///////////////////////////////////////////////////////////////////////////// // Name: interface/wx/event_base.h // Purpose: Documentation of wxEvtHandler, wxEvent, wxIdleEvent and other // non-GUI event-related classes declared in include/wx/event.h // (see interface/wx/event.h for the GUI event classes) // Author: wxWidgets team // RCS-ID: $Id$ // Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// /** The predefined constants for the number of times we propagate event upwards window child-parent chain. */ enum wxEventPropagation { /// don't propagate it at all wxEVENT_PROPAGATE_NONE = 0, /// propagate it until it is processed wxEVENT_PROPAGATE_MAX = INT_MAX }; /** The different categories for a wxEvent; see wxEvent::GetEventCategory. @note They are used as OR-combinable flags by wxEventLoopBase::YieldFor. */ enum wxEventCategory { /** This is the category for those events which are generated to update the appearance of the GUI but which (usually) do not comport data processing, i.e. which do not provide input or output data (e.g. size events, scroll events, etc). They are events NOT directly generated by the user's input devices. */ wxEVT_CATEGORY_UI = 1, /** This category groups those events which are generated directly from the user through input devices like mouse and keyboard and usually result in data to be processed from the application (e.g. mouse clicks, key presses, etc). */ wxEVT_CATEGORY_USER_INPUT = 2, /// This category is for wxSocketEvent wxEVT_CATEGORY_SOCKET = 4, /// This category is for wxTimerEvent wxEVT_CATEGORY_TIMER = 8, /** This category is for any event used to send notifications from the secondary threads to the main one or in general for notifications among different threads (which may or may not be user-generated). See e.g. wxThreadEvent. */ wxEVT_CATEGORY_THREAD = 16, /** This mask is used in wxEventLoopBase::YieldFor to specify that all event categories should be processed. */ wxEVT_CATEGORY_ALL = wxEVT_CATEGORY_UI|wxEVT_CATEGORY_USER_INPUT|wxEVT_CATEGORY_SOCKET| \ wxEVT_CATEGORY_TIMER|wxEVT_CATEGORY_THREAD }; /** @class wxEvent An event is a structure holding information about an event passed to a callback or member function. wxEvent used to be a multipurpose event object, and is an abstract base class for other event classes (see below). For more information about events, see the @ref overview_events overview. @beginWxPerlOnly In wxPerl custom event classes should be derived from @c Wx::PlEvent and @c Wx::PlCommandEvent. @endWxPerlOnly @library{wxbase} @category{events} @header{wx/event.h} @see wxCommandEvent, wxMouseEvent */ class wxEvent : public wxObject { public: /** Constructor. Notice that events are usually created by wxWidgets itself and creating e.g. a wxPaintEvent in your code and sending it to e.g. a wxTextCtrl will not usually affect it at all as native controls have no specific knowledge about wxWidgets events. However you may construct objects of specific types and pass them to wxEvtHandler::ProcessEvent() if you want to create your own custom control and want to process its events in the same manner as the standard ones. Also please notice that the order of parameters in this constructor is different from almost all the derived classes which specify the event type as the first argument. @param id The identifier of the object (window, timer, ...) which generated this event. @param eventType The unique type of event, e.g. @c wxEVT_PAINT, @c wxEVT_SIZE or @c wxEVT_COMMAND_BUTTON_CLICKED. */ wxEvent(int id = 0, wxEventType eventType = wxEVT_NULL); /** Returns a copy of the event. Any event that is posted to the wxWidgets event system for later action (via wxEvtHandler::AddPendingEvent, wxEvtHandler::QueueEvent or wxPostEvent()) must implement this method. All wxWidgets events fully implement this method, but any derived events implemented by the user should also implement this method just in case they (or some event derived from them) are ever posted. All wxWidgets events implement a copy constructor, so the easiest way of implementing the Clone function is to implement a copy constructor for a new event (call it MyEvent) and then define the Clone function like this: @code wxEvent *Clone() const { return new MyEvent(*this); } @endcode */ virtual wxEvent* Clone() const = 0; /** Returns the object (usually a window) associated with the event, if any. */ wxObject* GetEventObject() const; /** Returns the identifier of the given event type, such as @c wxEVT_COMMAND_BUTTON_CLICKED. */ wxEventType GetEventType() const; /** Returns a generic category for this event. wxEvent implementation returns @c wxEVT_CATEGORY_UI by default. This function is used to selectively process events in wxEventLoopBase::YieldFor. */ virtual wxEventCategory GetEventCategory() const; /** Returns the identifier associated with this event, such as a button command id. */ int GetId() const; /** Return the user data associated with a dynamically connected event handler. wxEvtHandler::Connect() and wxEvtHandler::Bind() allow associating optional @c userData pointer with the handler and this method returns the value of this pointer. The returned pointer is owned by wxWidgets and must not be deleted. @since 2.9.5 */ wxObject *GetEventUserData() const; /** Returns @true if the event handler should be skipped, @false otherwise. */ bool GetSkipped() const; /** Gets the timestamp for the event. The timestamp is the time in milliseconds since some fixed moment (not necessarily the standard Unix Epoch, so only differences between the timestamps and not their absolute values usually make sense). @warning wxWidgets returns a non-NULL timestamp only for mouse and key events (see wxMouseEvent and wxKeyEvent). */ long GetTimestamp() const; /** Returns @true if the event is or is derived from wxCommandEvent else it returns @false. @note exists only for optimization purposes. */ bool IsCommandEvent() const; /** Sets the propagation level to the given value (for example returned from an earlier call to wxEvent::StopPropagation). */ void ResumePropagation(int propagationLevel); /** Sets the originating object. */ void SetEventObject(wxObject* object); /** Sets the event type. */ void SetEventType(wxEventType type); /** Sets the identifier associated with this event, such as a button command id. */ void SetId(int id); /** Sets the timestamp for the event. */ void SetTimestamp(long timeStamp = 0); /** Test if this event should be propagated or not, i.e. if the propagation level is currently greater than 0. */ bool ShouldPropagate() const; /** This method can be used inside an event handler to control whether further event handlers bound to this event will be called after the current one returns. Without Skip() (or equivalently if Skip(@false) is used), the event will not be processed any more. If Skip(@true) is called, the event processing system continues searching for a further handler function for this event, even though it has been processed already in the current handler. In general, it is recommended to skip all non-command events to allow the default handling to take place. The command events are, however, normally not skipped as usually a single command such as a button click or menu item selection must only be processed by one handler. */ void Skip(bool skip = true); /** Stop the event from propagating to its parent window. Returns the old propagation level value which may be later passed to ResumePropagation() to allow propagating the event again. */ int StopPropagation(); protected: /** Indicates how many levels the event can propagate. This member is protected and should typically only be set in the constructors of the derived classes. It may be temporarily changed by StopPropagation() and ResumePropagation() and tested with ShouldPropagate(). The initial value is set to either @c wxEVENT_PROPAGATE_NONE (by default) meaning that the event shouldn't be propagated at all or to @c wxEVENT_PROPAGATE_MAX (for command events) meaning that it should be propagated as much as necessary. Any positive number means that the event should be propagated but no more than the given number of times. E.g. the propagation level may be set to 1 to propagate the event to its parent only, but not to its grandparent. */ int m_propagationLevel; }; /** @class wxEvtHandler A class that can handle events from the windowing system. wxWindow is (and therefore all window classes are) derived from this class. When events are received, wxEvtHandler invokes the method listed in the event table using itself as the object. When using multiple inheritance it is imperative that the wxEvtHandler(-derived) class is the first class inherited such that the @c this pointer for the overall object will be identical to the @c this pointer of the wxEvtHandler portion. @library{wxbase} @category{events} @header{wx/event.h} @see @ref overview_events_processing, wxEventBlocker, wxEventLoopBase */ class wxEvtHandler : public wxObject, public wxTrackable { public: /** Constructor. */ wxEvtHandler(); /** Destructor. If the handler is part of a chain, the destructor will unlink itself (see Unlink()). */ virtual ~wxEvtHandler(); /** @name Event queuing and processing */ //@{ /** Queue event for a later processing. This method is similar to ProcessEvent() but while the latter is synchronous, i.e. the event is processed immediately, before the function returns, this one is asynchronous and returns immediately while the event will be processed at some later time (usually during the next event loop iteration). Another important difference is that this method takes ownership of the @a event parameter, i.e. it will delete it itself. This implies that the event should be allocated on the heap and that the pointer can't be used any more after the function returns (as it can be deleted at any moment). QueueEvent() can be used for inter-thread communication from the worker threads to the main thread, it is safe in the sense that it uses locking internally and avoids the problem mentioned in AddPendingEvent() documentation by ensuring that the @a event object is not used by the calling thread any more. Care should still be taken to avoid that some fields of this object are used by it, notably any wxString members of the event object must not be shallow copies of another wxString object as this would result in them still using the same string buffer behind the scenes. For example: @code void FunctionInAWorkerThread(const wxString& str) { wxCommandEvent* evt = new wxCommandEvent; // NOT evt->SetString(str) as this would be a shallow copy evt->SetString(str.c_str()); // make a deep copy wxTheApp->QueueEvent( evt ); } @endcode Note that you can use wxThreadEvent instead of wxCommandEvent to avoid this problem: @code void FunctionInAWorkerThread(const wxString& str) { wxThreadEvent evt; evt->SetString(str); // wxThreadEvent::Clone() makes sure that the internal wxString // member is not shared by other wxString instances: wxTheApp->QueueEvent( evt.Clone() ); } @endcode Finally notice that this method automatically wakes up the event loop if it is currently idle by calling ::wxWakeUpIdle() so there is no need to do it manually when using it. @since 2.9.0 @param event A heap-allocated event to be queued, QueueEvent() takes ownership of it. This parameter shouldn't be @c NULL. */ virtual void QueueEvent(wxEvent *event); /** Post an event to be processed later. This function is