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name wxThreadEvent and YieldFor in wxProgressDialog and in thread overview; update the sample code to use new event macros; minor other changes

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59002 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Francesco Montorsi 2009-02-18 19:32:00 +00:00
parent c4021a7920
commit 3a5677401f
5 changed files with 63 additions and 45 deletions
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30
docs/doxygen/overviews/eventhandling.h
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@ -441,32 +441,10 @@ or unset this flag for the dialogs that have it on by default.
Typically events that deal with a window as a window (size, motion,
paint, mouse, keyboard, etc.) are sent only to the window. Events
that have a higher level of meaning or are generated by the window
itself, (button click, menu select, tree expand, etc.) are command
itself (button click, menu select, tree expand, etc.) are command
events and are sent up to the parent to see if it is interested in the event.
As mentioned above, only command events are recursively applied to the parents
event handler in the library itself. As this quite often causes confusion for
users, here is a list of system events that will @em not get sent to the
parent's event handler:
@li wxEvent: The event base class
@li wxActivateEvent: A window or application activation event
@li wxCloseEvent: A close window or end session event
@li wxEraseEvent: An erase background event
@li wxFocusEvent: A window focus event
@li wxKeyEvent: A keypress event
@li wxIdleEvent: An idle event
@li wxInitDialogEvent: A dialog initialisation event
@li wxJoystickEvent: A joystick event
@li wxMenuEvent: A menu event
@li wxMouseEvent: A mouse event
@li wxMoveEvent: A move event
@li wxPaintEvent: A paint event
@li wxQueryLayoutInfoEvent: Used to query layout information
@li wxSetCursorEvent: Used for special cursor processing based on current mouse position
@li wxSizeEvent: A size event
@li wxScrollWinEvent: A scroll event sent by a scrolled window (not a scroll bar)
@li wxSysColourChangedEvent: A system colour change event
More precisely, as said above, all event classes @b not deriving from wxCommandEvent
(see the wxEvent inheritance map) do @b not propagate upward.
In some cases, it might be desired by the programmer to get a certain number
of system events in a parent window, for example all key events sent to, but not
@ -763,7 +741,7 @@ your identifiers don't conflict accidentally.
@subsection overview_events_macros Event Handling Summary
@subsection overview_events_list List of wxWidgets events
For the full list of event classes, please see the
@ref group_class_events "event classes group page".

26
docs/doxygen/overviews/thread.h
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@ -13,10 +13,13 @@
/**
@page overview_thread Multithreading
@page overview_thread Multithreading Overview
Classes: wxThread, wxThreadHelper, wxMutex, wxCriticalSection, wxCondition, wxSemaphore
@section overview_thread_intro When to use multiple threads
wxWidgets provides a complete set of classes encapsulating objects necessary in
multithreaded (MT) programs: the wxThread class itself and different
synchronization objects: mutexes (see wxMutex) and critical sections (see
@ -45,13 +48,17 @@ two possible implementation choices:
- use wxIdleEvent (e.g. to perform a long calculation while updating a progress dialog)
- do everything at once but call wxWindow::Update() or wxApp::YieldFor(wxEVT_CATEGORY_UI)
periodically to update the screen.
If instead you choose to use threads in your application, please read also
the following sections of this overview.
If instead you choose to use threads in your application, it is strongly recommended
@section overview_thread_notes Important notes for multithreaded applications
When writing a multi-threaded application, it is strongly recommended
that <b>no secondary threads call GUI functions</b>.
The design which uses one GUI thread and several worker threads which communicate
with the main one using @b events is much more robust and will undoubtedly save you
countless problems (example: under Win32 a thread can only access GDI objects such
as pens, brushes, c created by itself and not by the other threads).
as pens, brushes, device contexts created by itself and not by the other threads).
For communication between secondary threads and the main thread, you may use
wxEvtHandler::QueueEvent or its short version ::wxQueueEvent. These functions
@ -62,6 +69,19 @@ synchronization classes to implement the solution which suits your needs
yourself. In particular, please note that it is not enough to derive
your class from wxThread and wxEvtHandler to send messages to it: in fact, this
does not work at all.
You're instead encouraged to use wxThreadHelper as it greatly simplifies the
communication and the sharing of resources.
You should also look at the wxThread docs for important notes about secondary
threads and their deletion.
Last, remember that if wxEventLoopBase::YieldFor() is used directly or indirectly
(e.g. through wxProgressDialog) in your code, then you may have both re-entrancy
problems and also problems caused by the processing of events out of order.
To resolve the last problem wxThreadEvent can be used: thanks to its implementation
of the wxThreadEvent::GetEventCategory function wxThreadEvent classes in fact
do not get processed by wxEventLoopBase::YieldFor() unless you specify the
@c wxEVT_CATEGORY_THREAD flag.
See also the @sample{thread} for a sample showing some simple interactions
between the main and secondary threads.

