/**************************************************************************** ** ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the QtGui module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** No Commercial Usage ** This file contains pre-release code and may not be distributed. ** You may use this file in accordance with the terms and conditions ** contained in the Technology Preview License Agreement accompanying ** this package. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 2.1 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 2.1 requirements ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. ** ** In addition, as a special exception, Nokia gives you certain additional ** rights. These rights are described in the Nokia Qt LGPL Exception ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. ** ** If you have questions regarding the use of this file, please contact ** Nokia at qt-info@nokia.com. ** ** ** ** ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qabstractitemdelegate.h" #ifndef QT_NO_ITEMVIEWS #include #include #include #include #include #include #include #include #include QT_BEGIN_NAMESPACE /*! \class QAbstractItemDelegate \brief The QAbstractItemDelegate class is used to display and edit data items from a model. \ingroup model-view \mainclass 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(event); QVariant tooltip = index.data(Qt::ToolTipRole); if (qVariantCanConvert(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(event); QVariant whatsthis = index.data(Qt::WhatsThisRole); if (qVariantCanConvert(whatsthis)) { QWhatsThis::showText(he->globalPos(), whatsthis.toString(), view); return true; } break ; } #endif default: break; } return false; } QT_END_NAMESPACE #endif // QT_NO_ITEMVIEWS