qcombobox.cpp

奇趣公司比较新的qt/emd版本

void QComboBoxPrivateContainer::updateScrollers()
{
#ifndef QT_NO_SCROLLBAR
    if (!top || !bottom)
        return;

    if (isVisible() == false)
        return;

    QStyleOptionComboBox opt = comboStyleOption();
    if (combo->style()->styleHint(QStyle::SH_ComboBox_Popup, &opt, combo) &&
        view->verticalScrollBar()->minimum() < view->verticalScrollBar()->maximum()) {

        bool needTop = view->verticalScrollBar()->value()
                       > (view->verticalScrollBar()->minimum() + spacing());
        bool needBottom = view->verticalScrollBar()->value()
                          < (view->verticalScrollBar()->maximum() - spacing()*2);
        if (needTop)
            top->show();
        else
            top->hide();
        if (needBottom)
            bottom->show();
        else
            bottom->hide();
    } else {
        top->hide();
        bottom->hide();
    }
#endif // QT_NO_SCROLLBAR
}

/*
    Cleans up when the view is destroyed.
*/
void QComboBoxPrivateContainer::viewDestroyed()
{
    view = 0;
    setItemView(new QComboBoxListView());
}

/*
    Sets currentIndex on entered if the LeftButton is not pressed. This
    means that if mouseTracking(...) is on, we setCurrentIndex and select
    even when LeftButton is not pressed.
*/
void QComboBoxPrivateContainer::setCurrentIndex(const QModelIndex &index)
{
    view->selectionModel()->setCurrentIndex(index, QItemSelectionModel::ClearAndSelect);
}

/*
    Returns the item view used for the combobox popup.
*/
QAbstractItemView *QComboBoxPrivateContainer::itemView() const
{
    return view;
}

/*!
    Sets the item view to be used for the combobox popup.
*/
void QComboBoxPrivateContainer::setItemView(QAbstractItemView *itemView)
{
    Q_ASSERT(itemView);

    // clean up old one
    if (view) {
        view->removeEventFilter(this);
        view->viewport()->removeEventFilter(this);
#ifndef QT_NO_SCROLLBAR
        disconnect(view->verticalScrollBar(), SIGNAL(valueChanged(int)),
                   this, SLOT(updateScrollers()));
        disconnect(view->verticalScrollBar(), SIGNAL(rangeChanged(int,int)),
                   this, SLOT(updateScrollers()));
#endif
        disconnect(view, SIGNAL(entered(QModelIndex)),
                   this, SLOT(setCurrentIndex(QModelIndex)));
        disconnect(view, SIGNAL(destroyed()),
                   this, SLOT(viewDestroyed()));
        delete view;
        view = 0;
    }

    // setup the item view
    view = itemView;
    view->setParent(this);
    view->setAttribute(Qt::WA_MacShowFocusRect, false);
    qobject_cast<QBoxLayout*>(layout())->insertWidget(top ? 1 : 0, view);
    view->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    view->installEventFilter(this);
    view->viewport()->installEventFilter(this);
    view->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    QStyleOptionComboBox opt = comboStyleOption();
    const bool usePopup = combo->style()->styleHint(QStyle::SH_ComboBox_Popup, &opt, combo);
#ifndef QT_NO_SCROLLBAR
    if (usePopup)
        view->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
#endif
    if (combo->style()->styleHint(QStyle::SH_ComboBox_ListMouseTracking, &opt, combo) ||
        usePopup) {
        view->setMouseTracking(true);
    }
    view->setSelectionMode(QAbstractItemView::SingleSelection);
    view->setFrameStyle(QFrame::NoFrame);
    view->setLineWidth(0);
    view->setEditTriggers(QAbstractItemView::NoEditTriggers);
#ifndef QT_NO_SCROLLBAR
    connect(view->verticalScrollBar(), SIGNAL(valueChanged(int)),
            this, SLOT(updateScrollers()));
    connect(view->verticalScrollBar(), SIGNAL(rangeChanged(int,int)),
            this, SLOT(updateScrollers()));
#endif
    connect(view, SIGNAL(entered(QModelIndex)),
            this, SLOT(setCurrentIndex(QModelIndex)));
    connect(view, SIGNAL(destroyed()),
            this, SLOT(viewDestroyed()));
}

/*!
    Returns the spacing between the items in the view.
*/
int QComboBoxPrivateContainer::spacing() const
{
    QListView *lview = qobject_cast<QListView*>(view);
    if (lview)
        return lview->spacing();
    return 0;
}

void QComboBoxPrivateContainer::updateTopBottomMargin()
{
    if (!layout() || layout()->count() < 1)
        return;

