qitemdelegate.cpp

奇趣公司比较新的qt/emd版本

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#include "qitemdelegate.h"

#ifndef QT_NO_ITEMVIEWS
#include <qabstractitemmodel.h>
#include <qapplication.h>
#include <qbrush.h>
#include <qlineedit.h>
#include <qpainter.h>
#include <qpalette.h>
#include <qpoint.h>
#include <qrect.h>
#include <qsize.h>
#include <qstyle.h>
#include <qdatetime.h>
#include <qstyleoption.h>
#include <qevent.h>
#include <qpixmap.h>
#include <qbitmap.h>
#include <qpixmapcache.h>
#include <qitemeditorfactory.h>
#include <qmetaobject.h>
#include <qtextlayout.h>
#include <private/qobject_p.h>
#include <private/qdnd_p.h>
#include <private/qtextengine_p.h>
#include <qdebug.h>
#include <qlocale.h>

#include <limits.h>

class QItemDelegatePrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QItemDelegate)

public:
    QItemDelegatePrivate() : f(0), clipPainting(true) {}

    inline const QItemEditorFactory *editorFactory() const
        { return f ? f : QItemEditorFactory::defaultFactory(); }

    inline QIcon::Mode iconMode(QStyle::State state) const
        {
            if (!(state & QStyle::State_Enabled)) return QIcon::Disabled;
            if (state & QStyle::State_Selected) return QIcon::Selected;
            return QIcon::Normal;
        }

    inline QIcon::State iconState(QStyle::State state) const
        { return state & QStyle::State_Open ? QIcon::On : QIcon::Off; }

    inline static QString replaceNewLine(QString text)
        {
            const QChar nl = QLatin1Char('\n');
            for (int i = 0; i < text.count(); ++i)
                if (text.at(i) == nl)
                    text[i] = QChar::LineSeparator;
            return text;
        }

    static QString valueToText(const QVariant &value, const QStyleOptionViewItemV3 &option);

    void _q_commitDataAndCloseEditor(QWidget *editor);

    QItemEditorFactory *f;
    bool clipPainting;

    QRect textLayoutBounds(const QStyleOptionViewItemV2 &options) const;
    QSizeF doTextLayout(int lineWidth) const;
    mutable QTextLayout textLayout;
    mutable QTextOption textOption;

    const QWidget *widget(const QStyleOptionViewItem &option) const
    {
        if (const QStyleOptionViewItemV3 *v3 = qstyleoption_cast<const QStyleOptionViewItemV3 *>(&option))
            return v3->widget;

        return 0;
    }

    // ### temporary hack until we have QStandardItemDelegate
    mutable struct Icon {
        QIcon icon;
        QIcon::Mode mode;
        QIcon::State state;
    } tmp;
};

void QItemDelegatePrivate::_q_commitDataAndCloseEditor(QWidget *editor)
{
    Q_Q(QItemDelegate);
    emit q->commitData(editor);
    emit q->closeEditor(editor, QAbstractItemDelegate::SubmitModelCache);
}

QRect QItemDelegatePrivate::textLayoutBounds(const QStyleOptionViewItemV2 &option) const
{
    QRect rect = option.rect;
    const bool wrapText = option.features & QStyleOptionViewItemV2::WrapText;
    switch (option.decorationPosition) {
    case QStyleOptionViewItem::Left:
    case QStyleOptionViewItem::Right:
        rect.setWidth(wrapText && rect.isValid() ? rect.width() : (QFIXED_MAX));
        break;
    case QStyleOptionViewItem::Top:
    case QStyleOptionViewItem::Bottom:
        rect.setWidth(wrapText ? option.decorationSize.width() : (QFIXED_MAX));
        break;
    }

    return rect;
}

QSizeF QItemDelegatePrivate::doTextLayout(int lineWidth) const
{
    qreal height = 0;
    qreal widthUsed = 0;
    textLayout.beginLayout();
    while (true) {
        QTextLine line = textLayout.createLine();
        if (!line.isValid())
            break;
        line.setLineWidth(lineWidth);
        line.setPosition(QPointF(0, height));
        height += line.height();
        widthUsed = qMax(widthUsed, line.naturalTextWidth());
    }
    textLayout.endLayout();
    return QSizeF(widthUsed, height);
}

/*!
    \class QItemDelegate

    \brief The QItemDelegate class provides display and editing facilities for
    data items from a model.

    \ingroup model-view
    \mainclass

    QItemDelegate can be used to provide custom display features and editor
    widgets for item views based on QAbstractItemView subclasses. Using a
    delegate for this purpose allows the display and editing mechanisms to be
    customized and developed independently from the model and view.

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

    When displaying items from a custom model in a standard view, it is
    often sufficient to simply ensure that the model returns appropriate
    data for each of the \l{Qt::ItemDataRole}{roles} that determine the
    appearance of items in views. The default delegate used by Qt's
    standard views uses this role information to display items in most
    of the common forms expected by users. However, it is sometimes
    necessary to have even more control over the appearance of items than
    the default delegate can provide.

