X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/bf95a04f16759468ee7af83a7a78019399c648bb..766571a7039fe4428dabe5e2aabcb4055ceb9db9:/docs/latex/wx/tevent.tex diff --git a/docs/latex/wx/tevent.tex b/docs/latex/wx/tevent.tex index 7d746e98de..1e4e37c13c 100644 --- a/docs/latex/wx/tevent.tex +++ b/docs/latex/wx/tevent.tex @@ -2,15 +2,15 @@ Classes: \helpref{wxEvtHandler}{wxevthandler}, \helpref{wxWindow}{wxwindow}, \helpref{wxEvent}{wxevent} -\subsection{Introduction} +\subsection{Introduction}\label{eventintroduction} -Before version 2.0 of wxWindows, events were handled by the application +Before version 2.0 of wxWidgets, events were handled by the application either by supplying callback functions, or by overriding virtual member functions such as {\bf OnSize}. -From wxWindows 2.0, {\it event tables} are used instead, with a few exceptions. +From wxWidgets 2.0, {\it event tables} are used instead, with a few exceptions. -An event table is placed in an implementation file to tell wxWindows how to map +An event table is placed in an implementation file to tell wxWidgets how to map events to member functions. These member functions are not virtual functions, but they are all similar in form: they take a single wxEvent-derived argument, and have a void return type. @@ -84,11 +84,11 @@ connect the events to the handlers dynamically, during run-time. See the \subsection{How events are processed}\label{eventprocessing} -When an event is received from the windowing system, wxWindows calls +When an event is received from the windowing system, wxWidgets calls \helpref{wxEvtHandler::ProcessEvent}{wxevthandlerprocessevent} on the first event handler object belonging to the window generating the event. -It may be noted that wxWindows' event processing system implements something +It may be noted that wxWidgets' event processing system implements something very close to virtual methods in normal C++, i.e. it is possible to alter the behaviour of a class by overriding its event handling functions. In many cases this works even for changing the behaviour of native controls. @@ -113,7 +113,7 @@ void MyTextCtrl::OnChar(wxKeyEvent& event) if ( isalpha( event.KeyCode() ) ) { // key code is within legal range. we call event.Skip() so the - // event can be processed either in the base wxWindows class + // event can be processed either in the base wxWidgets class // or the native control. event.Skip(); @@ -149,7 +149,7 @@ to the parent window's event handler. If this returns true, the function exits. \end{enumerate} {\bf Pay close attention to Step 5.} People often overlook or get -confused by this powerful feature of the wxWindows event processing +confused by this powerful feature of the wxWidgets event processing system. To put it a different way, events set to propagate (\helpref{See: wxEvent::ShouldPropagate}{wxeventshouldpropagate}) (most likely derived either directly or indirectly from wxCommandEvent) @@ -158,7 +158,7 @@ maximal propagation level is reached or an event handler is found that doesn't call \helpref{event.Skip()}{wxeventskip}. Finally, there is another additional complication (which, in fact, simplifies -life of wxWindows programmers significantly): when propagating the command +life of wxWidgets programmers significantly): when propagating the command events upwards to the parent window, the event propagation stops when it reaches the parent dialog, if any. This means that you don't risk to get unexpected events from the dialog controls (which might be left unprocessed by @@ -168,7 +168,7 @@ for this choice is that there are only a few frames in a typical application and their parent-child relation are well understood by the programmer while it may be very difficult, if not impossible, to track down all the dialogs which may be popped up in a complex program (remember that some are created -automatically by wxWindows). If you need to specify a different behaviour for +automatically by wxWidgets). If you need to specify a different behaviour for some reason, you can use \helpref{SetExtraStyle(wxWS\_EX\_BLOCK\_EVENTS)}{wxwindowsetextrastyle} explicitly to prevent the events from being propagated beyond the given window @@ -189,7 +189,7 @@ be the only events you wish to redirect), you may use instead of using the slower run-time type system. As mentioned above, only command events are recursively applied to the parents event -handler in the libary itself. As this quite often causes confusion for users, +handler in the library itself. As this quite often causes confusion for users, here is a list of system events which will NOT get sent to the parent's event handler: \begin{twocollist}\itemsep=0pt @@ -207,10 +207,10 @@ here is a list of system events which will NOT get sent to the parent's event ha \twocolitem{\helpref{wxMoveEvent}{wxmoveevent}}{A move event} \twocolitem{\helpref{wxPaintEvent}{wxpaintevent}}{A paint event} \twocolitem{\helpref{wxQueryLayoutInfoEvent}{wxquerylayoutinfoevent}}{Used to query layout information} +\twocolitem{\helpref{wxSetCursorEvent}{wxsetcursorevent}}{Used for special cursor processing based on current mouse position} \twocolitem{\helpref{wxSizeEvent}{wxsizeevent}}{A size event} \twocolitem{\helpref{wxScrollWinEvent}{wxscrollwinevent}}{A scroll event sent by a scrolled window (not a scroll bar)} \twocolitem{\helpref{wxSysColourChangedEvent}{wxsyscolourchangedevent}}{A system colour change event} -\twocolitem{\helpref{wxUpdateUIEvent}{wxupdateuievent}}{A user interface update event} \end{twocollist} In some cases, it might be desired by the programmer to get a certain number @@ -236,7 +236,7 @@ all events (or any selection of them) to the parent window. % requests, so no extra coding is required to support them in your menus and % toolbars. -\subsection{Pluggable event handlers} +\subsection{Pluggable event handlers}\label{pluggablehandlers} In fact, you don't have to derive a new class from a window class if you don't want to. You can derive a new class from wxEvtHandler instead, @@ -275,7 +275,7 @@ may use the {\tt wxID\_OK} identifier, for example, on any number of dialogs so long as you don't have several within the same dialog. If you pass {\tt wxID\_ANY} to a window constructor, an identifier will be -generated for you automatically by wxWindows. This is useful when you don't +generated for you automatically by wxWidgets. This is useful when you don't care about the exact identifier either because you're not going to process the events from the control being created at all or because you process the events from all controls in one place (in which case you should specify {\tt wxID\_ANY} @@ -355,21 +355,6 @@ you can use identifiers below wxID\_LOWEST. \subsection{Event macros summary}\label{eventmacros} -\wxheading{Generic event table macros} - -\twocolwidtha{8cm}% -\begin{twocollist}\itemsep=0pt -\twocolitem{\windowstyle{EVT\_CUSTOM(event, id, func)}}{Allows you to add a custom event table -entry by specifying the event identifier (such as wxEVT\_SIZE), the window identifier, -and a member function to call.} -\twocolitem{\windowstyle{EVT\_CUSTOM\_RANGE(event, id1, id2, func)}}{The same as EVT\_CUSTOM, -but responds to a range of window identifiers.} -\twocolitem{\windowstyle{EVT\_COMMAND(id, event, func)}}{The same as EVT\_CUSTOM, but -expects a member function with a wxCommandEvent argument.} -\twocolitem{\windowstyle{EVT\_COMMAND\_RANGE(id1, id2, event, func)}}{The same as EVT\_CUSTOM\_RANGE, but -expects a member function with a wxCommandEvent argument.} -\end{twocollist} - \wxheading{Macros listed by event class} The documentation for specific event macros is organised by event class. Please refer @@ -400,6 +385,7 @@ mouse events or all mouse events.} \twocolitem{\helpref{wxPaintEvent}{wxpaintevent}}{The EVT\_PAINT macro is used to handle window paint requests.} \twocolitem{\helpref{wxScrollEvent}{wxscrollevent}}{These macros are used to handle scroll events from \helpref{wxScrollBar}{wxscrollbar}, \helpref{wxSlider}{wxslider},and \helpref{wxSpinButton}{wxspinbutton}.} +\twocolitem{\helpref{wxSetCursorEvent}{wxsetcursorevent}}{The EVT\_SET\_CURSOR macro is used for special cursor processing.} \twocolitem{\helpref{wxSizeEvent}{wxsizeevent}}{The EVT\_SIZE macro is used to handle a window resize.} \twocolitem{\helpref{wxSplitterEvent}{wxsplitterevent}}{The EVT\_SPLITTER\_SASH\_POS\_CHANGED, EVT\_SPLITTER\_UNSPLIT and EVT\_SPLITTER\_DCLICK macros are used to handle the various splitter window events.} @@ -411,3 +397,170 @@ update pseudo-events, which are generated to give the application the chance to toolbars and controls.} \end{twocollist} +\subsection{Custom event summary}\label{customevents} + +\wxheading{General approach} + +Since version 2.2.x of wxWidgets, each event type is identified by ID which +is given to the event type {\it at runtime} which makes it possible to add +new event types to the library or application without risking ID clashes +(two different event types mistakingly getting the same event ID). This +event type ID is stored in a struct of type {\bf const wxEventType}. + +In order to define a new event type, there are principally two choices. +One is to define a entirely new event class (typically deriving from +\helpref{wxEvent}{wxevent} or \helpref{wxCommandEvent}{wxcommandevent}. +The other is to use the existing