similar to QueueEvent() but can't be used to post events from worker threads for the event objects with wxString fields (i.e. in practice most of them) because of an unsafe use of the same wxString object which happens because the wxString field in the original @a event object and its copy made internally by this function share the same string buffer internally. Use QueueEvent() to avoid this. A copy of @a event is made by the function, so the original can be deleted as soon as function returns (it is common that the original is created on the stack). This requires that the wxEvent::Clone() method be implemented by event so that it can be duplicated and stored until it gets processed. @param event Event to add to the pending events queue. */ virtual void AddPendingEvent(const wxEvent& event); /** Asynchronously call the given method. Calling this function on an object schedules an asynchronous call to the method specified as CallAfter() argument at a (slightly) later time. This is useful when processing some events as certain actions typically can't be performed inside their handlers, e.g. you shouldn't show a modal dialog from a mouse click event handler as this would break the mouse capture state -- but you can call a method showing this message dialog after the current event handler completes. The method being called must be the method of the object on which CallAfter() itself is called. Notice that it is safe to use CallAfter() from other, non-GUI, threads, but that the method will be always called in the main, GUI, thread context. Example of use: @code class MyFrame : public wxFrame { void OnClick(wxMouseEvent& event) { CallAfter(&MyFrame::ShowPosition, event.GetPosition()); } void ShowPosition(const wxPoint& pos) { if ( wxMessageBox( wxString::Format("Perform click at (%d, %d)?", pos.x, pos.y), "", wxYES_NO) == wxYES ) { ... do take this click into account ... } } }; @endcode @param method The method to call. @param x1 The (optional) first parameter to pass to the method. @param x2 The (optional) second parameter to pass to the method. Note that currently only up to 2 arguments can be passed. @note This method is not available with Visual C++ 6 which doesn't have the required support for C++ templates to implement it. @since 2.9.5 */ template void CallAfter(void (T::*method)(T1, ...), T1 x1, ...); /** Processes an event, searching event tables and calling zero or more suitable event handler function(s). Normally, your application would not call this function: it is called in the wxWidgets implementation to dispatch incoming user interface events to the framework (and application). However, you might need to call it if implementing new functionality (such as a new control) where you define new event types, as opposed to allowing the user to override virtual functions. Notice that you don't usually need to override ProcessEvent() to customize the event handling, overriding the specially provided TryBefore() and TryAfter() functions is usually enough. For example, wxMDIParentFrame may override TryBefore() to ensure that the menu events are processed in the active child frame before being processed in the parent frame itself. The normal order of event table searching is as follows: -# wxApp::FilterEvent() is called. If it returns anything but @c -1 (default) the processing stops here. -# TryBefore() is called (this is where wxValidator are taken into account for wxWindow objects). If this returns @true, the function exits. -# If the object is disabled (via a call to wxEvtHandler::SetEvtHandlerEnabled) the function skips to step (7). -# Dynamic event table of the handlers bound using Bind<>() is searched. If a handler is found, it is executed and the function returns @true unless the handler used wxEvent::Skip() to indicate that it didn't handle the event in which case the search continues. -# Static events table of the handlers bound using event table macros is searched for this event handler. If this fails, the base class event table is tried, and so on until no more tables exist or an appropriate function was found. If a handler is found, the same logic as in the previous step applies. -# The search is applied down the entire chain of event handlers (usually the chain has a length of one). This chain can be formed using wxEvtHandler::SetNextHandler(): @image html overview_events_chain.png (referring to the image, if @c A->ProcessEvent is called and it doesn't handle the event, @c B->ProcessEvent will be called and so on...). Note that in the case of wxWindow you can build a stack of event handlers (see wxWindow::PushEventHandler() for more info). If any of the handlers of the chain return @true, the function exits. -# TryAfter() is called: for the wxWindow object this may propagate the event to the window parent (recursively). If the event is still not processed, ProcessEvent() on wxTheApp object is called as the last step. Notice that steps (2)-(6) are performed in ProcessEventLocally() which is called by this function. @param event Event to process. @return @true if a suitable event handler function was found and executed, and the function did not call wxEvent::Skip. @see SearchEventTable() */ virtual bool ProcessEvent(wxEvent& event); /** Try to process the event in this handler and all those chained to it. As explained in ProcessEvent() documentation, the event handlers may be chained in a doubly-linked list. This function tries to process the event in this handler (including performing any pre-processing done in TryBefore(), e.g. applying validators) and all those following it in the chain until the event is processed or the chain is exhausted. This function is called from ProcessEvent() and, in