    This class provides default implementations of the functions for
    painting item data in a view and editing data from item models.
    Default implementations of the paint() and sizeHint() virtual
    functions, defined in QAbstractItemDelegate, are provided to
    ensure that the delegate implements the correct basic behavior
    expected by views. You can reimplement these functions in
    subclasses to customize the appearance of items.

    When editing data in an item view, QItemDelegate provides an
    editor widget, which is a widget that is placed on top of the view
    while editing takes place. Editors are created with a
    QItemEditorFactory; a default static instance provided by
    QItemEditorFactory is installed on all item delagates. You can set
    a custom factory using setItemEditorFactory() or set a new default
    factory with QItemEditorFactory::setDefaultFactory(). It is the
    data stored in the item model with the Qt::EditRole that is edited.

    Only the standard editing functions for widget-based delegates are
    reimplemented here:

    \list
        \o createEditor() returns the widget used to change data from the model
           and can be reimplemented to customize editing behavior.
        \o setEditorData() provides the widget with data to manipulate.
        \o updateEditorGeometry() ensures that the editor is displayed correctly
           with respect to the item view.
        \o setModelData() returns updated data to the model.
    \endlist

    The closeEditor() signal indicates that the user has completed editing the data,
    and that the editor widget can be destroyed.

    \section1 Standard Roles and Data Types

    The default delegate used by the standard views supplied with Qt
    associates each standard role (defined by Qt::ItemDataRole) with certain
    data types. Models that return data in these types can influence the
    appearance of the delegate as described in the following table.

    \table
    \header \o Role \o Accepted Types
    \omit
    \row    \o \l Qt::AccessibleDescriptionRole \o QString
    \row    \o \l Qt::AccessibleTextRole \o QString
    \endomit
    \row    \o \l Qt::BackgroundRole \o QBrush
    \row    \o \l Qt::BackgroundColorRole \o QColor (obsolete; use Qt::BackgroundRole instead)
    \row    \o \l Qt::CheckStateRole \o Qt::CheckState
    \row    \o \l Qt::DecorationRole \o QIcon and QColor
    \row    \o \l Qt::DisplayRole \o QString and types with a string representation
    \row    \o \l Qt::EditRole \o See QItemEditorFactory for details
    \row    \o \l Qt::FontRole \o QFont
    \row    \o \l Qt::SizeHintRole \o QSize
    \omit
    \row    \o \l Qt::StatusTipRole \o
    \endomit
    \row    \o \l Qt::TextAlignmentRole \o Qt::Alignment
    \row    \o \l Qt::ForegroundRole \o QBrush
    \row    \o \l Qt::TextColorRole \o QColor (obsolete; use Qt::ForegroundRole instead)
    \omit
    \row    \o \l Qt::ToolTipRole
    \row    \o \l Qt::WhatsThisRole
    \endomit
    \endtable

    If the default delegate does not allow the level of customization that
    you need, either for display purposes or for editing data, it is possible to
    subclass QItemDelegate to implement the desired behavior.

    \section1 Subclassing

    When subclassing QItemDelegate to create a delegate that displays items
    using a custom renderer, it is important to ensure that the delegate can
    render items suitably for all the required states; e.g. selected,
    disabled, checked. The documentation for the paint() function contains
    some hints to show how this can be achieved.

    You can provide custom editors by using a QItemEditorFactory. The
    \l{Color Editor Factory Example} shows how a custom editor can be
    made available to delegates with the default item editor
    factory. This way, there is no need to subclass QItemDelegate.  An
    alternative is to reimplement createEditor(), setEditorData(),
    setModelData(), and updateEditorGeometry(). This process is
    described in the \l{Spin Box Delegate example}.

    \sa {Delegate Classes}, QAbstractItemDelegate, {Spin Box Delegate Example},
        {Settings Editor Example}, {Icons Example}
*/

/*!
    Constructs an item delegate with the given \a parent.
*/

QItemDelegate::QItemDelegate(QObject *parent)
    : QAbstractItemDelegate(*new QItemDelegatePrivate(), parent)
{

}

/*!
    Destroys the item delegate.
*/

QItemDelegate::~QItemDelegate()
{
}

/*!
  \property QItemDelegate::clipping
  \brief if the delegate should clip the paint events
  \since 4.2

  This property will set the paint clip to the size of the item.
  The default value is on. It is useful for cases such
  as when images are larger then the size of the item.
*/

bool QItemDelegate::hasClipping() const
{
    Q_D(const QItemDelegate);
    return d->clipPainting;
}

void QItemDelegate::setClipping(bool clip)
{
    Q_D(QItemDelegate);
    d->clipPainting = clip;
}