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#include "qabstractitemdelegate.h"
#ifndef QT_NO_ITEMVIEWS
#include <qabstractitemmodel.h>
#include <qabstractitemview.h>
#include <qfontmetrics.h>
#include <qwhatsthis.h>
#include <qtooltip.h>
#include <qevent.h>
#include <qstring.h>
#include <qdebug.h>
#include <private/qtextengine_p.h>
QT_BEGIN_NAMESPACE
/*!
\class QAbstractItemDelegate
\brief The QAbstractItemDelegate class is used to display and edit
data items from a model.
\ingroup model-view
A QAbstractItemDelegate provides the interface and common functionality
for delegates in the model/view architecture. Delegates display
individual items in views, and handle the editing of model data.
The QAbstractItemDelegate class is one of the \l{Model/View Classes}
and is part of Qt's \l{Model/View Programming}{model/view framework}.
To render an item in a custom way, you must implement paint() and
sizeHint(). The QItemDelegate class provides default implementations for
these functions; if you do not need custom rendering, subclass that
class instead.
We give an example of drawing a progress bar in items; in our case
for a package management program.
\image widgetdelegate.png
We create the \c WidgetDelegate class, which inherits from
QStyledItemDelegate. We do the drawing in the paint() function:
\snippet doc/src/snippets/widgetdelegate.cpp 0
Notice that we use a QStyleOptionProgressBar and initialize its
members. We can then use the current QStyle to draw it.
To provide custom editing, there are two approaches that can be
used. The first approach is to create an editor widget and display
it directly on top of the item. To do this you must reimplement
createEditor() to provide an editor widget, setEditorData() to populate
the editor with the data from the model, and setModelData() so that the
delegate can update the model with data from the editor.
The second approach is to handle user events directly by reimplementing
editorEvent().
\sa {model-view-programming}{Model/View Programming}, QItemDelegate,
{Pixelator Example}, QStyledItemDelegate, QStyle
*/
/*!
\enum QAbstractItemDelegate::EndEditHint
This enum describes the different hints that the delegate can give to the
model and view components to make editing data in a model a comfortable
experience for the user.
\value NoHint There is no recommended action to be performed.
These hints let the delegate influence the behavior of the view:
\value EditNextItem The view should use the delegate to open an
editor on the next item in the view.
\value EditPreviousItem The view should use the delegate to open an
editor on the previous item in the view.
Note that custom views may interpret the concepts of next and previous
differently.
The following hints are most useful when models are used that cache
data, such as those that manipulate data locally in order to increase
performance or conserve network bandwidth.
\value SubmitModelCache If the model caches data, it should write out
cached data to the underlying data store.
\value RevertModelCache If the model caches data, it should discard
cached data and replace it with data from the
underlying data store.
Although models and views should respond to these hints in appropriate
ways, custom components may ignore any or all of them if they are not
relevant.
*/
/*!
\fn void QAbstractItemDelegate::commitData(QWidget *editor)
This signal must be emitted when the \a editor widget has completed
editing the data, and wants to write it back into the model.
*/
/*!
\fn void QAbstractItemDelegate::closeEditor(QWidget *editor, QAbstractItemDelegate::EndEditHint hint)
This signal is emitted when the user has finished editing an item using
the specified \a editor.
The \a hint provides a way for the delegate to influence how the model and
view behave after editing is completed. It indicates to these components
what action should be performed next to provide a comfortable editing
experience for the user. For example, if \c EditNextItem is specified,
the view should use a delegate to open an editor on the next item in the
model.
\sa EndEditHint
*/
/*!
\fn void QAbstractItemDelegate::sizeHintChanged(const QModelIndex &index)
\since 4.4
This signal must be emitted when the sizeHint() of \a index changed.
Views automatically connect to this signal and relayout items as necessary.
*/
/*!
Creates a new abstract item delegate with the given \a parent.
*/
QAbstractItemDelegate::QAbstractItemDelegate(QObject *parent)
: QObject(parent)
{
}
/*!
\internal
Creates a new abstract item delegate with the given \a parent.
*/
QAbstractItemDelegate::QAbstractItemDelegate(QObjectPrivate &dd, QObject *parent)
: QObject(dd, parent)
{
}
/*!
Destroys the abstract item delegate.
*/
QAbstractItemDelegate::~QAbstractItemDelegate()
{
}
/*!
\fn void QAbstractItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const = 0;
This pure abstract function must be reimplemented if you want to
provide custom rendering. Use the \a painter and style \a option to
render the item specified by the item \a index.
If you reimplement this you must also reimplement sizeHint().
*/
/*!
\fn QSize QAbstractItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const = 0
This pure abstract function must be reimplemented if you want to
provide custom rendering. The options are specified by \a option
and the model item by \a index.