turn, calls TryBefore() and TryAfter(). It is not virtual and so cannot be overridden but can, and should, be called to forward an event to another handler instead of ProcessEvent() which would result in a duplicate call to TryAfter(), e.g. resulting in all unprocessed events being sent to the application object multiple times. @since 2.9.1 @param event Event to process. @return @true if this handler of one of those chained to it processed the event. */ bool ProcessEventLocally(wxEvent& event); /** Processes an event by calling ProcessEvent() and handles any exceptions that occur in the process. If an exception is thrown in event handler, wxApp::OnExceptionInMainLoop is called. @param event Event to process. @return @true if the event was processed, @false if no handler was found or an exception was thrown. @see wxWindow::HandleWindowEvent */ bool SafelyProcessEvent(wxEvent& event); /** Processes the pending events previously queued using QueueEvent() or AddPendingEvent(); you must call this function only if you are sure there are pending events for this handler, otherwise a @c wxCHECK will fail. The real processing still happens in ProcessEvent() which is called by this function. Note that this function needs a valid application object (see wxAppConsole::GetInstance()) because wxApp holds the list of the event handlers with pending events and this function manipulates that list. */ void ProcessPendingEvents(); /** Deletes all events queued on this event handler using QueueEvent() or AddPendingEvent(). Use with care because the events which are deleted are (obviously) not processed and this may have unwanted consequences (e.g. user actions events will be lost). */ void DeletePendingEvents(); /** Searches the event table, executing an event handler function if an appropriate one is found. @param table Event table to be searched. @param event Event to be matched against an event table entry. @return @true if a suitable event handler function was found and executed, and the function did not call wxEvent::Skip. @remarks This function looks through the object's event table and tries to find an entry that will match the event. An entry will match if: @li The event type matches, and @li the identifier or identifier range matches, or the event table entry's identifier is zero. If a suitable function is called but calls wxEvent::Skip, this function will fail, and searching will continue. @todo this function in the header is listed as an "implementation only" function; are we sure we want to document it? @see ProcessEvent() */ virtual bool SearchEventTable(wxEventTable& table, wxEvent& event); //@} /** @name Connecting and disconnecting */ //@{ /** Connects the given function dynamically with the event handler, id and event type. Notice that Bind() provides a more flexible and safer way to do the same thing as Connect(), please use it in any new code -- while Connect() is not formally deprecated due to its existing widespread usage, it has no advantages compared to Bind(). This is an alternative to the use of static event tables. It is more flexible as it allows to connect events generated by some object to an event handler defined in a different object of a different class (which is impossible to do directly with the event tables -- the events can be only handled in another object if they are propagated upwards to it). Do make sure to specify the correct @a eventSink when connecting to an event of a different object. See @ref overview_events_bind for more detailed explanation of this function and the @ref page_samples_event sample for usage examples. This specific overload allows you to connect an event handler to a @e range of @e source IDs. Do not confuse @e source IDs with event @e types: source IDs identify the event generator objects (typically wxMenuItem or wxWindow objects) while the event @e type identify which type of events should be handled by the given @e function (an event generator object may generate many different types of events!). @param id The first ID of the identifier range to be associated with the event handler function. @param lastId The last ID of the identifier range to be associated with the event handler function. @param eventType The event type to be associated with this event handler. @param function The event handler function. Note that this function should be explicitly converted to the correct type which can be done using a macro called @c wxFooEventHandler for the handler for any @c wxFooEvent. @param userData Optional data to be associated with the event table entry. wxWidgets will take ownership of this pointer, i.e. it will be destroyed when the event handler is disconnected or at the program termination. This pointer can be retrieved using wxEvent::GetEventUserData() later. @param eventSink Object whose member function should be called. It must be specified when connecting an event generated by one object to a member function of a different object. If it is omitted, @c this is used. @beginWxPerlOnly In wxPerl this function takes 4 arguments: @a id, @a lastid, @a type, @a method; if @a method is undef, the handler is disconnected.} @endWxPerlOnly @see Bind<>() */ void Connect(int id, int lastId, wxEventType eventType, wxObjectEventFunction function, wxObject* userData = NULL, wxEvtHandler* eventSink = NULL); /** See the Connect(int, int, wxEventType, wxObjectEventFunction, wxObject*, wxEvtHandler*) overload for more info. This overload can be used to attach an event handler to a single source ID: Example: @code frame->Connect( wxID_EXIT, wxEVT_COMMAND_MENU_SELECTED, wxCommandEventHandler(MyFrame::OnQuit) ); @endcode @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ void Connect(int id, wxEventType eventType, wxObjectEventFunction function, wxObject* userData = NULL, wxEvtHandler* eventSink = NULL); /** See the Connect(int, int, wxEventType, wxObjectEventFunction, wxObject*, wxEvtHandler*) overload for more info. This overload will connect the given event handler so that regardless of the ID of the event source, the handler will be called. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ void Connect(wxEventType eventType, wxObjectEventFunction function, wxObject* userData = NULL, wxEvtHandler* eventSink = NULL); /** Disconnects the given function dynamically from the event handler, using the specified parameters as search criteria and returning @true if a matching function has been found and removed. This method can only disconnect functions which have been added using the Connect() method. There is no way to disconnect functions connected using the (static) event tables. @param eventType The event type associated with this event handler. @param function The event handler function. @param userData Data associated with the event table entry. @param eventSink Object whose member function should be called. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ bool Disconnect(wxEventType eventType, wxObjectEventFunction function, wxObject* userData = NULL, wxEvtHandler* eventSink = NULL); /** See the Disconnect(wxEventType, wxObjectEventFunction, wxObject*, wxEvtHandler*) overload for more info. This overload takes the additional @a id parameter. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ bool Disconnect(int id = wxID_ANY, wxEventType eventType = wxEVT_NULL, wxObjectEventFunction function = NULL, wxObject* userData = NULL, wxEvtHandler* eventSink = NULL); /** See the Disconnect(wxEventType, wxObjectEventFunction, wxObject*, wxEvtHandler*) overload for more info. This overload takes an additional range of source IDs. @beginWxPerlOnly In wxPerl this function takes 3 arguments: @a id, @a lastid, @a type. @endWxPerlOnly */ bool Disconnect(int id, int lastId, wxEventType eventType, wxObjectEventFunction function = NULL, wxObject* userData = NULL, wxEvtHandler* eventSink = NULL); //@} /** @name Binding and Unbinding */ //@{ /** Binds the given function, functor or method dynamically with the event. This offers basically the same functionality as Connect(), but it is more flexible as it also allows you to use ordinary functions and arbitrary functors as event handlers. It is also less restrictive then Connect() because you can use an arbitrary method as an event handler, whereas Connect() requires a wxEvtHandler derived handler. See @ref overview_events_bind for more detailed explanation of this function and the @ref page_samples_event sample for usage examples. @param eventType The event type to be associated with this event handler. @param functor The event handler functor. This can be an ordinary function but also an arbitrary functor like boost::function<>. @param id The first ID of the identifier range to be associated with the event handler. @param lastId The last ID of the identifier range to be associated with the event handler. @param userData Optional data to be associated with the event table entry. wxWidgets will take ownership of this pointer, i.e. it will be destroyed when the event handler is disconnected or at the program termination. This pointer can be retrieved using wxEvent::GetEventUserData() later. @see @ref overview_cpp_rtti_disabled @since 2.9.0 */ template void Bind(const EventTag& eventType, Functor functor, int id = wxID_ANY, int lastId = wxID_ANY, wxObject *userData = NULL); /** See the Bind<>(const EventTag&, Functor, int, int, wxObject*) overload for more info. This overload will bind the given method as the event handler. @param eventType The event type to be associated with this event handler. @param method The event handler method. This can be an arbitrary method (doesn't need to be from a wxEvtHandler derived class). @param handler Object whose method should be called. It must always be specified so it can be checked at compile time whether the given method is an actual member of the given handler. @param id The first ID of the identifier range to be associated with the event handler. @param lastId The last ID of the identifier range to be associated with the event handler. @param userData Optional data to be associated with the event table entry. wxWidgets will take ownership of this pointer, i.e. it will be destroyed when the event handler is disconnected or at the program termination. This pointer can be retrieved using wxEvent::GetEventUserData() later. @see @ref overview_cpp_rtti_disabled @since 2.9.0 */ template void Bind(const EventTag &eventType, void (Class::*method)(EventArg &), EventHandler *handler, int id = wxID_ANY, int lastId = wxID_ANY, wxObject *userData = NULL); /** Unbinds the given function, functor or method dynamically from the event handler, using the specified parameters as search criteria and returning @true if a matching function has been found and removed. This method can only unbind functions, functors or methods which have been added using the Bind<>() method. There is no way to unbind functions bound using the (static) event tables. @param eventType The event type associated with this event handler. @param functor The event handler functor. This can be an ordinary function but also an arbitrary functor like boost::function<>. @param id The first ID of the identifier range associated with the event handler. @param lastId The last ID of the identifier range associated with the event handler. @param userData Data associated with the event table entry. @see @ref overview_cpp_rtti_disabled @since 2.9.0 */ template bool