qlistview.cpp

奇趣公司比较新的qt/emd版本

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#include "qlistview.h"

#ifndef QT_NO_LISTVIEW
#include <qabstractitemdelegate.h>
#include <qapplication.h>
#include <qpainter.h>
#include <qbitmap.h>
#include <qvector.h>
#include <qstyle.h>
#include <qevent.h>
#include <qscrollbar.h>
#include <qrubberband.h>
#include <private/qlistview_p.h>
#include <qdebug.h>
#ifndef QT_NO_ACCESSIBILITY
#include <qaccessible.h>
#endif

/*!
    \class QListView

    \brief The QListView class provides a list or icon view onto a model.

    \ingroup model-view
    \mainclass

    A QListView presents items stored in a model, either as a simple
    non-hierarchical list, or as a collection of icons. This class is used
    to provide lists and icon views that were previously provided by the
    \c QListBox and \c QIconView classes, but using the more flexible
    approach provided by Qt's model/view architecture.

    The QListView class is one of the \l{Model/View Classes}
    and is part of Qt's \l{Model/View Programming}{model/view framework}.

    This view does not display horizontal or vertical headers; to display
    a list of items with a horizontal header, use QTreeView instead.

    QListView implements the interfaces defined by the
    QAbstractItemView class to allow it to display data provided by
    models derived from the QAbstractItemModel class.

    Items in a list view can be displayed using one of two view modes:
    In \l ListMode, the items are displayed in the form of a simple list;
    in \l IconMode, the list view takes the form of an \e{icon view} in
    which the items are displayed with icons like files in a file manager.
    By default, the list view is in \l ListMode. To change the view mode,
    use the setViewMode() function, and to determine the current view mode,
    use viewMode().

    Items in these views are laid out in the direction specified by the
    flow() of the list view. The items may be fixed in place, or allowed
    to move, depending on the view's movement() state.

    If the items in the model cannot be completely laid out in the
    direction of flow, they can be wrapped at the boundary of the view
    widget; this depends on isWrapping(). This property is useful when the
    items are being represented by an icon view.

    The resizeMode() and layoutMode() govern how and when the items are
    laid out. Items are spaced according to their spacing(), and can exist
    within a notional grid of size specified by gridSize(). The items can
    be rendered as large or small icons depending on their iconSize().

    \table 100%
    \row \o \inlineimage windowsxp-listview.png Screenshot of a Windows XP style list view
         \o \inlineimage macintosh-listview.png Screenshot of a Macintosh style table view
         \o \inlineimage plastique-listview.png Screenshot of a Plastique style table view
    \row \o A \l{Windows XP Style Widget Gallery}{Windows XP style} list view.
         \o A \l{Macintosh Style Widget Gallery}{Macintosh style} list view.
         \o A \l{Plastique Style Widget Gallery}{Plastique style} list view.
    \endtable

    \section1 Improving Performance

    It is possible to give the view hints about the data it is handling in order
    to improve its performance when displaying large numbers of items. One approach
    that can be taken for views that are intended to display items with equal sizes
    is to set the \l uniformItemSizes property to true.

    \sa {View Classes}, QTreeView, QTableView, QListWidget
*/

/*!
    \enum QListView::ViewMode

    \value ListMode The items are laid out using TopToBottom flow, with Small size and Static movement
    \value IconMode The items are laid out using LeftToRight flow, with Large size and Free movement
*/

/*!
  \enum QListView::Movement

  \value Static The items cannot be moved by the user.
  \value Free The items can be moved freely by the user.
  \value Snap The items snap to the specified grid when moved; see
  setGridSize().
*/

/*!
  \enum QListView::Flow

  \value LeftToRight The items are laid out in the view from the left
  to the right.
  \value TopToBottom The items are laid out in the view from the top
  to the bottom.
*/

/*!
  \enum QListView::ResizeMode

  \value Fixed The items will only be laid out the first time the view is shown.
  \value Adjust The items will be laid out every time the view is resized.
*/

/*!
  \enum QListView::LayoutMode

  \value SinglePass The items are laid out all at once.
  \value Batched The items are laid out in batches of \l batchSize items.
  \sa batchSize
*/

/*!
  \since 4.2
  \fn void QListView::indexesMoved(const QModelIndexList &indexes)

  This signal is emitted when the specified \a indexes are moved in the view.
*/

/*!
    Creates a new QListView with the given \a parent to view a model.
    Use setModel() to set the model.
*/
QListView::QListView(QWidget *parent)
    : QAbstractItemView(*new QListViewPrivate, parent)
{
    setViewMode(ListMode);
    setSelectionMode(SingleSelection);
    setAttribute(Qt::WA_MacShowFocusRect);
}

/*!
  \internal
*/
QListView::QListView(QListViewPrivate &dd, QWidget *parent)
    : QAbstractItemView(dd, parent)
{
    setViewMode(ListMode);
    setSelectionMode(SingleSelection);
    setAttribute(Qt::WA_MacShowFocusRect);
}

/*!
  Destroys the view.
*/
QListView::~QListView()
{
}

/*!
    \property QListView::movement
    \brief whether the items can be moved freely, are snapped to a
    grid, or cannot be moved at all.