If you reimplement this you must also reimplement paint().
*/
/*!
Returns the editor to be used for editing the data item with the
given \a index. Note that the index contains information about the
model being used. The editor's parent widget is specified by \a parent,
and the item options by \a option.
The base implementation returns 0. If you want custom editing you
will need to reimplement this function.
The returned editor widget should have Qt::StrongFocus;
otherwise, \l{QMouseEvent}s received by the widget will propagate
to the view. The view's background will shine through unless the
editor paints its own background (e.g., with
\l{QWidget::}{setAutoFillBackground()}).
\sa setModelData() setEditorData()
*/
QWidget *QAbstractItemDelegate::createEditor(QWidget *,
const QStyleOptionViewItem &,
const QModelIndex &) const
{
return 0;
}
/*!
Sets the contents of the given \a editor to the data for the item
at the given \a index. Note that the index contains information
about the model being used.
The base implementation does nothing. If you want custom editing
you will need to reimplement this function.
\sa setModelData()
*/
void QAbstractItemDelegate::setEditorData(QWidget *,
const QModelIndex &) const
{
// do nothing
}
/*!
Sets the data for the item at the given \a index in the \a model
to the contents of the given \a editor.
The base implementation does nothing. If you want custom editing
you will need to reimplement this function.
\sa setEditorData()
*/
void QAbstractItemDelegate::setModelData(QWidget *,
QAbstractItemModel *,
const QModelIndex &) const
{
// do nothing
}
/*!
Updates the geometry of the \a editor for the item with the given
\a index, according to the rectangle specified in the \a option.
If the item has an internal layout, the editor will be laid out
accordingly. Note that the index contains information about the
model being used.
The base implementation does nothing. If you want custom editing
you must reimplement this function.
*/
void QAbstractItemDelegate::updateEditorGeometry(QWidget *,
const QStyleOptionViewItem &,
const QModelIndex &) const
{
// do nothing
}
/*!
Whenever an event occurs, this function is called with the \a event
\a model \a option and the \a index that corresponds to the item being edited.
The base implementation returns false (indicating that it has not
handled the event).
*/
bool QAbstractItemDelegate::editorEvent(QEvent *,
QAbstractItemModel *,
const QStyleOptionViewItem &,
const QModelIndex &)
{
// do nothing
return false;
}
/*!
\obsolete
Use QFontMetrics::elidedText() instead.
\oldcode
QFontMetrics fm = ...
QString str = QAbstractItemDelegate::elidedText(fm, width, mode, text);
\newcode
QFontMetrics fm = ...
QString str = fm.elidedText(text, mode, width);
\endcode
*/
QString QAbstractItemDelegate::elidedText(const QFontMetrics &fontMetrics, int width,
Qt::TextElideMode mode, const QString &text)
{
return fontMetrics.elidedText(text, mode, width);
}
/*!
\since 4.3
Whenever a help event occurs, this function is called with the \a event
\a view \a option and the \a index that corresponds to the item where the
event occurs.
Returns true if the delegate can handle the event; otherwise returns false.
A return value of true indicates that the data obtained using the index had
the required role.
For QEvent::ToolTip and QEvent::WhatsThis events that were handled successfully,
the relevant popup may be shown depending on the user's system configuration.
\sa QHelpEvent
*/
// ### Qt 5: Make this a virtual non-slot function
bool QAbstractItemDelegate::helpEvent(QHelpEvent *event,
QAbstractItemView *view,
const QStyleOptionViewItem &option,
const QModelIndex &index)
{
Q_UNUSED(option);
if (!event || !view)
return false;
switch (event->type()) {
#ifndef QT_NO_TOOLTIP
case QEvent::ToolTip: {
QHelpEvent *he = static_cast<QHelpEvent*>(event);
QVariant tooltip = index.data(Qt::ToolTipRole);
if (qVariantCanConvert<QString>(tooltip)) {
QToolTip::showText(he->globalPos(), tooltip.toString(), view);
return true;
}
break;}
#endif
#ifndef QT_NO_WHATSTHIS
case QEvent::QueryWhatsThis: {
if (index.data(Qt::WhatsThisRole).isValid())
return true;
break; }
case QEvent::WhatsThis: {
QHelpEvent *he = static_cast<QHelpEvent*>(event);
QVariant whatsthis = index.data(Qt::WhatsThisRole);
if (qVariantCanConvert<QString>(whatsthis)) {
QWhatsThis::showText(he->globalPos(), whatsthis.toString(), view);
return true;
}
break ; }
#endif
default:
break;
}
return false;
}
QT_END_NAMESPACE
#endif // QT_NO_ITEMVIEWS