qcoreevent.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

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**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
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** This file is part of the QtCore module of the Qt Toolkit.
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#include "qcoreevent.h"
#include "qcoreapplication.h"
#include "qcoreapplication_p.h"

/*!
    \class QEvent
    \brief The QEvent class is the base class of all
    event classes. Event objects contain event parameters.

    \ingroup events
    \ingroup environment

    Qt's main event loop (QCoreApplication::exec()) fetches native
    window system events from the event queue, translates them into
    QEvents, and sends the translated events to \l{QObject}s.

    In general, events come from the underlying window system
    (spontaneous() returns true), but it is also possible to manually
    send events using QCoreApplication::sendEvent() and
    QCoreApplication::postEvent() (spontaneous() returns false).

    QObjects receive events by having their QObject::event() function
    called. The function can be reimplemented in subclasses to
    customize event handling and add additional event types;
    QWidget::event() is a notable example. By default, events are
    dispatched to event handlers like QObject::timerEvent() and
    QWidget::mouseMoveEvent(). QObject::installEventFilter() allows an
    object to intercept events destined for another object.

    The basic QEvent contains only an event type parameter and an
    "accept" flag.  The accept flag set with accept(), and cleared
    with ignore(). It is set by default, but don't rely on this as
    subclasses may choose to clear it in their constructor.

    Subclasses of QEvent contain additional parameters that describe
    the particular event.

    \sa QObject::event(), QObject::installEventFilter(),
        QWidget::event(), QCoreApplication::sendEvent(),
        QCoreApplication::postEvent(), QCoreApplication::processEvents()
*/


/*!
    \enum QEvent::Type

    This enum type defines the valid event types in Qt. The event
    types and the specialized classes for each type are as follows:

    \value None                             Not an event.
    \value AccessibilityDescription         Used to query accessibility description texts (QAccessibleEvent).
    \value AccessibilityHelp                Used to query accessibility help texts (QAccessibleEvent).
    \value AccessibilityPrepare             Accessibility information is requested.
    \value ActionAdded                      A new action has been added (QActionEvent).
    \value ActionChanged                    An action has been changed (QActionEvent).
    \value ActionRemoved                    An action has been removed (QActionEvent).
    \value ActivationChange                 A widget's top-level window activation state has changed.
    \value ApplicationActivated             The application has been made available to the user.
    \value ApplicationDeactivated           The application has been suspended, and is unavailable to the user.
    \value ApplicationFontChange            The default application font has changed.
    \value ApplicationLayoutDirectionChange The default application layout direction has changed.
    \value ApplicationPaletteChange         The default application palette has changed.
    \value ApplicationWindowIconChange      The application's icon has changed.
    \value ChildAdded                       An object gets a child (QChildEvent).
    \value ChildPolished                    A widget child gets polished (QChildEvent).
    \value ChildRemoved                     An object loses a child (QChildEvent).
    \value Clipboard                        The clipboard contents have changed (QClipboardEvent).
    \value Close                            Widget was closed (QCloseEvent).
    \value ContextMenu                      Context popup menu (QContextMenuEvent).
    \value DeferredDelete                   The object will be deleted after it has cleaned up.
    \value DragEnter                        The cursor enters a widget during a drag and drop action (QDragEnterEvent).
    \value DragLeave                        The cursor leaves a widget during a drag and drop action (QDragLeaveEvent).
    \value DragMove                         A drag and drop action is in progress (QDragMoveEvent).
    \value Drop                             A drag and drop action is completed (QDropEvent).
    \value EnabledChange                    Widget's enabled state has changed.
    \value Enter                            Mouse enters widget's boundaries.
    \value EnterWhatsThisMode               Send to toplevel widgets when the application enters "What's This?" mode.
    \value FileOpen                         File open request (QFileOpenEvent).
    \value FocusIn                          Widget gains keyboard focus (QFocusEvent).
    \value FocusOut                         Widget loses keyboard focus (QFocusEvent).
    \value FontChange                       Widget's font has changed.
    \value Hide                             Widget was hidden (QHideEvent).
    \value HideToParent                     A child widget has been hidden.
    \value HoverEnter                       The mouse cursor enters a hover widget (QHoverEvent).
    \value HoverLeave                       The mouse cursor leaves a hover widget (QHoverEvent).
    \value HoverMove                        The mouse cursor moves inside a hover widget (QHoverEvent).
    \value IconDrag                         The main icon of a window has been dragged away (QIconDragEvent).
    \value IconTextChange                   Widget's icon text has been changed.
    \value InputMethod                      An input method is being used (QInputMethodEvent).
    \value KeyPress                         Key press (QKeyEvent).
    \value KeyRelease                       Key release (QKeyEvent).
    \value LanguageChange                   The application translation changed.
    \value LayoutDirectionChange            The direction of layouts changed.
    \value LayoutRequest                    Widget layout needs to be redone.
    \value Leave                            Mouse leaves widget's boundaries.
    \value LeaveWhatsThisMode               Send to toplevel widgets when the application leaves "What's This?" mode.
    \value LocaleChange                     The system locale has changed.
    \value MenubarUpdated                   The window's menu bar has been updated.
    \value MetaCall                         An asynchronous method invocation via QMetaObject::invokeMethod().
    \value ModifiedChange                   Widgets modification state has been changed.
    \value MouseButtonDblClick              Mouse press again (QMouseEvent).
    \value MouseButtonPress                 Mouse press (QMouseEvent).
    \value MouseButtonRelease               Mouse release (QMouseEvent).
    \value MouseMove                        Mouse move (QMouseEvent).
    \value MouseTrackingChange              The mouse tracking state has changed.
    \value Move                             Widget's position changed (QMoveEvent).
    \value Paint                            Screen update necessary (QPaintEvent).
    \value PaletteChange                    Palette of the widget changed.
    \value ParentAboutToChange              The widget parent is about to change.
    \value ParentChange                     The widget parent has changed.
    \value Polish                           The widget is polished.
    \value PolishRequest                    The widget should be polished.
    \value QueryWhatsThis                   The widget should accept the event if it has "What's This?" help.
    \value Resize                           Widget's size changed (QResizeEvent).
    \value Shortcut                         Key press in child for shortcut key handling (QShortcutEvent).
    \value ShortcutOverride                 Key press in child, for overriding shortcut key handling (QKeyEvent).
    \value Show                             Widget was shown on screen (QShowEvent).
    \value ShowToParent                     A child widget has been shown.
    \value SockAct                          Socket activated, used to implement QSocketNotifier.
    \value StatusTip                        A status tip is requested (QStatusTipEvent).
    \value StyleChange                      Widget's style has been changed.
    \value TabletMove                       Wacom tablet move (QTabletEvent).
    \value TabletPress                      Wacom tablet press (QTabletEvent).
    \value TabletRelease                    Wacom tablet release (QTabletEvent).
    \value Timer                            Regular timer events (QTimerEvent).
    \value ToolBarChange                    The toolbar button is toggled on Mac OS X.
    \value ToolTip                          A tooltip was requested (QHelpEvent).
    \value UpdateLater                      The widget should be queued to be repainted at a later time.
    \value UpdateRequest                    The widget should be repainted.
    \value WhatsThis                        The widget should reveal "What's This?" help (QHelpEvent).
    \value WhatsThisClicked                 A link in a widget's "What's This?" help was clicked.
    \value Wheel                            Mouse wheel rolled (QWheelEvent).
    \value WinEventAct                      A Windows-specific activation event has occurred.
    \value WindowActivate                   Window was activated.
    \value WindowBlocked                    The window is blocked by a modal dialog.
    \value WindowDeactivate                 Window was deactivated.
    \value WindowIconChange                 The window's icon has changed.
    \value WindowStateChange                The \l{QWidget::windowState()}{window's state} (minimized, maximized or full-screen) has changed (QWindowStateChangeEvent).
    \value WindowTitleChange                The window title has changed.
    \value WindowUnblocked                  The window is unblocked after a modal dialog exited.
    \value ZOrderChange                     The widget's z-order has changed. This event is never sent to top level windows.

    User events should have values between \c User and \c{MaxUser}:

    \value User                             User-defined event.
    \value MaxUser                          Last user event ID.

    \omitvalue Accel
    \omitvalue AccelAvailable
    \omitvalue AccelOverride
    \omitvalue AcceptDropsChange
    \omitvalue ActivateControl
    \omitvalue CaptionChange
    \omitvalue ChildInserted
    \omitvalue Create
    \omitvalue DeactivateControl
    \omitvalue Destroy
    \omitvalue DragResponse
    \omitvalue EmbeddingControl
    \omitvalue HelpRequest
    \omitvalue IconChange
    \omitvalue LayoutHint
    \omitvalue OkRequest
    \omitvalue Quit
    \omitvalue Reparent
    \omitvalue ShowWindowRequest
    \omitvalue Speech
    \omitvalue Style
    \omitvalue ThreadChange
    \omitvalue ZeroTimerEvent
*/

/*!
    Contructs an event object of type \a type.
*/
QEvent::QEvent(Type type)
    : d(0), t(type), posted(false), spont(false), m_accept(true)
{}

/*!
    Destroys the event. If it was \link
    QCoreApplication::postEvent() posted \endlink,
    it will be removed from the list of events to be posted.
*/

QEvent::~QEvent()
{
    if (posted && QCoreApplication::instance())
        QCoreApplicationPrivate::removePostedEvent(this);
}


/*!
    \property  QEvent::accepted
    the accept flag of the event object

    Setting the accept parameter indicates that the event receiver
    wants the event. Unwanted events might be propagated to the parent
    widget. By default, isAccepted() is set to true, but don't rely on
    this as subclasses may choose to clear it in their constructor.