Unbind(const EventTag& eventType, Functor functor, int id = wxID_ANY, int lastId = wxID_ANY, wxObject *userData = NULL); /** See the Unbind<>(const EventTag&, Functor, int, int, wxObject*) overload for more info. This overload unbinds the given method from the event.. @param eventType The event type associated with this event handler. @param method The event handler method associated with this event. @param handler Object whose method was called. @param id The first ID of the identifier range associated with the event handler. @param lastId The last ID of the identifier range associated with the event handler. @param userData Data associated with the event table entry. @see @ref overview_cpp_rtti_disabled @since 2.9.0 */ template bool Unbind(const EventTag &eventType, void (Class::*method)(EventArg&), EventHandler *handler, int id = wxID_ANY, int lastId = wxID_ANY, wxObject *userData = NULL ); //@} /** @name User-supplied data */ //@{ /** Returns user-supplied client data. @remarks Normally, any extra data the programmer wishes to associate with the object should be made available by deriving a new class with new data members. @see SetClientData() */ void* GetClientData() const; /** Returns a pointer to the user-supplied client data object. @see SetClientObject(), wxClientData */ wxClientData* GetClientObject() const; /** Sets user-supplied client data. @param data Data to be associated with the event handler. @remarks Normally, any extra data the programmer wishes to associate with the object should be made available by deriving a new class with new data members. You must not call this method and SetClientObject on the same class - only one of them. @see GetClientData() */ void SetClientData(void* data); /** Set the client data object. Any previous object will be deleted. @see GetClientObject(), wxClientData */ void SetClientObject(wxClientData* data); //@} /** @name Event handler chaining wxEvtHandler can be arranged in a double-linked list of handlers which is automatically iterated by ProcessEvent() if needed. */ //@{ /** Returns @true if the event handler is enabled, @false otherwise. @see SetEvtHandlerEnabled() */ bool GetEvtHandlerEnabled() const; /** Returns the pointer to the next handler in the chain. @see SetNextHandler(), GetPreviousHandler(), SetPreviousHandler(), wxWindow::PushEventHandler, wxWindow::PopEventHandler */ wxEvtHandler* GetNextHandler() const; /** Returns the pointer to the previous handler in the chain. @see SetPreviousHandler(), GetNextHandler(), SetNextHandler(), wxWindow::PushEventHandler, wxWindow::PopEventHandler */ wxEvtHandler* GetPreviousHandler() const; /** Enables or disables the event handler. @param enabled @true if the event handler is to be enabled, @false if it is to be disabled. @remarks You can use this function to avoid having to remove the event handler from the chain, for example when implementing a dialog editor and changing from edit to test mode. @see GetEvtHandlerEnabled() */ void SetEvtHandlerEnabled(bool enabled); /** Sets the pointer to the next handler. @remarks See ProcessEvent() for more info about how the chains of event handlers are internally used. Also remember that wxEvtHandler uses double-linked lists and thus if you use this function, you should also call SetPreviousHandler() on the argument passed to this function: @code handlerA->SetNextHandler(handlerB); handlerB->SetPreviousHandler(handlerA); @endcode @param handler The event handler to be set as the next handler. Cannot be @NULL. @see @ref overview_events_processing */ virtual void SetNextHandler(wxEvtHandler* handler); /** Sets the pointer to the previous handler. All remarks about SetNextHandler() apply to this function as well. @param handler The event handler to be set as the previous handler. Cannot be @NULL. @see @ref overview_events_processing */ virtual void SetPreviousHandler(wxEvtHandler* handler); /** Unlinks this event handler from the chain it's part of (if any); then links the "previous" event handler to the "next" one (so that the chain won't be interrupted). E.g. if before calling Unlink() you have the following chain: @image html evthandler_unlink_before.png then after calling @c B->Unlink() you'll have: @image html evthandler_unlink_after.png @since 2.9.0 */ void Unlink(); /** Returns @true if the next and the previous handler pointers of this event handler instance are @NULL. @since 2.9.0 @see SetPreviousHandler(), SetNextHandler() */ bool IsUnlinked() const; //@} /** @name Global event filters. Methods for working with the global list of event filters. Event filters can be defined to pre-process all the events that happen in an application, see wxEventFilter documentation for more information. */ //@{ /** Add an event filter whose FilterEvent() method will be called for each and every event processed by wxWidgets. The filters are called in LIFO order and wxApp is registered as an event filter by default. The pointer must remain valid until it's removed with RemoveFilter() and is not deleted by wxEvtHandler. @since 2.9.3 */ static void AddFilter(wxEventFilter* filter); /** Remove a filter previously installed with AddFilter(). It's an error to remove a filter that hadn't been previously added or was already removed. @since 2.9.3 */ static void RemoveFilter(wxEventFilter* filter); //@} protected: /** Method called by ProcessEvent() before examining this object event tables. This method can be overridden to hook into the event processing logic as early as possible. You should usually call the base class version when overriding this method, even if wxEvtHandler itself does nothing here, some derived classes do use this method, e.g. wxWindow implements support for wxValidator