The QAbstractItemDelegate class is used to display and edit data items from a model. More...

#include <qabstractitemdelegate.h>

Inheritance diagram for QAbstractItemDelegate:

Collaboration diagram for QAbstractItemDelegate:

Public Types
enum	EndEditHint { NoHint , EditNextItem , EditPreviousItem , SubmitModelCache , RevertModelCache }

Signals
void	commitData (QWidget *editor)

void	closeEditor (QWidget *editor, QAbstractItemDelegate::EndEditHint hint=NoHint)

void	sizeHintChanged (const QModelIndex &)

Signals inherited from QObject
void	destroyed (QObject *=nullptr)

void	objectNameChanged (const QString &objectName, QPrivateSignal)

Public Member Functions
	QAbstractItemDelegate (QObject *parent=nullptr)

virtual	~QAbstractItemDelegate ()

virtual void	paint (QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const =0

virtual QSize	sizeHint (const QStyleOptionViewItem &option, const QModelIndex &index) const =0

virtual QWidget *	createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const

virtual void	destroyEditor (QWidget *editor, const QModelIndex &index) const

virtual void	setEditorData (QWidget *editor, const QModelIndex &index) const

virtual void	setModelData (QWidget editor, QAbstractItemModel model, const QModelIndex &index) const

virtual void	updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const

virtual bool	editorEvent (QEvent event, QAbstractItemModel model, const QStyleOptionViewItem &option, const QModelIndex &index)

virtual bool	helpEvent (QHelpEvent event, QAbstractItemView view, const QStyleOptionViewItem &option, const QModelIndex &index)

virtual QList< int >	paintingRoles () const

Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)

virtual	~QObject ()

virtual bool	event (QEvent *event)

virtual bool	eventFilter (QObject watched, QEvent event)

QString	objectName () const

void	setObjectName (const QString &name)

QBindable< QString >	bindableObjectName ()

bool	isWidgetType () const

bool	isWindowType () const

bool	signalsBlocked () const noexcept

bool	blockSignals (bool b) noexcept

QThread *	thread () const

void	moveToThread (QThread *thread)

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)

template<typename T >
T	findChild (const QString &aName=QString(), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<typename T >
QList< T >	findChildren (const QString &aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

const QObjectList &	children () const

void	setParent (QObject *parent)

void	installEventFilter (QObject *filterObj)

void	removeEventFilter (QObject *obj)

QMetaObject::Connection	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=nullptr, const QObject receiver=nullptr, const char *member=nullptr) const

bool	disconnect (const QObject receiver, const char member=nullptr) const

void	dumpObjectTree () const

void	dumpObjectInfo () const

bool	setProperty (const char *name, const QVariant &value)

QVariant	property (const char *name) const

QList< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () const

bool	inherits (const char *classname) const

Protected Member Functions
	QAbstractItemDelegate (QObjectPrivate &, QObject *parent=nullptr)

Protected Member Functions inherited from QObject
QObject *	sender () const

int	senderSignalIndex () const

int	receivers (const char *signal) const

bool	isSignalConnected (const QMetaMethod &signal) const

virtual void	timerEvent (QTimerEvent *event)

virtual void	childEvent (QChildEvent *event)

virtual void	customEvent (QEvent *event)

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	disconnectNotify (const QMetaMethod &signal)

	QObject (QObjectPrivate &dd, QObject *parent=nullptr)

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()

Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)

static QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object receiver, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

static QMetaObject::Connection ::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 slot)

static QMetaObject::Connection ::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject context, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static std::enable_if< QtPrivate::FunctionPointer< Func2 >::ArgumentCount==-1 &&!std::is_convertible_v< Func2, const char * >, QMetaObject::Connection >::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 slot)

template<typename Func1 , typename Func2 >
static std::enable_if< QtPrivate::FunctionPointer< Func2 >::ArgumentCount==-1 &&!std::is_convertible_v< Func2, const char * >, QMetaObject::Connection >::type	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject context, Func2 slot, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static bool	disconnect (const QMetaObject::Connection &)

template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object receiver, Func2 slot)

template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject receiver, void **zero)

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Properties inherited from QObject
QString	objectName
	the name of this object More...

Related Functions inherited from QObject
template< class T > T	qobject_cast (const QObject *object)

template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

	QObjectList

Detailed Description

The QAbstractItemDelegate class is used to display and edit data items from a model.

\inmodule QtWidgets

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 QStyledItemDelegate 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.