    QBoxLayout *boxLayout = qobject_cast<QBoxLayout *>(layout());
    if (!boxLayout)
        return;

    const QStyleOptionComboBox opt = comboStyleOption();
    const bool usePopup = combo->style()->styleHint(QStyle::SH_ComboBox_Popup, &opt, combo);
    const int margin = usePopup ? combo->style()->pixelMetric(QStyle::PM_MenuVMargin, &opt, combo) : 0;

    QSpacerItem *topSpacer = boxLayout->itemAt(0)->spacerItem();
    if (topSpacer)
        topSpacer->changeSize(0, margin, QSizePolicy::Minimum, QSizePolicy::Fixed);

    QSpacerItem *bottomSpacer = boxLayout->itemAt(boxLayout->count() - 1)->spacerItem();
    if (bottomSpacer && bottomSpacer != topSpacer)
        bottomSpacer->changeSize(0, margin, QSizePolicy::Minimum, QSizePolicy::Fixed);

    boxLayout->invalidate();
}

void QComboBoxPrivateContainer::changeEvent(QEvent *e)
{
    if (e->type() == QEvent::StyleChange) {
        QStyleOptionComboBox opt = comboStyleOption();
        view->setMouseTracking(combo->style()->styleHint(QStyle::SH_ComboBox_ListMouseTracking, &opt, combo) ||
                               combo->style()->styleHint(QStyle::SH_ComboBox_Popup, &opt, combo));
        setFrameStyle(combo->style()->styleHint(QStyle::SH_ComboBox_PopupFrameStyle, &opt, combo));
    }
    QWidget::changeEvent(e);
}


bool QComboBoxPrivateContainer::eventFilter(QObject *o, QEvent *e)
{
    switch (e->type()) {
    case QEvent::KeyPress:
        switch (static_cast<QKeyEvent*>(e)->key()) {
        case Qt::Key_Enter:
        case Qt::Key_Return:
#ifdef QT_KEYPAD_NAVIGATION
        case Qt::Key_Select:
#endif
            if (view->currentIndex().isValid() && (view->currentIndex().flags() & Qt::ItemIsEnabled) ) {
                combo->hidePopup();
                emit itemSelected(view->currentIndex());
            }
            return true;
        case Qt::Key_Down:
            if (!(static_cast<QKeyEvent*>(e)->modifiers() & Qt::AltModifier))
                break;
            // fall through
        case Qt::Key_F4:
        case Qt::Key_Escape:
#ifdef QT_KEYPAD_NAVIGATION
        case Qt::Key_Back:
#endif
            combo->hidePopup();
            return true;
        default:
            break;
        }
    break;
    case QEvent::MouseMove: {
        if (isVisible()) {
            QMouseEvent *m = static_cast<QMouseEvent *>(e);
            QPoint vector = m->pos() - initialClickPosition;
            if (vector.manhattanLength() > 9 && blockMouseReleaseTimer.isActive())
                blockMouseReleaseTimer.stop();
        }
        break;
    }
    case QEvent::MouseButtonRelease: {
        QMouseEvent *m = static_cast<QMouseEvent *>(e);
        if (isVisible() && view->rect().contains(m->pos()) && view->currentIndex().isValid()
            && !blockMouseReleaseTimer.isActive()
            && (view->currentIndex().flags() & Qt::ItemIsEnabled)) {
            combo->hidePopup();
            emit itemSelected(view->currentIndex());
            return true;
        }
        break;
    }
    default:
        break;
    }
    return QFrame::eventFilter(o, e);
}

void QComboBoxPrivateContainer::showEvent(QShowEvent *)
{
    combo->update();
}

void QComboBoxPrivateContainer::hideEvent(QHideEvent *)
{
    emit resetButton();
    combo->update();
}

void QComboBoxPrivateContainer::mousePressEvent(QMouseEvent *e)
{

    QStyleOptionComboBox opt = comboStyleOption();
    opt.subControls = QStyle::SC_All;
    opt.activeSubControls = QStyle::SC_ComboBoxArrow;
    QStyle::SubControl sc = combo->style()->hitTestComplexControl(QStyle::CC_ComboBox, &opt,
                                                           combo->mapFromGlobal(e->globalPos()),
                                                           combo);
    if ((combo->isEditable() && sc == QStyle::SC_ComboBoxArrow)
        || (!combo->isEditable() && sc != QStyle::SC_None))
        setAttribute(Qt::WA_NoMouseReplay);
    QFrame::mousePressEvent(e);
}

void QComboBoxPrivateContainer::mouseReleaseEvent(QMouseEvent *e)
{
    Q_UNUSED(e);
    if (!blockMouseReleaseTimer.isActive()){
        combo->hidePopup();
        emit resetButton();
    }
}

QStyleOptionComboBox QComboBoxPrivateContainer::comboStyleOption() const
{
    QStyleOptionComboBox opt;
    opt.state = QStyle::State_None;
    opt.rect = combo->rect();
    opt.palette = combo->palette();
    opt.init(combo);
    opt.subControls = QStyle::SC_All;
    opt.activeSubControls = QStyle::SC_None;
    opt.editable = combo->isEditable();
    return opt;
}

/*!
    \enum QComboBox::InsertPolicy

    This enum specifies what the QComboBox should do when a new string is
    entered by the user.

