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Internal/Contributor docs for the Qt SDK. Note: These are NOT official API docs; those are found at https://doc.qt.io/
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QStyledItemDelegate Class Reference

The QStyledItemDelegate class provides display and editing facilities for data items from a model. More...

#include <qstyleditemdelegate.h>

+ Inheritance diagram for QStyledItemDelegate:
+ Collaboration diagram for QStyledItemDelegate:

Public Member Functions

 QStyledItemDelegate (QObject *parent=nullptr)
 Constructs an item delegate with the given parent.
 
 ~QStyledItemDelegate ()
 Destroys the item delegate.
 
void paint (QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override
 Renders the delegate using the given painter and style option for the item specified by index.
 
QSize sizeHint (const QStyleOptionViewItem &option, const QModelIndex &index) const override
 Returns the size needed by the delegate to display the item specified by index, taking into account the style information provided by option.
 
QWidgetcreateEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const override
 Returns the widget used to edit the item specified by index for editing.
 
void setEditorData (QWidget *editor, const QModelIndex &index) const override
 Sets the data to be displayed and edited by the editor from the data model item specified by the model index.
 
void setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const override
 Gets data from the editor widget and stores it in the specified model at the item index.
 
void updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const override
 Updates the editor for the item specified by index according to the style option given.
 
QItemEditorFactoryitemEditorFactory () const
 Returns the editor factory used by the item delegate.
 
void setItemEditorFactory (QItemEditorFactory *factory)
 Sets the editor factory to be used by the item delegate to be the factory specified.
 
virtual QString displayText (const QVariant &value, const QLocale &locale) const
 This function returns the string that the delegate will use to display the Qt::DisplayRole of the model in locale.
 
- Public Member Functions inherited from QAbstractItemDelegate
 QAbstractItemDelegate (QObject *parent=nullptr)
 Creates a new abstract item delegate with the given parent.
 
virtual ~QAbstractItemDelegate ()
 Destroys the abstract item delegate.
 
virtual void destroyEditor (QWidget *editor, const QModelIndex &index) const
 Called when the editor is no longer needed for editing the data item with the given index and should be destroyed.
 
virtual bool helpEvent (QHelpEvent *event, QAbstractItemView *view, const QStyleOptionViewItem &option, const QModelIndex &index)
 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.
 
virtual QList< int > paintingRoles () const
 
- Public Member Functions inherited from QObject
Q_INVOKABLE QObject (QObject *parent=nullptr)
 Constructs an object with parent object parent.
 
virtual ~QObject ()
 Destroys the object, deleting all its child objects.
 
virtual bool event (QEvent *event)
 This virtual function receives events to an object and should return true if the event e was recognized and processed.
 
QString objectName () const
 
Q_WEAK_OVERLOAD void setObjectName (const QString &name)
 Sets the object's name to name.
 
void setObjectName (QAnyStringView name)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
QBindable< QStringbindableObjectName ()
 
bool isWidgetType () const
 Returns true if the object is a widget; otherwise returns false.
 
bool isWindowType () const
 Returns true if the object is a window; otherwise returns false.
 
bool isQuickItemType () const
 Returns true if the object is a QQuickItem; otherwise returns false.
 
bool signalsBlocked () const noexcept
 Returns true if signals are blocked; otherwise returns false.
 
bool blockSignals (bool b) noexcept
 If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
 
QThreadthread () const
 Returns the thread in which the object lives.
 
bool moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
 Changes the thread affinity for this object and its children and returns true on success.
 
int startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
 This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
 
int startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
 
void killTimer (int id)
 Kills the timer with timer identifier, id.
 
void killTimer (Qt::TimerId id)
 
template<typename T >
findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
 
template<typename T >
QList< T > findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
 
template<typename T >
findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
template<typename T >
QList< T > findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
const QObjectListchildren () const
 Returns a list of child objects.
 
void setParent (QObject *parent)
 Makes the object a child of parent.
 
void installEventFilter (QObject *filterObj)
 Installs an event filter filterObj on this object.
 
void removeEventFilter (QObject *obj)
 Removes an event filter object obj from this object.
 
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
 Dumps a tree of children to the debug output.
 
void dumpObjectInfo () const
 Dumps information about signal connections, etc.
 
bool setProperty (const char *name, const QVariant &value)
 Sets the value of the object's name property to value.
 
bool setProperty (const char *name, QVariant &&value)
 
QVariant property (const char *name) const
 Returns the value of the object's name property.
 
QList< QByteArraydynamicPropertyNames () const
 
QBindingStoragebindingStorage ()
 
const QBindingStoragebindingStorage () const
 
QObjectparent () const
 Returns a pointer to the parent object.
 
bool inherits (const char *classname) const
 Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.
 

