CALLBACK(ON_CLOSE,EXIT_PROGRAM,CONTEXT,0)

rem 'Process Events
process_events

rem 'This Callback is registered using PublicProgramEntryPoint
rem 'and therefore can Optionally do an ENTER
rem 'and always uses an EXIT.
BUTTON1_PUSH:
    ENTER
    PRINT (SYSGUI)'TITLE'(100,"Button 1: VAR = "+str(VAR))
    PRINT (SYSGUI)'TITLE'(103,"")
    EXIT

rem 'This Callback is registered using SubroutineName
rem 'and therfore does a return
BUTTON2_PUSH:
    PRINT (SYSGUI)'TITLE'(100,"")
    PRINT (SYSGUI)'TITLE'(103,"You Pressed Button 2!")
return

rem 'This Callback is registered using SubroutineName
rem 'and therfore does a return
EDIT_MODIFY:
    event! = sysgui!.getLastEvent()
    print "Edit control contains: ",event!.getText()
return

EXIT_PROGRAM:
release