    This property determines how the user can move the items in the
    view. \l Static means that the items can't be moved the user. \l
    Free means that the user can drag and drop the items to any
    position in the view. \l Snap means that the user can drag and
    drop the items, but only to the positions in a notional grid
    signified by the gridSize property.

    Setting this property when the view is visible will cause the
    items to be laid out again.

    \sa gridSize, viewMode
*/
void QListView::setMovement(Movement movement)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Movement);
    d->movement = movement;

#ifndef QT_NO_DRAGANDDROP
    bool movable = (movement != Static);
    setDragEnabled(movable);
    d->viewport->setAcceptDrops(movable);
#endif
    d->doDelayedItemsLayout();
}

QListView::Movement QListView::movement() const
{
    Q_D(const QListView);
    return d->movement;
}

/*!
    \property QListView::flow
    \brief which direction the items layout should flow.

    If this property is \l LeftToRight, the items will be laid out left
    to right. If the \l isWrapping property is true, the layout will wrap
    when it reaches the right side of the visible area. If this
    property is \l TopToBottom, the items will be laid out from the top
    of the visible area, wrapping when it reaches the bottom.

    Setting this property when the view is visible will cause the
    items to be laid out again.

    \sa viewMode
*/
void QListView::setFlow(Flow flow)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Flow);
    d->flow = flow;
    d->doDelayedItemsLayout();
}

QListView::Flow QListView::flow() const
{
    Q_D(const QListView);
    return d->flow;
}

/*!
    \property QListView::isWrapping
    \brief whether the items layout should wrap.

    This property holds whether the layout should wrap when there is
    no more space in the visible area. The point at which the layout wraps
    depends on the \l flow property.

    Setting this property when the view is visible will cause the
    items to be laid out again.

    \sa viewMode
*/
void QListView::setWrapping(bool enable)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Wrap);
    d->setWrapping(enable);
    d->doDelayedItemsLayout();
}

bool QListView::isWrapping() const
{
    Q_D(const QListView);
    return d->isWrapping();
}

/*!
    \property QListView::resizeMode
    \brief whether the items are laid out again when the view is resized.

    If this property is \l Adjust, the items will be laid out again
    when the view is resized. If the value is \l Fixed, the items will
    not be laid out when the view is resized.

    \sa viewMode
*/
void QListView::setResizeMode(ResizeMode mode)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::ResizeMode);
    d->resizeMode = mode;
}

QListView::ResizeMode QListView::resizeMode() const
{
    Q_D(const QListView);
    return d->resizeMode;
}

/*!
    \property QListView::layoutMode
    \brief whether the layout of items should happen immediately or be delayed.

    This property holds the layout mode for the items. When the mode
    is \l SinglePass (the default), the items are laid out all in one go.
    When the mode is \l Batched, the items are laid out in batches of \l batchSize
    items, while processing events. This makes it possible to
    instantly view and interact with the visible items while the rest
    are being laid out.

    \sa viewMode
*/
void QListView::setLayoutMode(LayoutMode mode)
{
    Q_D(QListView);
    d->layoutMode = mode;
}

QListView::LayoutMode QListView::layoutMode() const
{
    Q_D(const QListView);
    return d->layoutMode;
}

/*!
    \property QListView::spacing
    \brief the space between items in the layout

    This property is the size of the empty space that is padded around
    an item in the layout.

    Setting this property when the view is visible will cause the
    items to be laid out again.

    \sa viewMode
*/
// ### Qt5: Use same semantic as layouts (spacing is the size of space 
// *between* items)
void QListView::setSpacing(int space)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Spacing);
    d->setSpacing(space);
    d->doDelayedItemsLayout();
}

int QListView::spacing() const
{
    Q_D(const QListView);
    return d->spacing();
}

/*!
    \property QListView::batchSize
    \brief the number of items laid out in each batch if \l layoutMode is
    set to \l Batched

    The default value is 100.

    \since 4.2
*/

void QListView::setBatchSize(int batchSize)
{