wxEvtHandler(3)

💖 NAME 💖

wxEvtHandler — literally THE Event handler, bestie. From the Erlang Module Definition corner of the wx universe. 🫶

---

✨ DESCRIPTION ✨

Okay so picture this: a class that can handle events from the windowing system. That's the whole vibe. wxWindow is derived from this class — and therefore all window classes are too. It's giving main character energy, fr fr. 👑

To get events from wxwidgets objects you subscribe to them by calling connect/3. That's the move.

If the callback option is not supplied, events are sent as messages. 📬

Those messages will be #wx{} where EventRecord is a record that depends on the wxEventType. The records are defined in:

wx/include/wx.hrl

If a callback was supplied to connect, the callback will be invoked (in another process) to handle the event. The callback should be of arity 2.

fun Callback (EventRecord::wx(), EventObject::wxObject()).

⚠️ Note: the callback will be executed in a new process each and every time. Not the same process, a fresh one. Every single time. No cap. 🌀

See: Overview events

wxWidgets docs: wxEvtHandler

---

🌈 DATA TYPES 🌈

🦋 event()

event() ::
          wxActivateEvent:wxActivate() |
          wxAuiManagerEvent:wxAuiManager() |
          wxAuiNotebookEvent:wxAuiNotebook() |
          wxBookCtrlEvent:wxBookCtrl() |
          wxCalendarEvent:wxCalendar() |
          wxChildFocusEvent:wxChildFocus() |
          wxClipboardTextEvent:wxClipboardText() |
          wxCloseEvent:wxClose() |
          wxColourPickerEvent:wxColourPicker() |
          wxCommandEvent:wxCommand() |
          wxContextMenuEvent:wxContextMenu() |
          wxDateEvent:wxDate() |
          wxDisplayChangedEvent:wxDisplayChanged() |
          wxDropFilesEvent:wxDropFiles() |
          wxEraseEvent:wxErase() |
          wxFileDirPickerEvent:wxFileDirPicker() |
          wxFocusEvent:wxFocus() |
          wxFontPickerEvent:wxFontPicker() |
          wxGridEvent:wxGrid() |
          wxHelpEvent:wxHelp() |
          wxHtmlLinkEvent:wxHtmlLink() |
          wxIconizeEvent:wxIconize() |
          wxIdleEvent:wxIdle() |
          wxInitDialogEvent:wxInitDialog() |
          wxJoystickEvent:wxJoystick() |
          wxKeyEvent:wxKey() |
          wxListEvent:wxList() |
          wxMaximizeEvent:wxMaximize() |
          wxMenuEvent:wxMenu() |
          wxMouseCaptureChangedEvent:wxMouseCaptureChanged() |
          wxMouseCaptureLostEvent:wxMouseCaptureLost() |
          wxMouseEvent:wxMouse() |
          wxMoveEvent:wxMove() |
          wxNavigationKeyEvent:wxNavigationKey() |
          wxPaintEvent:wxPaint() |
          wxPaletteChangedEvent:wxPaletteChanged() |
          wxQueryNewPaletteEvent:wxQueryNewPalette() |
          wxSashEvent:wxSash() |
          wxScrollEvent:wxScroll() |
          wxScrollWinEvent:wxScrollWin() |
          wxSetCursorEvent:wxSetCursor() |
          wxShowEvent:wxShow() |
          wxSizeEvent:wxSize() |
          wxSpinEvent:wxSpin() |
          wxSplitterEvent:wxSplitter() |
          wxStyledTextEvent:wxStyledText() |
          wxSysColourChangedEvent:wxSysColourChanged() |
          wxTaskBarIconEvent:wxTaskBarIcon() |
          wxTreeEvent:wxTree() |
          wxUpdateUIEvent:wxUpdateUI() |
          wxWebViewEvent:wxWebView() |
          wxWindowCreateEvent:wxWindowCreate() |
          wxWindowDestroyEvent:wxWindowDestroy().

Like… the whole event buffet. Name your fave, they're all here. 🍓

💜 wx()

wx() :: #wx{}.

🌸 wxEventType()