Protected Member Functions

virtual void initStyleOption (QStyleOptionViewItem *option, const QModelIndex &index) const
 Initialize option with the values using the index index.
 
bool eventFilter (QObject *object, QEvent *event) override
 Returns true if the given editor is a valid QWidget and the given event is handled; otherwise returns false.
 
bool editorEvent (QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index) override
 \reimp
 
- Protected Member Functions inherited from QAbstractItemDelegate
 QAbstractItemDelegate (QObjectPrivate &, QObject *parent=nullptr)
 
- Protected Member Functions inherited from QObject
QObjectsender () const
 Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
 
int senderSignalIndex () const
 
int receivers (const char *signal) const
 Returns the number of receivers connected to the signal.
 
bool isSignalConnected (const QMetaMethod &signal) const
 
virtual void timerEvent (QTimerEvent *event)
 This event handler can be reimplemented in a subclass to receive timer events for the object.
 
virtual void childEvent (QChildEvent *event)
 This event handler can be reimplemented in a subclass to receive child events.
 
virtual void customEvent (QEvent *event)
 This event handler can be reimplemented in a subclass to receive custom events.
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
 QObject (QObjectPrivate &dd, QObject *parent=nullptr)
 

Additional Inherited Members

- Public Types inherited from QAbstractItemDelegate
enum  EndEditHint {
  NoHint , EditNextItem , EditPreviousItem , SubmitModelCache ,
  RevertModelCache
}
 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. More...
 
- Public Slots inherited from QObject
void deleteLater ()
 \threadsafe
 
- Signals inherited from QAbstractItemDelegate
void commitData (QWidget *editor)
 This signal must be emitted when the editor widget has completed editing the data, and wants to write it back into the model.
 
void closeEditor (QWidget *editor, QAbstractItemDelegate::EndEditHint hint=NoHint)
 This signal is emitted when the user has finished editing an item using the specified editor.
 
void sizeHintChanged (const QModelIndex &)
 This signal must be emitted when the sizeHint() of index changed.
 
- Signals inherited from QObject
void destroyed (QObject *=nullptr)
 This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
 
void objectNameChanged (const QString &objectName, QPrivateSignal)
 This signal is emitted after the object's name has been changed.
 
- 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)
 \threadsafe
 
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::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
 
static bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
 \threadsafe
 
static bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
 
static bool disconnect (const QMetaObject::Connection &)
 Disconnect a 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< QObjectDatad_ptr
 
- Properties inherited from QObject
QString objectName
 the name of this object
 

Detailed Description

The QStyledItemDelegate class provides display and editing facilities for data items from a model.

\inmodule QtWidgets

When displaying data from models in Qt item views, e.g., a QTableView, the individual items are drawn by a delegate. Also, when an item is edited, it provides an editor widget, which is placed on top of the item view while editing takes place. QStyledItemDelegate is the default delegate for all Qt item views, and is installed upon them when they are created.

The QStyledItemDelegate class is one of the \l{Model/View Classes} and is part of Qt's \l{Model/View Programming}{model/view framework}. The delegate allows the display and editing of items to be developed independently from the model and view.

The data of items in models are assigned an \l{Qt::}{ItemDataRole}; each item can store a QVariant for each role. QStyledItemDelegate implements display and editing for the most common datatypes expected by users, including booleans, integers, and strings.

The data will be drawn differently depending on which role they have in the model. The following table describes the roles and the data types the delegate can handle for each of them. It is often sufficient to ensure that the model returns appropriate data for each of the roles to determine the appearance of items in views.

\table \header

Editors are created with a QItemEditorFactory; a default static instance provided by QItemEditorFactory is installed on all item delegates. You can set a custom factory using setItemEditorFactory() or set a new default factory with QItemEditorFactory::setDefaultFactory().

After the new factory has been set, all standard item delegates will use it (i.e, also delegates that were created before the new default factory was set).

It is the data stored in the item model with the \l{Qt::}{EditRole} that is edited. See the QItemEditorFactory class for a more high-level introduction to item editor factories.

Definition at line 20 of file qstyleditemdelegate.h.

Constructor & Destructor Documentation

◆ QStyledItemDelegate()

QStyledItemDelegate::QStyledItemDelegate ( QObject * parent = nullptr)
explicit

Constructs an item delegate with the given parent.

Definition at line 217 of file qstyleditemdelegate.cpp.

◆ ~QStyledItemDelegate()

QStyledItemDelegate::~QStyledItemDelegate ( )

Destroys the item delegate.

Definition at line 225 of file qstyleditemdelegate.cpp.

Member Function Documentation

◆ createEditor()

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

Returns the widget used to edit the item specified by index for editing.

The parent widget and style option are used to control how the editor widget appears.

See also
QAbstractItemDelegate::createEditor()

Reimplemented from QAbstractItemDelegate.

Reimplemented in qdesigner_internal::WidgetBoxCategoryEntryDelegate, qdesigner_internal::WidgetBoxCategoryEntryDelegate, SpinBoxDelegate, and SpinBoxDelegate.

Definition at line 410 of file qstyleditemdelegate.cpp.

◆ displayText()

QString QStyledItemDelegate::displayText ( const QVariant & value,
const QLocale & locale ) const
virtual

This function returns the string that the delegate will use to display the Qt::DisplayRole of the model in locale.

value is the value of the Qt::DisplayRole provided by the model.

The default implementation uses the QLocale::toString to convert value into a QString.

