q3listbox.cpp

奇趣公司比较新的qt/emd版本

    pixmap \a pixmap. The item gets inserted after the item \a after,
    or at the beginning if \a after is 0.
*/

Q3ListBoxPixmap::Q3ListBoxPixmap(Q3ListBox* listbox, const QPixmap &pixmap, Q3ListBoxItem *after)
    : Q3ListBoxItem(listbox, after)
{
    pm = pixmap;
}


/*!
    Destroys the item.
*/

Q3ListBoxPixmap::~Q3ListBoxPixmap()
{
}


/*!
    Constructs a new list box item in list box \a listbox showing the
    pixmap \a pix and the text \a text.
*/
Q3ListBoxPixmap::Q3ListBoxPixmap(Q3ListBox* listbox, const QPixmap &pix, const QString& text)
    : Q3ListBoxItem(listbox)
{
    pm = pix;
    setText(text);
}

/*!
    Constructs a new list box item showing the pixmap \a pix and the
    text to \a text.
*/
Q3ListBoxPixmap::Q3ListBoxPixmap(const QPixmap & pix, const QString& text)
    : Q3ListBoxItem()
{
    pm = pix;
    setText(text);
}

/*!
    Constructs a new list box item in list box \a listbox showing the
    pixmap \a pix and the string \a text. The item gets inserted after
    the item \a after, or at the beginning if \a after is 0.
*/
Q3ListBoxPixmap::Q3ListBoxPixmap(Q3ListBox* listbox, const QPixmap & pix, const QString& text,
                                Q3ListBoxItem *after)
    : Q3ListBoxItem(listbox, after)
{
    pm = pix;
    setText(text);
}

/*!
    \fn const QPixmap *Q3ListBoxPixmap::pixmap() const

    Returns the pixmap associated with the item.
*/


/*!
    Draws the pixmap using \a painter.
*/

void Q3ListBoxPixmap::paint(QPainter *painter)
{
    int itemHeight = height(listBox());
    int yPos;

    const QPixmap *pm = pixmap();
    if (pm && ! pm->isNull()) {
        yPos = (itemHeight - pm->height()) / 2;
        painter->drawPixmap(3, yPos, *pm);
    }

    if (!text().isEmpty()) {
        QFontMetrics fm = painter->fontMetrics();
        yPos = ((itemHeight - fm.height()) / 2) + fm.ascent();
        painter->drawText(pm->width() + 5, yPos, text());
    }
}

/*!
    Returns the height of the pixmap in list box \a lb.

    \sa paint(), width()
*/

int Q3ListBoxPixmap::height(const Q3ListBox* lb) const
{
    int h;
    if (text().isEmpty())
        h = pm.height();
    else
        h = qMax(pm.height(), lb->fontMetrics().lineSpacing() + 2);
    return qMax(h, QApplication::globalStrut().height());
}

/*!
    Returns the width of the pixmap plus some margin in list box \a lb.

    \sa paint(), height()
*/

int Q3ListBoxPixmap::width(const Q3ListBox* lb) const
{
    if (text().isEmpty())
        return qMax(pm.width() + 6, QApplication::globalStrut().width());
    return qMax(pm.width() + lb->fontMetrics().width(text()) + 6,
            QApplication::globalStrut().width());
}

/*!
    \fn int Q3ListBoxPixmap::rtti() const

    \reimp

    Returns 2.

    Make your derived classes return their own values for rtti(), and
    you can distinguish between listbox items. You should use values
    greater than 1000 preferably a large random number, to allow for
    extensions to this class.
*/

int Q3ListBoxPixmap::rtti() const
{
    return RTTI;
}

/*!
    \class Q3ListBox qlistbox.h
    \brief The Q3ListBox widget provides a list of selectable, read-only items.

    \compat

    This is typically a single-column list in which either no item or
    one item is selected, but it can also be used in many other ways.