wxEventType() ::
          wxActivateEvent:wxActivateEventType() |
          wxAuiManagerEvent:wxAuiManagerEventType() |
          wxAuiNotebookEvent:wxAuiNotebookEventType() |
          wxBookCtrlEvent:wxBookCtrlEventType() |
          wxCalendarEvent:wxCalendarEventType() |
          wxChildFocusEvent:wxChildFocusEventType() |
          wxClipboardTextEvent:wxClipboardTextEventType() |
          wxCloseEvent:wxCloseEventType() |
          wxColourPickerEvent:wxColourPickerEventType() |
          wxCommandEvent:wxCommandEventType() |
          wxContextMenuEvent:wxContextMenuEventType() |
          wxDateEvent:wxDateEventType() |
          wxDisplayChangedEvent:wxDisplayChangedEventType() |
          wxDropFilesEvent:wxDropFilesEventType() |
          wxEraseEvent:wxEraseEventType() |
          wxFileDirPickerEvent:wxFileDirPickerEventType() |
          wxFocusEvent:wxFocusEventType() |
          wxFontPickerEvent:wxFontPickerEventType() |
          wxGridEvent:wxGridEventType() |
          wxHelpEvent:wxHelpEventType() |
          wxHtmlLinkEvent:wxHtmlLinkEventType() |
          wxIconizeEvent:wxIconizeEventType() |
          wxIdleEvent:wxIdleEventType() |
          wxInitDialogEvent:wxInitDialogEventType() |
          wxJoystickEvent:wxJoystickEventType() |
          wxKeyEvent:wxKeyEventType() |
          wxListEvent:wxListEventType() |
          wxMaximizeEvent:wxMaximizeEventType() |
          wxMenuEvent:wxMenuEventType() |
          wxMouseCaptureChangedEvent:wxMouseCaptureChangedEventType() |
          wxMouseCaptureLostEvent:wxMouseCaptureLostEventType() |
          wxMouseEvent:wxMouseEventType() |
          wxMoveEvent:wxMoveEventType() |
          wxNavigationKeyEvent:wxNavigationKeyEventType() |
          wxPaintEvent:wxPaintEventType() |
          wxPaletteChangedEvent:wxPaletteChangedEventType() |
          wxQueryNewPaletteEvent:wxQueryNewPaletteEventType() |
          wxSashEvent:wxSashEventType() |
          wxScrollEvent:wxScrollEventType() |
          wxScrollWinEvent:wxScrollWinEventType() |
          wxSetCursorEvent:wxSetCursorEventType() |
          wxShowEvent:wxShowEventType() |
          wxSizeEvent:wxSizeEventType() |
          wxSpinEvent:wxSpinEventType() |
          wxSplitterEvent:wxSplitterEventType() |
          wxStyledTextEvent:wxStyledTextEventType() |
          wxSysColourChangedEvent:wxSysColourChangedEventType() |
          wxTaskBarIconEvent:wxTaskBarIconEventType() |
          wxTreeEvent:wxTreeEventType() |
          wxUpdateUIEvent:wxUpdateUIEventType() |
          wxWebViewEvent:wxWebViewEventType() |
          wxWindowCreateEvent:wxWindowCreateEventType() |
          wxWindowDestroyEvent:wxWindowDestroyEventType().

Every event type has a matching EventType. Chef's kiss. Matched set, slay. 💅

🎀 wxEvtHandler()

wxEvtHandler() :: wx:wx_object().

---

👑 FUNCTIONS 👑

🫶 connect/3

connect(This :: wxEvtHandler(),
             EventType :: wxEventType(),
             [Option]) ->
                ok
                when
                    Option ::
                        {id, integer()} |
                        {lastId, integer()} |
                        {skip, boolean()} |
                        callback |
                        {callback, function()} |
                        {userData, term()}.

This function subscribes to events. It's the whole point bestie, okay, like — you slide in and you subscribe. 🎀

Subscribes to events of type EventType, in the range id, lastId.

The events will be received as messages if no callback is supplied. 💌

✨ Options ✨

• id:{id, integer()} — The identifier (or first of the identifier range) to be associated with this event handler. Default is ?wxID_ANY
• lastid:{lastId,integer()} — The second part of the identifier range. If used 'id' must be set as the starting identifier range. Default is ?wxID_ANY
• skip:{skip,boolean()} — If skip is true further event_handlers will be called. This is not used if the 'callback' option is used. Default is false.
• callback:{callback,function()} — Use a callbackfun(EventRecord::wx(),EventObject::wxObject()) to process the event. Default not specified i.e. a message will be delivered to the process calling this function.
• userData:{userData,term()} — An erlang term that will be sent with the event. Default: [].

🙈 Bestie reminder: {skip,true} taps in more event_handlers, and it does absolutely nothing if you brought a callback. Pick a lane. 💫

---

🦋 disconnect/3

disconnect(This :: wxEvtHandler(),
                 EventType :: wxEventType(),
                 [Option]) ->
                    boolean()
                    when
                        Option ::
                            {id, integer()} |
                            {lastId, integer()} |
                            {callback, function()}.

This function unsubscribes the process or callback fun from the event handler. Yeah. Unsubscribing. It's giving "we need to talk" but make it wholesome. 💔

EventType may be the atom 'null' to match any eventtype. Notice that the options skip and userdata is not used to match the eventhandler.

⚠️ Real talk: those two options don't participate in matching at all. They're just ✨there✨ for the ride. Don't expect them to filter anything.

---

and that's the page, periodt ✨💖

Mwah, ily for reading this far. 🫶 This masterpiece comes to you courtesy of Ericsson AB, plucked straight from the wx 2.6 era — like, vintage but make it iconic. 💅 Lowkey a whole time capsule fr fr. 🎀