12
interface/wx/event.h
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@ -147,6 +147,7 @@ public:
/**
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.
*/
@ -2030,6 +2031,11 @@ public:
This event class contains information about command events, which originate
from a variety of simple controls.
Note that wxCommandEvents and wxCommandEvent-derived event classes by default
and unlike other wxEvent-derived classes propagate upward from the source
window (the window which emits the event) up to the first parent which processes
the event. Be sure to read @ref overview_events_propagation.
More complex controls, such as wxTreeCtrl, have separate command event classes.
@beginEventTable{wxCommandEvent}
@ -2534,6 +2540,12 @@ public:
This class adds some simple functionalities to wxCommandEvent coinceived
for inter-threads communications.
This event is not natively emitted by any control/class: this is just
an helper class for the user.
Its most important feature is the GetEventCategory() implementation which
allows thread events to @b NOT be processed by wxEventLoopBase::YieldFor calls
(unless the @c wxEVT_CATEGORY_THREAD is specified - which is never in wx code).
@library{wxcore}
@category{events}

9
interface/wx/progdlg.h
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@ -10,9 +10,16 @@
@class wxProgressDialog
This class represents a dialog that shows a short message and a
progress bar. Optionally, it can display ABORT and SKIP buttons,
progress bar. Optionally, it can display ABORT and SKIP buttons, and
the elapsed, remaining and estimated time for the end of the progress.
Note that you must be aware that wxProgressDialog internally calls
wxEventLoopBase::YieldFor with @c wxEVT_CATEGORY_UI and @c wxEVT_CATEGORY_USER_INPUT
and this may cause unwanted re-entrancies or the out-of-order processing
of pending events (to help preventing the last problem if you're using
wxProgressDialog in a multi-threaded application you should be sure to use
wxThreadEvent for your inter-threads communications).
@beginStyleTable
@style{wxPD_APP_MODAL}
Make the progress dialog modal. If this flag is not given, it is

