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#include "qwidgetaction.h"

#include "qdebug.h"

#ifndef QT_NO_ACTION

#include "qwidgetaction_p.h"

QT_BEGIN_NAMESPACE

/*!

    \class QWidgetAction

    \since 4.2

    \brief The QWidgetAction class extends QAction by an interface

    for inserting custom widgets into action based containers, such

    as toolbars.

    \ingroup mainwindow-classes

    Most actions in an application are represented as items in menus or

    buttons in toolbars. However sometimes more complex widgets are

    necessary. For example a zoom action in a word processor may be

    realized using a QComboBox in a QToolBar, presenting a range

    of different zoom levels. QToolBar provides QToolBar::insertWidget()

    as convenience function for inserting a single widget.

    However if you want to implement an action that uses custom

    widgets for visualization in multiple containers then you have to

    subclass QWidgetAction.

    If a QWidgetAction is added for example to a QToolBar then

    QWidgetAction::createWidget() is called. Reimplementations of that

    function should create a new custom widget with the specified parent.

    If the action is removed from a container widget then

    QWidgetAction::deleteWidget() is called with the previously created custom

    widget as argument. The default implementation hides the widget and deletes

    it using QObject::deleteLater().

    If you have only one single custom widget then you can set it as default

    widget using setDefaultWidget(). That widget will then be used if the

    action is added to a QToolBar, or in general to an action container that

    supports QWidgetAction. If a QWidgetAction with only a default widget is

    added to two toolbars at the same time then the default widget is shown

    only in the first toolbar the action was added to. QWidgetAction takes

    over ownership of the default widget.

    Note that it is up to the widget to activate the action, for example by

    reimplementing mouse event handlers and calling QAction::trigger().

    \bold {Mac OS X}: If you add a widget to a menu in the application's menu

    bar on Mac OS X, the widget will be added and it will function but with some

    limitations:

    \list 1

        \o The widget is reparented away from the QMenu to the native menu

            view. If you show the menu in some other place (e.g. as a popup menu),

            the widget will not be there.

        \o Focus/Keyboard handling of the widget is not possible.

        \o Due to Apple's design, mouse tracking on the widget currently does

            not work.

        \o Connecting the triggered() signal to a slot that opens a modal

            dialog will cause a crash in Mac OS X 10.4 (known bug acknowledged

            by Apple), a workaround is to use a QueuedConnection instead of a

            DirectConnection.

    \endlist

    \sa QAction, QActionGroup, QWidget

*/

/*!

    Constructs an action with \a parent.

*/

QWidgetAction::QWidgetAction(QObject *parent)

    : QAction(*(new QWidgetActionPrivate), parent)

{

}

/*!

    Destroys the object and frees allocated resources.

*/

QWidgetAction::~QWidgetAction()

{

    Q_D(QWidgetAction);

    for (int i = 0; i < d->createdWidgets.count(); ++i)

        disconnect(d->createdWidgets.at(i), SIGNAL(destroyed(QObject*)),

                   this, SLOT(_q_widgetDestroyed(QObject*)));

    QList<QWidget *> widgetsToDelete = d->createdWidgets;

    d->createdWidgets.clear();

    qDeleteAll(widgetsToDelete);

    delete d->defaultWidget;

}

/*!

    Sets \a widget to be the default widget. The ownership is

    transferred to QWidgetAction. Unless createWidget() is

    reimplemented by a subclass to return a new widget the default

    widget is used when a container widget requests a widget through

    requestWidget().

*/

void QWidgetAction::setDefaultWidget(QWidget *widget)

{

    Q_D(QWidgetAction);

    if (widget == d->defaultWidget || d->defaultWidgetInUse)

        return;

    delete d->defaultWidget;

    d->defaultWidget = widget;

    if (!widget)

        return;

    setVisible(!(widget->isHidden() && widget->testAttribute(Qt::WA_WState_ExplicitShowHide)));

    d->defaultWidget->hide();

    d->defaultWidget->setParent(0);

    d->defaultWidgetInUse = false;

    if (!isEnabled())

        d->defaultWidget->setEnabled(false);

}

/*!

    Returns the default widget.

*/

QWidget *QWidgetAction::defaultWidget() const

{

    Q_D(const QWidgetAction);

    return d->defaultWidget;

}

/*!

    Returns a widget that represents the action, with the given \a

    parent.

    Container widgets that support actions can call this function to

    request a widget as visual representation of the action.

    \sa releaseWidget(), createWidget(), defaultWidget()

*/

QWidget *QWidgetAction::requestWidget(QWidget *parent)

{

    Q_D(QWidgetAction);

    QWidget *w = createWidget(parent);

    if (!w) {

        if (d->defaultWidgetInUse || !d->defaultWidget)

            return 0;

        d->defaultWidget->setParent(parent);

        d->defaultWidgetInUse = true;

        return d->defaultWidget;

    }

    connect(w, SIGNAL(destroyed(QObject*)),

            this, SLOT(_q_widgetDestroyed(QObject*)));

    d->createdWidgets.append(w);

    return w;

}

/*!

    Releases the specified \a widget.

    Container widgets that support actions call this function when a widget

    action is removed.

    \sa requestWidget(), deleteWidget(), defaultWidget()

*/

void QWidgetAction::releaseWidget(QWidget *widget)

{

    Q_D(QWidgetAction);

    if (widget == d->defaultWidget) {

        d->defaultWidget->hide();

        d->defaultWidget->setParent(0);

        d->defaultWidgetInUse = false;

        return;

    }

    if (!d->createdWidgets.contains(widget))

        return;

    disconnect(widget, SIGNAL(destroyed(QObject *)),

               this, SLOT(_q_widgetDestroyed(QObject *)));

    d->createdWidgets.removeAll(widget);

    deleteWidget(widget);

}

/*!

    \reimp

*/

bool QWidgetAction::event(QEvent *event)

{

    Q_D(QWidgetAction);

    if (event->type() == QEvent::ActionChanged) {

        if (d->defaultWidget)

            d->defaultWidget->setEnabled(isEnabled());

        for (int i = 0; i < d->createdWidgets.count(); ++i)

            d->createdWidgets.at(i)->setEnabled(isEnabled());

    }

    return QAction::event(event);

}

/*!

    \reimp

 */

bool QWidgetAction::eventFilter(QObject *obj, QEvent *event)

{

    return QAction::eventFilter(obj,event);

}

/*!

    This function is called whenever the action is added to a container widget

    that supports custom widgets. If you don't want a custom widget to be

    used as representation of the action in the specified \a parent widget then

    0 should be returned.

    \sa deleteWidget()

*/

QWidget *QWidgetAction::createWidget(QWidget *parent)

{

    Q_UNUSED(parent)

    return 0;

}

/*!

    This function is called whenever the action is removed from a

    container widget that displays the action using a custom \a

    widget previously created using createWidget(). The default

    implementation hides the \a widget and schedules it for deletion

    using QObject::deleteLater().

    \sa createWidget()

*/

void QWidgetAction::deleteWidget(QWidget *widget)

{

    widget->hide();

    widget->deleteLater();

}

/*!

    Returns the list of widgets that have been using createWidget() and

    are currently in use by widgets the action has been added to.

*/

QList<QWidget *> QWidgetAction::createdWidgets() const

{

    Q_D(const QWidgetAction);

    return d->createdWidgets;

}

QT_END_NAMESPACE

#include "moc_qwidgetaction.cpp"

#endif // QT_NO_ACTION