This function is not called for empty model indices, i.e., indices for which the model returns an invalid QVariant.

See also
QAbstractItemModel::data()

Definition at line 242 of file qstyleditemdelegate.cpp.

◆ editorEvent()

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

\reimp

Reimplemented from QAbstractItemDelegate.

Definition at line 555 of file qstyleditemdelegate.cpp.

◆ eventFilter()

bool QStyledItemDelegate::eventFilter ( QObject * editor,
QEvent * event )
overrideprotectedvirtual

Returns true if the given editor is a valid QWidget and the given event is handled; otherwise returns false.

The following key press events are handled by default:

\list

  • \uicontrol Tab
  • \uicontrol Backtab
  • \uicontrol Enter
  • \uicontrol Return
  • \uicontrol Esc \endlist

If the editor's type is QTextEdit or QPlainTextEdit then \uicontrol Tab, \uicontrol Backtab, \uicontrol Enter and \uicontrol Return keys are not handled.

In the case of \uicontrol Tab, \uicontrol Backtab, \uicontrol Enter and \uicontrol Return key press events, the editor's data is committed to the model and the editor is closed. If the event is a \uicontrol Tab key press the view will open an editor on the next item in the view. Likewise, if the event is a \uicontrol Backtab key press the view will open an editor on the previous item in the view.

If the event is a \uicontrol Esc key press event, the editor is closed without committing its data.

See also
commitData(), closeEditor()

Reimplemented from QObject.

Definition at line 546 of file qstyleditemdelegate.cpp.

◆ initStyleOption()

void QStyledItemDelegate::initStyleOption ( QStyleOptionViewItem * option,
const QModelIndex & index ) const
protectedvirtual

Initialize option with the values using the index index.

This method is useful for subclasses when they need a QStyleOptionViewItem, but don't want to fill in all the information themselves.

See also
QStyleOption::initFrom()

Reimplemented in QSideBarDelegate.

Definition at line 254 of file qstyleditemdelegate.cpp.

◆ itemEditorFactory()

QItemEditorFactory * QStyledItemDelegate::itemEditorFactory ( ) const

Returns the editor factory used by the item delegate.

If no editor factory is set, the function will return null.

See also
setItemEditorFactory()

Definition at line 495 of file qstyleditemdelegate.cpp.

◆ paint()

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

Renders the delegate using the given painter and style option for the item specified by index.

This function paints the item using the view's QStyle.

When reimplementing paint in a subclass. Use the initStyleOption() to set up the option in the same way as the QStyledItemDelegate.

Whenever possible, use the option while painting. Especially its \l{QStyleOption::}{rect} variable to decide where to draw and its \l{QStyleOption::}{state} to determine if it is enabled or selected.

After painting, you should ensure that the painter is returned to the state it was supplied in when this function was called. For example, it may be useful to call QPainter::save() before painting and QPainter::restore() afterwards.

See also
QItemDelegate::paint(), QStyle::drawControl(), QStyle::CE_ItemViewItem

Implements QAbstractItemDelegate.

Reimplemented in qdesigner_internal::SheetDelegate.

Definition at line 366 of file qstyleditemdelegate.cpp.

◆ setEditorData()

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

Sets the data to be displayed and edited by the editor from the data model item specified by the model index.

The default implementation stores the data in the editor widget's \l {Qt's Property System} {user property}.

See also
QMetaProperty::isUser()

Reimplemented from QAbstractItemDelegate.

Reimplemented in SpinBoxDelegate, and SpinBoxDelegate.

Definition at line 430 of file qstyleditemdelegate.cpp.

◆ setItemEditorFactory()

void QStyledItemDelegate::setItemEditorFactory ( QItemEditorFactory * factory)

Sets the editor factory to be used by the item delegate to be the factory specified.

If no editor factory is set, the item delegate will use the default editor factory.

See also
itemEditorFactory()

Definition at line 508 of file qstyleditemdelegate.cpp.

◆ setModelData()

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

Gets data from the editor widget and stores it in the specified model at the item index.

The default implementation gets the value to be stored in the data model from the editor widget's \l {Qt's Property System} {user property}.

See also
QMetaProperty::isUser()

Reimplemented from QAbstractItemDelegate.

Reimplemented in SpinBoxDelegate, and SpinBoxDelegate.

Definition at line 452 of file qstyleditemdelegate.cpp.

◆ sizeHint()

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

Returns the size needed by the delegate to display the item specified by index, taking into account the style information provided by option.

This function uses the view's QStyle to determine the size of the item.

See also
QStyle::sizeFromContents(), QStyle::CT_ItemViewItem

Implements QAbstractItemDelegate.

Reimplemented in qdesigner_internal::SheetDelegate.

Definition at line 389 of file qstyleditemdelegate.cpp.

◆ updateEditorGeometry()

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

Updates the editor for the item specified by index according to the style option given.

Reimplemented from QAbstractItemDelegate.

Reimplemented in SpinBoxDelegate, and SpinBoxDelegate.

Definition at line 471 of file qstyleditemdelegate.cpp.


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