event classes and give them an new event +type. You'll have to define and declare a new event type using either way, +and this is done using the following macros: + +\begin{verbatim} +// in the header of the source file +DECLARE_EVENT_TYPE(name, value) + +// in the implementation +DEFINE_EVENT_TYPE(name) +\end{verbatim} + +You can ignore the {\it value} parameter of the DECLARE\_EVENT\_TYPE macro +since it used only for backwards compatibility with wxWidgets 2.0.x based +applications where you have to give the event type ID an explicit value. + +\wxheading{Using existing event classes} + +If you just want to use a \helpref{wxCommandEvent}{wxcommandevent} with +a new event type, you can then use one of the generic event table macros +listed below, without having to define a new macro yourself. This also +has the advantage that you won't have to define a new \helpref{wxEvent::Clone()}{wxeventclone} +method for posting events between threads etc. This could look like this +in your code: + +{\small% +\begin{verbatim} +DECLARE_EVENT_TYPE(wxEVT_MY_EVENT, -1) + +DEFINE_EVENT_TYPE(wxEVT_MY_EVENT) + +// user code intercepting the event + +BEGIN_EVENT_TABLE(MyFrame, wxFrame) + EVT_MENU (wxID_EXIT, MyFrame::OnExit) + // .... + EVT_COMMAND (ID_MY_WINDOW, wxEVT_MY_EVENT, MyFrame::OnMyEvent) +END_EVENT_TABLE() + +void MyFrame::OnMyEvent( wxCommandEvent &event ) +{ + // do something + wxString text = event.GetText(); +} + + +// user code sending the event + +void MyWindow::SendEvent() +{ + wxCommandEvent event( wxEVT_MY_EVENT, GetId() ); + event.SetEventObject( this ); + // Give it some contents + event.SetText( wxT("Hallo") ); + // Send it + GetEventHandler()->ProcessEvent( event ); +} +\end{verbatim} +}% + + +\wxheading{Generic event table macros} + +\twocolwidtha{8cm}% +\begin{twocollist}\itemsep=0pt +\twocolitem{\windowstyle{EVT\_CUSTOM(event, id, func)}}{Allows you to add a custom event table +entry by specifying the event identifier (such as wxEVT\_SIZE), the window identifier, +and a member function to call.} +\twocolitem{\windowstyle{EVT\_CUSTOM\_RANGE(event, id1, id2, func)}}{The same as EVT\_CUSTOM, +but responds to a range of window identifiers.} +\twocolitem{\windowstyle{EVT\_COMMAND(id, event, func)}}{The same as EVT\_CUSTOM, but +expects a member function with a wxCommandEvent argument.} +\twocolitem{\windowstyle{EVT\_COMMAND\_RANGE(id1, id2, event, func)}}{The same as EVT\_CUSTOM\_RANGE, but +expects a member function with a wxCommandEvent argument.} +\twocolitem{\windowstyle{EVT\_NOTIFY(id, event, func)}}{The same as EVT\_CUSTOM, but +expects a member function with a wxNotifyEvent argument.} +\twocolitem{\windowstyle{EVT\_NOTIFY\_RANGE(id1, id2, event, func)}}{The same as EVT\_CUSTOM\_RANGE, but +expects a member function with a wxNotifyEvent argument.} +\end{twocollist} + + +\wxheading{Defining your own event class} + +Under certain circumstances, it will be required to define your own event +class e.g. for sending more complex data from one place to another. Apart +from defining your event class, you will also need to define your own +event table macro (which is quite long). Watch out to put in enough +casts to the inherited event function. Here is an example, taken mostly +from the {\it wxPlot} library, which is in the {\it contrib} section of +the wxWidgets sources. + +{\small% +\begin{verbatim} + +// code defining event + +class wxPlotEvent: public wxNotifyEvent +{ +public: + wxPlotEvent( wxEventType commandType = wxEVT_NULL, int id = 0 ); + + // accessors + wxPlotCurve *GetCurve() + { return m_curve; } + + // required for sending with wxPostEvent() + wxEvent* Clone(); + +private: + wxPlotCurve *m_curve; +}; + +DECLARE_EVENT_MACRO( wxEVT_PLOT_ACTION, -1 ) + +typedef void (wxEvtHandler::*wxPlotEventFunction)(wxPlotEvent&); + +#define EVT_PLOT(id, fn) \ + DECLARE_EVENT_TABLE_ENTRY( wxEVT_PLOT_ACTION, id, -1, \ + (wxObjectEventFunction) (wxEventFunction) (wxCommandEventFunction) (wxNotifyEventFunction) \ + wxStaticCastEvent( wxPlotEventFunction, & fn ), (wxObject *) NULL ), + + +// code implementing the event type and the event class + +DEFINE_EVENT_TYPE( wxEVT_PLOT_ACTION ) + +wxPlotEvent::wxPlotEvent( ... + + +// user code intercepting the event + +BEGIN_EVENT_TABLE(MyFrame, wxFrame) + EVT_PLOT (ID_MY_WINDOW, MyFrame::OnPlot) +END_EVENT_TABLE() + +void MyFrame::OnPlot( wxPlotEvent &event ) +{ + wxPlotCurve *curve = event.GetCurve(); +} + + +// user code sending the event + +void MyWindow::SendEvent() +{ + wxPlotEvent event( wxEVT_PLOT_ACTION, GetId() ); + event.SetEventObject( this ); + event.SetCurve( m_curve ); + GetEventHandler()->ProcessEvent( event ); +} + +\end{verbatim} +}% +