    \value NoInsert             The string will not be inserted into the combobox.
    \value InsertAtTop          The string will be inserted as the first item in the combobox.
    \value InsertAtCurrent      The current item will be \e replaced by the string.
    \value InsertAtBottom       The string will be inserted after the last item in the combobox.
    \value InsertAfterCurrent   The string is inserted after the current item in the combobox.
    \value InsertBeforeCurrent  The string is inserted before the current item in the combobox.
    \value InsertAlphabetically The string is inserted in the alphabetic order in the combobox.
    \omitvalue NoInsertion
    \omitvalue AtTop
    \omitvalue AtCurrent
    \omitvalue AtBottom
    \omitvalue AfterCurrent
    \omitvalue BeforeCurrent
*/

/*!
    \enum QComboBox::SizeAdjustPolicy

    This enum specifies how the size hint of the QComboBox should
    adjust when new content is added or content changes.

    \value AdjustToContents              The combobox will always adjust to the contents
    \value AdjustToContentsOnFirstShow   The combobox will adjust to its contents the first time it is show.
    \value AdjustToMinimumContentsLength Use AdjustToContents or AdjustToContentsOnFirstShow instead.
    \value AdjustToMinimumContentsLengthWithIcon The combobox will adjust to \l minimumContentsLength plus space for an icon. For performance reasons use this policy on large models.
*/

/*!
    \fn void QComboBox::activated(int index)

    This signal is sent when an item in the combobox is activated by
    the user. The item's \a index is given.

*/

/*!
    \fn void QComboBox::activated(const QString &text)

    This signal is sent when an item in the combobox is activated by
    the user. The item's \a text is given.

*/

/*!
    \fn void QComboBox::highlighted(int index)

    This signal is sent when an item in the combobox popup list is highlighted by
    the user. The item's \a index is given.
*/

/*!
    \fn void QComboBox::highlighted(const QString &text)

    This signal is sent when an item in the combobox popup list is highlighted by
    the user. The item's \a text is given.
*/

/*!
    \fn void QComboBox::currentIndexChanged(int index)
    \since 4.1

    This signal is sent whenever the currentIndex in the combobox
    changes either through user interaction or programmatically. The
    item's \a index is given or -1 if the combobox becomes empty or the
    currentIndex was reset.
*/

/*!
    \fn void QComboBox::currentIndexChanged(const QString &text)
    \since 4.1

    This signal is sent whenever the currentIndex in the combobox
    changes either through user interaction or programmatically.  The
    item's \a text is given.
*/

/*!
    Constructs a combobox with the given \a parent, using the default
    model QStandardItemModel.
*/
QComboBox::QComboBox(QWidget *parent)
    : QWidget(*new QComboBoxPrivate(), parent, 0)
{
    Q_D(QComboBox);
    d->init();
}

/*!
  \internal
*/
QComboBox::QComboBox(QComboBoxPrivate &dd, QWidget *parent)
    : QWidget(dd, parent, 0)
{
    Q_D(QComboBox);
    d->init();
}

#ifdef QT3_SUPPORT
/*!
    Use one of the constructors that doesn't take the \a name
    argument and then use setObjectName() instead.
*/
QComboBox::QComboBox(QWidget *parent, const char *name)
    : QWidget(*new QComboBoxPrivate(), parent, 0)
{
    Q_D(QComboBox);
    d->init();
    setObjectName(QString::fromAscii(name));
}

/*!
    Use one of the constructors that doesn't take the \a name
    argument and then use setObjectName() instead.
*/
QComboBox::QComboBox(bool rw, QWidget *parent, const char *name)
    : QWidget(*new QComboBoxPrivate(), parent, 0)
{
    Q_D(QComboBox);
    d->init();
    setEditable(rw);
    setObjectName(QString::fromAscii(name));
}

#endif //QT3_SUPPORT

/*!
    \class QComboBox qcombobox.h
    \brief The QComboBox widget is a combined button and popup list.

    \ingroup basicwidgets
    \mainclass

    A QComboBox provides a means of presenting a list of options to the user
    in a way that takes up the minimum amount of screen space.

    A combobox is a selection widget that displays the current item,
    and can pop up a list of selectable items. A combobox may be editable,
    allowing the user to modify each item in the list.

    Comboboxes can contain pixmaps as well as strings; the
    insertItem() and setItemText() functions are suitably overloaded.
    For editable comboboxes, the function clearEditText() is provided,
    to clear the displayed string without changing the combobox's
    contents.

    There are two signals emitted if the current item of a combobox
    changes, currentIndexChanged() and activated().