in it. Example: @code class MyClass : public BaseClass // inheriting from wxEvtHandler { ... protected: virtual bool TryBefore(wxEvent& event) { if ( MyPreProcess(event) ) return true; return BaseClass::TryBefore(event); } }; @endcode @see ProcessEvent() */ virtual bool TryBefore(wxEvent& event); /** Method called by ProcessEvent() as last resort. This method can be overridden to implement post-processing for the events which were not processed anywhere else. The base class version handles forwarding the unprocessed events to wxApp at wxEvtHandler level and propagating them upwards the window child-parent chain at wxWindow level and so should usually be called when overriding this method: @code class MyClass : public BaseClass // inheriting from wxEvtHandler { ... protected: virtual bool TryAfter(wxEvent& event) { if ( BaseClass::TryAfter(event) ) return true; return MyPostProcess(event); } }; @endcode @see ProcessEvent() */ virtual bool TryAfter(wxEvent& event); }; /** See wxIdleEvent::SetMode() for more info. */ enum wxIdleMode { /** Send idle events to all windows */ wxIDLE_PROCESS_ALL, /** Send idle events to windows that have the wxWS_EX_PROCESS_IDLE flag specified */ wxIDLE_PROCESS_SPECIFIED }; /** @class wxIdleEvent This class is used for idle events, which are generated when the system becomes idle. Note that, unless you do something specifically, the idle events are not sent if the system remains idle once it has become it, e.g. only a single idle event will be generated until something else resulting in more normal events happens and only then is the next idle event sent again. If you need to ensure a continuous stream of idle events, you can either use wxIdleEvent::RequestMore method in your handler or call wxWakeUpIdle() periodically (for example from a timer event handler), but note that both of these approaches (and especially the first one) increase the system load and so should be avoided if possible. By default, idle events are sent to all windows, including even the hidden ones because they may be shown if some condition is met from their @c wxEVT_IDLE (or related @c wxEVT_UPDATE_UI) handler. The children of hidden windows do not receive idle events however as they can't change their state in any way noticeable by the user. Finally, the global wxApp object also receives these events, as usual, so it can be used for any global idle time processing. If sending idle events to all windows is causing a significant overhead in your application, you can call wxIdleEvent::SetMode with the value wxIDLE_PROCESS_SPECIFIED, and set the wxWS_EX_PROCESS_IDLE extra window style for every window which should receive idle events, all the other ones will not receive them in this case. @beginEventTable{wxIdleEvent} @event{EVT_IDLE(func)} Process a @c wxEVT_IDLE event. @endEventTable @library{wxbase} @category{events} @header{wx/event.h} @section sec_delayed_action Delayed Action Mechanism wxIdleEvent can be used to perform some action "at slightly later time". This can be necessary in several circumstances when, for whatever reason, something can't be done in the current event handler. For example, if a mouse event handler is called with the mouse button pressed, the mouse can be currently captured and some operations with it -- notably capturing it again -- might be impossible or lead to undesirable results. If you still want to capture it, you can do it from @c wxEVT_IDLE handler when it is called the next time instead of doing it immediately. This can be achieved in two different ways: when using static event tables, you will need a flag indicating to the (always connected) idle event handler whether the desired action should be performed. The originally called handler would then set it to indicate that it should indeed be done and the idle handler itself would reset it to prevent it from doing the same action again. Using dynamically connected event handlers things are even simpler as the original event handler can simply wxEvtHandler::Connect() or wxEvtHandler::Bind() the idle event handler which would only be executed then and could wxEvtHandler::Disconnect() or wxEvtHandler::Unbind() itself. @see @ref overview_events, wxUpdateUIEvent, wxWindow::OnInternalIdle */ class wxIdleEvent : public wxEvent { public: /** Constructor. */ wxIdleEvent(); /** Static function returning a value specifying how wxWidgets will send idle events: to all windows, or only to those which specify that they will process the events. @see SetMode(). */ static wxIdleMode GetMode(); /** Returns @true if the OnIdle function processing this event requested more processing time. @see RequestMore() */ bool MoreRequested() const; /** Tells wxWidgets that more processing is required. This function can be called by an OnIdle handler for a window or window event handler to indicate that wxApp::OnIdle should forward the OnIdle event once more to the application windows. If no window calls this function during OnIdle, then the application will remain in a passive event loop (not calling OnIdle) until a new event is posted to the application by the windowing system. @see MoreRequested() */ void RequestMore(bool needMore = true); /** Static function for specifying how wxWidgets will send idle events: to all windows, or only to those which specify that they will process the events. @param mode Can be one of the ::wxIdleMode values. The default is wxIDLE_PROCESS_ALL. */ static void SetMode(wxIdleMode mode); }; // ============================================================================ // Global functions/macros // ============================================================================ /** @addtogroup group_funcmacro_events */ //@{ /** A value uniquely identifying the type of the event. The values of this type should only be created using wxNewEventType(). See the macro DEFINE_EVENT_TYPE() for more info. @see @ref overview_events_introduction */ typedef int wxEventType; /** A special event type usually used to indicate that some wxEvent has yet no type assigned. */ wxEventType wxEVT_NULL; wxEventType wxEVT_ANY; /** Generates a new unique event type. Usually this function is only used by wxDEFINE_EVENT() and not called directly. */ wxEventType wxNewEventType(); /** Define a new event type associated with the specified event class. This macro defines a new unique event type @a name associated with the event class @a cls. For example: @code wxDEFINE_EVENT(MY_COMMAND_EVENT, wxCommandEvent); class MyCustomEvent : public wxEvent { ... }; wxDEFINE_EVENT(MY_CUSTOM_EVENT, MyCustomEvent); @endcode @see wxDECLARE_EVENT(), @ref overview_events_custom */ #define wxDEFINE_EVENT(name, cls) \ const wxEventTypeTag< cls > name(wxNewEventType()) /** Declares a custom event type. This macro declares a variable called @a name which must be defined elsewhere using wxDEFINE_EVENT(). The class @a cls must be the wxEvent-derived class associated with the events of this type and its full declaration must be visible from the point of use of this macro. For example: @code wxDECLARE_EVENT(MY_COMMAND_EVENT, wxCommandEvent); class MyCustomEvent : public wxEvent { ... }; wxDECLARE_EVENT(MY_CUSTOM_EVENT, MyCustomEvent); @endcode */ #define wxDECLARE_EVENT(name, cls) \ wxDECLARE_EXPORTED_EVENT(wxEMPTY_PARAMETER_VALUE, name, cls) /** Variant of wxDECLARE_EVENT() used for event types defined inside a shared library. This is mostly used by wxWidgets internally, e.g. @code wxDECLARE_EXPORTED_EVENT(WXDLLIMPEXP_CORE, wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEvent) @endcode */ #define wxDECLARE_EXPORTED_EVENT( expdecl, name, cls ) \ extern const expdecl wxEventTypeTag< cls > name; /** Helper macro for definition of custom event table macros. This macro must only be used if wxEVENTS_COMPATIBILITY_2_8 is 1, otherwise it is better and more clear to just use the address of the function directly as this is all this macro does in this case. However it needs to explicitly cast @a func to @a functype, which is the type of wxEvtHandler member function taking the custom event argument when wxEVENTS_COMPATIBILITY_2_8 is 0. See wx__DECLARE_EVT0 for an example of use. @see @ref overview_events_custom_ownclass */ #define wxEVENT_HANDLER_CAST(functype, func) (&func) /** This macro is used to define event table macros for handling custom events. Example of use: @code class MyEvent : public wxEvent { ... }; // note that this is not necessary unless using old compilers: for the // reasonably new ones just use &func instead of MyEventHandler(func) typedef void (wxEvtHandler::*MyEventFunction)(MyEvent&); #define MyEventHandler(func) wxEVENT_HANDLER_CAST(MyEventFunction, func) wxDEFINE_EVENT(MY_EVENT_TYPE, MyEvent); #define EVT_MY(id, func) \ wx__DECLARE_EVT1(MY_EVENT_TYPE, id, MyEventHandler(func)) ... wxBEGIN_EVENT_TABLE(MyFrame, wxFrame) EVT_MY(wxID_ANY, MyFrame::OnMyEvent) wxEND_EVENT_TABLE() @endcode @param evt The event type to handle. @param id The identifier of events to handle. @param fn The event handler method. */ #define wx__DECLARE_EVT1(evt, id, fn) \ wx__DECLARE_EVT2(evt, id, wxID_ANY, fn) /** Generalized version of the wx__DECLARE_EVT1() macro taking a range of IDs instead of a single one. Argument @a id1 is the first identifier of the range, @a id2 is the second identifier of the range. */ #define wx__DECLARE_EVT2(evt, id1, id2, fn) \ DECLARE_EVENT_TABLE_ENTRY(evt, id1, id2, fn, NULL), /** Simplified version of the wx__DECLARE_EVT1() macro, to be used when the event type must be handled regardless of the ID associated with the specific event instances. */ #define wx__DECLARE_EVT0(evt, fn) \ wx__DECLARE_EVT1(evt, wxID_ANY, fn) /** Use this macro inside a class declaration to declare a @e static event table for that class. In the implementation file you'll need to use the wxBEGIN_EVENT_TABLE() and the wxEND_EVENT_TABLE() macros, plus some additional @c EVT_xxx macro to capture events. Note that this macro requires a final semicolon. @see @ref overview_events_eventtables */ #define wxDECLARE_EVENT_TABLE() /** Use this macro in a source file to start listing @e static event handlers for a specific class. Use wxEND_EVENT_TABLE() to terminate the event-declaration block. @see @ref overview_events_eventtables */ #define wxBEGIN_EVENT_TABLE(theClass, baseClass) /** Use this macro in a source file to end listing @e static event handlers for a specific class. Use wxBEGIN_EVENT_TABLE() to start the event-declaration block. @see @ref overview_events_eventtables */ #define wxEND_EVENT_TABLE() /** In a GUI application, this function posts @a event to the specified @e dest object using wxEvtHandler::AddPendingEvent(). Otherwise, it dispatches @a event immediately using wxEvtHandler::ProcessEvent(). See the respective documentation for details (and caveats). Because of limitation of wxEvtHandler::AddPendingEvent() this function is not thread-safe for event objects having wxString fields, use wxQueueEvent() instead. @header{wx/event.h} */ void wxPostEvent(wxEvtHandler* dest, const wxEvent& event); /** Queue an event for processing on the given object. This is a wrapper around wxEvtHandler::QueueEvent(), see its documentation for more details. @header{wx/event.h} @param dest The object to queue the event on, can't be @c NULL. @param event The heap-allocated and non-@c NULL event to queue, the function takes ownership of it. */ void wxQueueEvent(wxEvtHandler* dest, wxEvent *event); //@}