    Q3ListBox will add scroll bars as necessary, but it isn't intended
    for \e really big lists. If you want more than a few thousand
    items, it's probably better to use a different widget mainly
    because the scroll bars won't provide very good navigation, but
    also because Q3ListBox may become slow with huge lists. (See
    Q3ListView and Q3Table for possible alternatives.)

    There are a variety of selection modes described in the
    Q3ListBox::SelectionMode documentation. The default is \l Single
    selection mode, but you can change it using setSelectionMode().
    (setMultiSelection() is still provided for compatibility with Qt
    1.x. We recommend using setSelectionMode() in all code.)

    Because Q3ListBox offers multiple selection it must display
    keyboard focus and selection state separately. Therefore there are
    functions both to set the selection state of an item, i.e.
    setSelected(), and to set which item displays keyboard focus, i.e.
    setCurrentItem().

    The list box normally arranges its items in a single column and
    adds a vertical scroll bar if required. It is possible to have a
    different fixed number of columns (setColumnMode()), or as many
    columns as will fit in the list box's assigned screen space
    (setColumnMode(FitToWidth)), or to have a fixed number of rows
    (setRowMode()) or as many rows as will fit in the list box's
    assigned screen space (setRowMode(FitToHeight)). In all these
    cases Q3ListBox will add scroll bars, as appropriate, in at least
    one direction.

    If multiple rows are used, each row can be as high as necessary
    (the normal setting), or you can request that all items will have
    the same height by calling setVariableHeight(false). The same
    applies to a column's width, see setVariableWidth().

    The Q3ListBox's items are Q3ListBoxItem objects. Q3ListBox provides
    methods to insert new items as strings, as pixmaps, and as
    Q3ListBoxItem * (insertItem() with various arguments), and to
    replace an existing item with a new string, pixmap or Q3ListBoxItem
    (changeItem() with various arguments). You can also remove items
    singly with removeItem() or clear() the entire list box. Note that
    if you create a Q3ListBoxItem yourself and insert it, Q3ListBox
    takes ownership of the item.

    You can also create a Q3ListBoxItem, such as Q3ListBoxText or
    Q3ListBoxPixmap, with the list box as first parameter. The item
    will then append itself. When you delete an item it is
    automatically removed from the list box.

    The list of items can be arbitrarily large; Q3ListBox will add
    scroll bars if necessary. Q3ListBox can display a single-column
    (the common case) or multiple-columns, and offers both single and
    multiple selection. Q3ListBox does not support multiple-column
    items (but Q3ListView and Q3Table do), or tree hierarchies (but
    Q3ListView does).

    The list box items can be accessed both as Q3ListBoxItem objects
    (recommended) and using integer indexes (the original Q3ListBox
    implementation used an array of strings internally, and the API
    still supports this mode of operation). Everything can be done
    using the new objects, and most things can be done using indexes.

    Each item in a Q3ListBox contains a Q3ListBoxItem. One of the items
    can be the current item. The currentChanged() signal and the
    highlighted() signal are emitted when a new item becomes current,
    e.g. because the user clicks on it or Q3ListBox::setCurrentItem()
    is called. The selected() signal is emitted when the user
    double-clicks on an item or presses Enter on the current item.

    If the user does not select anything, no signals are emitted and
    currentItem() returns -1.

    A list box has Qt::WheelFocus as a default focusPolicy(), i.e. it
    can get keyboard focus by tabbing, clicking and through the use of
    the mouse wheel.

    New items can be inserted using insertItem(), insertStrList() or
    insertStringList().

    By default, vertical and horizontal scroll bars are added and
    removed as necessary. setHScrollBarMode() and setVScrollBarMode()
    can be used to change this policy.

    If you need to insert types other than strings and pixmaps, you
    must define new classes which inherit Q3ListBoxItem.

    \warning The list box assumes ownership of all list box items and
    will delete them when it does not need them any more.

    \inlineimage qlistbox-m.png Screenshot in Motif style
    \inlineimage qlistbox-w.png Screenshot in Windows style

    \sa Q3ListView, QComboBox, QButtonGroup
*/

/*!
    \enum Q3ListBox::SelectionMode

    This enumerated type is used by Q3ListBox to indicate how it reacts
    to selection by the user.