We create the WidgetDelegate class, which inherits from QStyledItemDelegate. We do the drawing in the paint() function:

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().

See also: {model-view-programming}{Model/View Programming}, QStyledItemDelegate, {Pixelator Example}, QStyledItemDelegate, QStyle

Definition at line 58 of file qabstractitemdelegate.h.

Member Enumeration Documentation

◆ EndEditHint

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.

Enumerator
NoHint
EditNextItem
EditPreviousItem
SubmitModelCache
RevertModelCache

Definition at line 64 of file qabstractitemdelegate.h.

Constructor & Destructor Documentation

◆ QAbstractItemDelegate() [1/2]

QAbstractItemDelegate::QAbstractItemDelegate ( QObject * parent = nullptr )

explicit

Creates a new abstract item delegate with the given parent.

Definition at line 194 of file qabstractitemdelegate.cpp.

◆ ~QAbstractItemDelegate()

QAbstractItemDelegate::~QAbstractItemDelegate ( )

virtual

Destroys the abstract item delegate.

Definition at line 214 of file qabstractitemdelegate.cpp.

◆ QAbstractItemDelegate() [2/2]

QAbstractItemDelegate::QAbstractItemDelegate	(	QObjectPrivate &	dd,
		QObject *	parent = `nullptr`
	)

protected

Definition at line 205 of file qabstractitemdelegate.cpp.

Member Function Documentation

◆ closeEditor

void QAbstractItemDelegate::closeEditor	(	QWidget *	editor,
		QAbstractItemDelegate::EndEditHint	hint = `NoHint`
	)

signal

This signal is emitted when the user has finished editing an item using the specified editor.

The 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 EditNextItem is specified, the view should use a delegate to open an editor on the next item in the model.

See also: EndEditHint

◆ commitData

void QAbstractItemDelegate::commitData ( QWidget * editor )

signal

This signal must be emitted when the editor widget has completed editing the data, and wants to write it back into the model.

◆ createEditor()

QWidget * QAbstractItemDelegate::createEditor	(	QWidget *	parent,
		const QStyleOptionViewItem &	option,
		const QModelIndex &	index
	)		const

virtual

Returns the editor to be used for editing the data item with the given index. Note that the index contains information about the model being used. The editor's parent widget is specified by parent, and the item options by option.

The base implementation returns \nullptr. 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()}).

See also: destroyEditor(), setModelData(), setEditorData()

Reimplemented in QStyledItemDelegate, QItemDelegate, ImageDelegate, VariantDelegate, StarDelegate, SpinBoxDelegate, ChooseEditorDelegate, SpreadSheetDelegate, ItemDelegate, EditorItemDelegate, DialogItemDelegate, MyAbstractItemDelegate, and ExampleDelegate.

Definition at line 256 of file qabstractitemdelegate.cpp.

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◆ destroyEditor()

void QAbstractItemDelegate::destroyEditor	(	QWidget *	editor,
		const QModelIndex &	index
	)		const

virtual

Called when the editor is no longer needed for editing the data item with the given index and should be destroyed. The default behavior is a call to deleteLater on the editor. It is possible e.g. to avoid this delete by reimplementing this function.

Since: 5.0

See also: createEditor()

Reimplemented in ChooseEditorDelegate, MyAbstractItemDelegate, and ExampleDelegate.

Definition at line 273 of file qabstractitemdelegate.cpp.

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◆ editorEvent()

bool QAbstractItemDelegate::editorEvent	(	QEvent *	event,
		QAbstractItemModel *	model,
		const QStyleOptionViewItem &	option,
		const QModelIndex &	index
	)

virtual

When editing of an item starts, this function is called with the event that triggered the editing, the model, the index of the item, and the option used for rendering the item.

Mouse events are sent to editorEvent() even if they don't start editing of the item. This can, for instance, be useful if you wish to open a context menu when the right mouse button is pressed on an item.

The base implementation returns false (indicating that it has not handled the event).

Reimplemented in TestItemDelegate, QComboMenuDelegate, QStyledItemDelegate, and QItemDelegate.

Definition at line 341 of file qabstractitemdelegate.cpp.

◆ helpEvent()

bool QAbstractItemDelegate::helpEvent	(	QHelpEvent *	event,
		QAbstractItemView *	view,
		const QStyleOptionViewItem &	option,
		const QModelIndex &	index
	)

virtual

Since: 4.3 Whenever a help event occurs, this function is called with the event view option and the 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.