31
interface/wx/thread.h
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@ -279,7 +279,7 @@ public:
Example:
@code
extern const wxEventType wxEVT_COMMAND_MYTHREAD_UPDATE;
wxDECLARE_EVENT(wxEVT_COMMAND_MYTHREAD_UPDATE, wxThreadEvent);
class MyFrame : public wxFrame, public wxThreadHelper
{
@ -298,7 +298,7 @@ public:
...
void DoStartALongTask();
void OnThreadUpdate(wxCommandEvent& evt);
void OnThreadUpdate(wxThreadEvent& evt);
void OnClose(wxCloseEvent& evt);
...
@ -312,7 +312,7 @@ public:
DECLARE_EVENT_TABLE()
};
DEFINE_EVENT_TYPE(wxEVT_COMMAND_MYTHREAD_UPDATE)
wxDEFINE_EVENT(wxEVT_COMMAND_MYTHREAD_UPDATE, wxThreadEvent)
BEGIN_EVENT_TABLE(MyFrame, wxFrame)
EVT_COMMAND(wxID_ANY, wxEVT_COMMAND_MYTHREAD_UPDATE, MyFrame::OnThreadUpdate)
EVT_CLOSE(MyFrame::OnClose)
@ -364,7 +364,7 @@ public:
// VERY IMPORTANT: do not call any GUI function inside this
// function; rather use wxQueueEvent():
wxQueueEvent(this, new wxCommandEvent(wxEVT_COMMAND_MYTHREAD_UPDATE));
wxQueueEvent(this, new wxThreadEvent(wxEVT_COMMAND_MYTHREAD_UPDATE));
// we used pointer 'this' assuming it's safe; see OnClose()
}
@ -386,7 +386,7 @@ public:
Destroy();
}
void MyFrame::OnThreadUpdate(wxCommandEvent&evt)
void MyFrame::OnThreadUpdate(wxThreadEvent& evt)
{
// ...do something... e.g. m_pGauge->Pulse();
@ -399,7 +399,7 @@ public:
@library{wxbase}
@category{threading}
@see wxThread
@see wxThread, wxThreadEvent
*/
class wxThreadHelper
{
@ -631,8 +631,8 @@ enum
@code
// declare a new type of event, to be used by our MyThread class:
extern const wxEventType wxEVT_COMMAND_MYTHREAD_COMPLETED;
extern const wxEventType wxEVT_COMMAND_MYTHREAD_UPDATE;
wxDECLARE_EVENT(wxEVT_COMMAND_MYTHREAD_COMPLETED, wxThreadEvent);
wxDECLARE_EVENT(wxEVT_COMMAND_MYTHREAD_UPDATE, wxThreadEvent);
class MyFrame;
class MyThread : public wxThread
@ -669,7 +669,8 @@ enum
// a resume routine would be nearly identic to DoPauseThread()
void DoResumeThread() { ... }
void OnThreadCompletion(wxCommandEvent&);
void OnThreadUpdate(wxThreadEvent&);
void OnThreadCompletion(wxThreadEvent&);
void OnClose(wxCloseEvent&);
protected:
@ -686,8 +687,8 @@ enum
EVT_COMMAND(wxID_ANY, wxEVT_COMMAND_MYTHREAD_COMPLETED, MyFrame::OnThreadCompletion)
END_EVENT_TABLE()
DEFINE_EVENT_TYPE(wxEVT_COMMAND_MYTHREAD_COMPLETED)
DEFINE_EVENT_TYPE(wxEVT_COMMAND_MYTHREAD_UPDATE)
wxDEFINE_EVENT(wxEVT_COMMAND_MYTHREAD_COMPLETED, wxThreadEvent)
wxDEFINE_EVENT(wxEVT_COMMAND_MYTHREAD_UPDATE, wxThreadEvent)
void MyFrame::DoStartThread()
{
@ -721,13 +722,13 @@ enum
{
// ... do a bit of work...
wxQueueEvent(m_pHandler, new wxCommandEvent(wxEVT_COMMAND_MYTHREAD_UPDATE));
wxQueueEvent(m_pHandler, new wxThreadEvent(wxEVT_COMMAND_MYTHREAD_UPDATE));
}
// signal the event handler that this thread is going to be destroyed
// NOTE: here we assume that using the m_pHandler pointer is safe,
// (in this case this is assured by the MyFrame destructor)
wxQueueEvent(m_pHandler, new wxCommandEvent(wxEVT_COMMAND_MYTHREAD_COMPLETED));
wxQueueEvent(m_pHandler, new wxThreadEvent(wxEVT_COMMAND_MYTHREAD_COMPLETED));
return (wxThread::ExitCode)0; // success
}
@ -740,12 +741,12 @@ enum
m_pHandler->m_pThread = NULL;
}
void MyFrame::OnThreadCompletion(wxCommandEvent&)
void MyFrame::OnThreadCompletion(wxThreadEvent&)
{
wxMessageOutputDebug().Printf("MYFRAME: MyThread exited!\n");
}
void MyFrame::OnThreadUpdate(wxCommandEvent&)
void MyFrame::OnThreadUpdate(wxThreadEvent&)
{
wxMessageOutputDebug().Printf("MYFRAME: MyThread update...\n");
}