    \value Single  When the user selects an item, any already-selected
    item becomes unselected and the user cannot unselect the selected
    item. This means that the user can never clear the selection, even
    though the selection may be cleared by the application programmer
    using Q3ListBox::clearSelection().

    \value Multi  When the user selects an item the selection status
    of that item is toggled and the other items are left alone.

    \value Extended When the user selects an item the selection is
    cleared and the new item selected. However, if the user presses
    the Ctrl key when clicking on an item, the clicked item gets
    toggled and all other items are left untouched. And if the user
    presses the Shift key while clicking on an item, all items between
    the current item and the clicked item get selected or unselected,
    depending on the state of the clicked item. Also, multiple items
    can be selected by dragging the mouse while the left mouse button
    is kept pressed.

    \value NoSelection  Items cannot be selected.

    In other words, \c Single is a real single-selection list box, \c
    Multi is a real multi-selection list box, \c Extended is a list
    box in which users can select multiple items but usually want to
    select either just one or a range of contiguous items, and \c
    NoSelection is for a list box where the user can look but not
    touch.
*/


/*!
    \enum Q3ListBox::LayoutMode

    This enum type is used to specify how Q3ListBox lays out its rows
    and columns.

    \value FixedNumber  There is a fixed number of rows (or columns).

    \value FitToWidth   There are as many columns as will fit
    on-screen.

    \value FitToHeight  There are as many rows as will fit on-screen.

    \value Variable  There are as many rows as are required by the
    column mode. (Or as many columns as required by the row mode.)

    Example: When you call setRowMode(FitToHeight), columnMode()
    automatically becomes \c Variable to accommodate the row mode
    you've set.
*/

/*!
    \fn void  Q3ListBox::onItem(Q3ListBoxItem *i)

    This signal is emitted when the user moves the mouse cursor onto
    an item, similar to the QWidget::enterEvent() function. \a i is
    the Q3ListBoxItem that the mouse has moved on.
*/

// ### bug here too? enter/leave event may noit considered. move the
// mouse out of the window and back in, to the same item - does it
// work?

/*!
    \fn void  Q3ListBox::onViewport()

    This signal is emitted when the user moves the mouse cursor from
    an item to an empty part of the list box.
*/


/*!
    Constructs a new empty list box called \a name and with parent \a
    parent and widget attributes \a f.

    This constructor sets the Qt::WA_StaticContent and the
    Qt::WA_NoBackground attributes to boost performance when drawing
    Q3ListBoxItems. This may be unsuitable for custom Q3ListBoxItem
    classes, in which case Qt::WA_StaticContents and Qt::WA_NoBackground
    should be cleared on the viewport() after construction.
*/

Q3ListBox::Q3ListBox(QWidget *parent, const char *name, Qt::WindowFlags f)
    : Q3ScrollView(parent, name, f | Qt::WStaticContents | Qt::WNoAutoErase)
{
    d = new Q3ListBoxPrivate(this);
    d->updateTimer = new QTimer(this, "listbox update timer");
    d->visibleTimer = new QTimer(this, "listbox visible timer");
    d->inputTimer = new QTimer(this, "listbox input timer");
    d->resizeTimer = new QTimer(this, "listbox resize timer");
    d->clearing = false;
    d->pressedItem = 0;
    d->selectAnchor = 0;
    d->select = false;
    d->rubber = 0;

    setMouseTracking(true);
    viewport()->setMouseTracking(true);

    connect(d->updateTimer, SIGNAL(timeout()),
             this, SLOT(refreshSlot()));
    connect(d->visibleTimer, SIGNAL(timeout()),
             this, SLOT(ensureCurrentVisible()));
    connect(d->resizeTimer, SIGNAL(timeout()),
             this, SLOT(adjustItems()));
    viewport()->setBackgroundRole(QPalette::Base);
    viewport()->setFocusProxy(this);
    viewport()->setFocusPolicy(Qt::WheelFocus);
    setFocusPolicy(Qt::WheelFocus);
    setAttribute(Qt::WA_MacShowFocusRect);
}