See also: QHelpEvent

Definition at line 365 of file qabstractitemdelegate.cpp.

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◆ paint()

void QAbstractItemDelegate::paint	(	QPainter *	painter,
		const QStyleOptionViewItem &	option,
		const QModelIndex &	index
	)		const

pure virtual

This pure abstract function must be reimplemented if you want to provide custom rendering. Use the painter and style option to render the item specified by the item index.

If you reimplement this you must also reimplement sizeHint().

Implemented in Delegate12308, QFontFamilyDelegate, QComboBoxDelegate, QComboMenuDelegate, QStyledItemDelegate, QItemDelegate, QColumnViewDelegate, VariantDelegate, StarDelegate, PixelDelegate, TorrentViewDelegate, HoverItemDelegate, QCompleterItemDelegate, MyAbstractItemDelegate, MyAbstractItemDelegate, and MyAbstractItemDelegate.

◆ paintingRoles()

QList< int > QAbstractItemDelegate::paintingRoles ( ) const

virtual

Definition at line 416 of file qabstractitemdelegate.cpp.

◆ setEditorData()

void QAbstractItemDelegate::setEditorData	(	QWidget *	editor,
		const QModelIndex &	index
	)		const

virtual

Sets the contents of the given editor to the data for the item at the given 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.

See also: setModelData()

Reimplemented in ExampleDelegate, StateChangeDelegate, QStyledItemDelegate, QItemDelegate, ImageDelegate, VariantDelegate, StarDelegate, SpreadSheetDelegate, and SpinBoxDelegate.

Definition at line 289 of file qabstractitemdelegate.cpp.

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◆ setModelData()

void QAbstractItemDelegate::setModelData	(	QWidget *	editor,
		QAbstractItemModel *	model,
		const QModelIndex &	index
	)		const

virtual

Sets the data for the item at the given index in the model to the contents of the given editor.

The base implementation does nothing. If you want custom editing you will need to reimplement this function.

See also: setEditorData()

Reimplemented in DialogItemDelegate, QStyledItemDelegate, QItemDelegate, ImageDelegate, VariantDelegate, StarDelegate, SpreadSheetDelegate, and SpinBoxDelegate.

Definition at line 304 of file qabstractitemdelegate.cpp.

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◆ sizeHint()

QSize QAbstractItemDelegate::sizeHint	(	const QStyleOptionViewItem &	option,
		const QModelIndex &	index
	)		const

pure virtual

This pure abstract function must be reimplemented if you want to provide custom rendering. The options are specified by option and the model item by index.

If you reimplement this you must also reimplement paint().

Implemented in QFontFamilyDelegate, QComboBoxDelegate, QComboMenuDelegate, QStyledItemDelegate, QItemDelegate, StarDelegate, PixelDelegate, MyAbstractItemDelegate, TestDelegate, QtTestItemDelegate, TestDelegate, MyAbstractItemDelegate, and MyAbstractItemDelegate.

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◆ sizeHintChanged

void QAbstractItemDelegate::sizeHintChanged ( const QModelIndex & index )

signal

Since: 4.4

This signal must be emitted when the sizeHint() of index changed.

Views automatically connect to this signal and relayout items as necessary.

◆ updateEditorGeometry()

void QAbstractItemDelegate::updateEditorGeometry	(	QWidget *	editor,
		const QStyleOptionViewItem &	option,
		const QModelIndex &	index
	)		const

virtual

Updates the geometry of the editor for the item with the given index, according to the rectangle specified in the 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.

Reimplemented in QStyledItemDelegate, QItemDelegate, and SpinBoxDelegate.

Definition at line 321 of file qabstractitemdelegate.cpp.

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The documentation for this class was generated from the following files:

src/widgets/itemviews/qabstractitemdelegate.h
src/widgets/itemviews/qabstractitemdelegate.cpp

Public Types

Signals

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ EndEditHint

Constructor & Destructor Documentation

◆ QAbstractItemDelegate() [1/2]

◆ ~QAbstractItemDelegate()

◆ QAbstractItemDelegate() [2/2]

Member Function Documentation

◆ closeEditor

◆ commitData

◆ createEditor()

◆ destroyEditor()

◆ editorEvent()

◆ helpEvent()

◆ paint()

◆ paintingRoles()

◆ setEditorData()

◆ setModelData()

◆ sizeHint()

◆ sizeHintChanged

◆ updateEditorGeometry()