Q3ListBox * Q3ListBox::changedListBox = 0;

/*!
    Destroys the list box. Deletes all list box items.
*/

Q3ListBox::~Q3ListBox()
{
    if (changedListBox == this)
        changedListBox = 0;
    clear();
    delete d;
    d = 0;
}

/*!
    \fn void Q3ListBox::pressed(Q3ListBoxItem *item)

    This signal is emitted when the user presses any mouse button. If
    \a item is not 0, the cursor is on \a item. If \a item is 0, the
    mouse cursor isn't on any item.

    Note that you must not delete any Q3ListBoxItem objects in slots
    connected to this signal.
*/

/*!
    \fn void Q3ListBox::pressed(Q3ListBoxItem *item, const QPoint &pnt)
    \overload

    This signal is emitted when the user presses any mouse button. If
    \a item is not 0, the cursor is on \a item. If \a item is 0, the
    mouse cursor isn't on any item.

    \a pnt is the position of the mouse cursor in the global
    coordinate system (QMouseEvent::globalPos()).

    Note that you must not delete any Q3ListBoxItem objects in slots
    connected to this signal.

    \sa mouseButtonPressed() rightButtonPressed() clicked()
*/

/*!
    \fn void Q3ListBox::clicked(Q3ListBoxItem *item)

    This signal is emitted when the user clicks any mouse button. If
    \a item is not 0, the cursor is on \a item. If \a item is 0, the
    mouse cursor isn't on any item.

    Note that you must not delete any Q3ListBoxItem objects in slots
    connected to this signal.
*/

/*!
    \fn void Q3ListBox::clicked(Q3ListBoxItem *item, const QPoint &pnt)
    \overload

    This signal is emitted when the user clicks any mouse button. If
    \a item is not 0, the cursor is on \a item. If \a item is 0, the
    mouse cursor isn't on any item.

    \a pnt is the position of the mouse cursor in the global
    coordinate system (QMouseEvent::globalPos()). (If the click's
    press and release differs by a pixel or two, \a pnt is the
    position at release time.)

    Note that you must not delete any Q3ListBoxItem objects in slots
    connected to this signal.
*/

/*!
    \fn void Q3ListBox::mouseButtonClicked (int button, Q3ListBoxItem * item, const QPoint & pos)

    This signal is emitted when the user clicks mouse button \a
    button. If \a item is not 0, the cursor is on \a item. If \a item
    is 0, the mouse cursor isn't on any item.

    \a pos is the position of the mouse cursor in the global
    coordinate system (QMouseEvent::globalPos()). (If the click's
    press and release differs by a pixel or two, \a pos is the
    position at release time.)

    Note that you must not delete any Q3ListBoxItem objects in slots
    connected to this signal.
*/

/*!
    \fn void Q3ListBox::mouseButtonPressed (int button, Q3ListBoxItem * item, const QPoint & pos)

    This signal is emitted when the user presses mouse button \a
    button. If \a item is not 0, the cursor is on \a item. If \a item
    is 0, the mouse cursor isn't on any item.

    \a pos is the position of the mouse cursor in the global
    coordinate system (QMouseEvent::globalPos()).

    Note that you must not delete any Q3ListBoxItem objects in slots
    connected to this signal.
*/

/*!
    \fn void Q3ListBox::doubleClicked(Q3ListBoxItem *item)

    This signal is emitted whenever an item is double-clicked. It's
    emitted on the second button press, not the second button release.
    If \a item is not 0, the cursor is on \a item. If \a item is 0,
    the mouse cursor isn't on any item.
*/


/*!
    \fn void Q3ListBox::returnPressed(Q3ListBoxItem *item)

    This signal is emitted when Enter or Return is pressed. The