The QUndoGroup class is a group of QUndoStack objects. More...

#include <qundogroup.h>

Inheritance diagram for QUndoGroup:

Collaboration diagram for QUndoGroup:

Public Slots
void	undo ()
	Calls QUndoStack::undo() on the active stack.

void	redo ()
	Calls QUndoStack::redo() on the active stack.

void	setActiveStack (QUndoStack *stack)
	Sets the active stack of this group to stack.

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	activeStackChanged (QUndoStack *stack)
	This signal is emitted whenever the active stack of the group changes.

void	indexChanged (int idx)
	This signal is emitted whenever the active stack emits QUndoStack::indexChanged() or the active stack changes.

void	cleanChanged (bool clean)
	This signal is emitted whenever the active stack emits QUndoStack::cleanChanged() or the active stack changes.

void	canUndoChanged (bool canUndo)
	This signal is emitted whenever the active stack emits QUndoStack::canUndoChanged() or the active stack changes.

void	canRedoChanged (bool canRedo)
	This signal is emitted whenever the active stack emits QUndoStack::canRedoChanged() or the active stack changes.

void	undoTextChanged (const QString &undoText)
	This signal is emitted whenever the active stack emits QUndoStack::undoTextChanged() or the active stack changes.

void	redoTextChanged (const QString &redoText)
	This signal is emitted whenever the active stack emits QUndoStack::redoTextChanged() or the active stack changes.

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.

Public Member Functions
	QUndoGroup (QObject *parent=nullptr)
	Creates an empty QUndoGroup object with parent parent.

	~QUndoGroup ()
	Destroys the QUndoGroup.

void	addStack (QUndoStack *stack)
	Adds stack to this group.

void	removeStack (QUndoStack *stack)
	Removes stack from this group.

QList< QUndoStack * >	stacks () const
	Returns a list of stacks in this group.

QUndoStack *	activeStack () const
	Returns the active stack of this group.

QAction *	createUndoAction (QObject *parent, const QString &prefix=QString()) const
	Creates an undo QAction object with parent parent.

QAction *	createRedoAction (QObject *parent, const QString &prefix=QString()) const
	Creates an redo QAction object with parent parent.

bool	canUndo () const
	Returns the value of the active stack's QUndoStack::canUndo().

bool	canRedo () const
	Returns the value of the active stack's QUndoStack::canRedo().

QString	undoText () const
	Returns the value of the active stack's QUndoStack::undoText().

QString	redoText () const
	Returns the value of the active stack's QUndoStack::redoText().

bool	isClean () const
	Returns the value of the active stack's QUndoStack::isClean().

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.

virtual bool	eventFilter (QObject watched, QEvent event)
	Filters events if this object has been installed as an event filter for the watched object.

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< QString >	bindableObjectName ()

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).

QThread *	thread () const
	Returns the thread in which the object lives.

void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children.

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::milliseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)
	Kills the timer with timer identifier, id.

template<typename T >
T	findChild (const QString &aName=QString(), 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 (const QString &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 >
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 QObjectList &	children () 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< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () 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`.

Additional Inherited Members
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 Member Functions inherited from QObject
QObject *	sender () 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)

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Properties inherited from QObject
QString	objectName
	the name of this object

Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.

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

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

	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

The QUndoGroup class is a group of QUndoStack objects.

Since: 4.2 \inmodule QtGui

For an overview of the Qt's undo framework, see the \l{qundo.html}{overview}.

An application often has multiple undo stacks, one for each opened document. At the same time, an application usually has one undo action and one redo action, which triggers undo or redo in the active document.

QUndoGroup is a group of QUndoStack objects, one of which may be active. It has an undo() and redo() slot, which calls QUndoStack::undo() and QUndoStack::redo() for the active stack. It also has the functions createUndoAction() and createRedoAction(). The actions returned by these functions behave in the same way as those returned by QUndoStack::createUndoAction() and QUndoStack::createRedoAction() of the active stack.

Stacks are added to a group with addStack() and removed with removeStack(). A stack is implicitly added to a group when it is created with the group as its parent QObject.

It is the programmer's responsibility to specify which stack is active by calling QUndoStack::setActive(), usually when the associated document window receives focus. The active stack may also be set with setActiveStack(), and is returned by activeStack().

When a stack is added to a group using addStack(), the group does not take ownership of the stack. This means the stack has to be deleted separately from the group. When a stack is deleted, it is automatically removed from a group. A stack may belong to only one group. Adding it to another group will cause it to be removed from the previous group.

A QUndoGroup is also useful in conjunction with QUndoView. If a QUndoView is set to watch a group using QUndoView::setGroup(), it will update itself to display the active stack.

Definition at line 19 of file qundogroup.h.

Constructor & Destructor Documentation

◆ QUndoGroup()

QUndoGroup::QUndoGroup ( QObject * parent = nullptr )

explicit

Creates an empty QUndoGroup object with parent parent.

See also: addStack()

Definition at line 65 of file qundogroup.cpp.

◆ ~QUndoGroup()

QUndoGroup::~QUndoGroup ( )

Destroys the QUndoGroup.

Definition at line 73 of file qundogroup.cpp.

References d, and it.

Member Function Documentation

◆ activeStack()

QUndoStack * QUndoGroup::activeStack ( ) const

Returns the active stack of this group.

If none of the stacks are active, or if the group is empty, this function returns \nullptr.

See also: setActiveStack(), QUndoStack::setActive()

Definition at line 214 of file qundogroup.cpp.

References d.

◆ activeStackChanged

void QUndoGroup::activeStackChanged ( QUndoStack * stack )

signal

This signal is emitted whenever the active stack of the group changes.

This can happen when setActiveStack() or QUndoStack::setActive() is called, or when the active stack is removed form the group. stack is the new active stack. If no stack is active, stack is 0.

See also: setActiveStack(), QUndoStack::setActive()

Referenced by setActiveStack().

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◆ addStack()

void QUndoGroup::addStack ( QUndoStack * stack )

Adds stack to this group.

The group does not take ownership of the stack. Another way of adding a stack to a group is by specifying the group as the stack's parent QObject in QUndoStack::QUndoStack(). In this case, the stack is deleted when the group is deleted, in the usual manner of QObjects.

See also: removeStack(), stacks(), QUndoStack::QUndoStack()

Definition at line 94 of file qundogroup.cpp.

References d, and other().

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◆ canRedo()

bool QUndoGroup::canRedo ( ) const

Returns the value of the active stack's QUndoStack::canRedo().

If none of the stacks are active, or if the group is empty, this function returns false.

See also: canUndo(), setActiveStack()

Definition at line 356 of file qundogroup.cpp.

References d.

Referenced by createRedoAction().

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◆ canRedoChanged

void QUndoGroup::canRedoChanged ( bool canRedo )

signal

This signal is emitted whenever the active stack emits QUndoStack::canRedoChanged() or the active stack changes.

canRedo is the new state, or false if the active stack is 0.

See also: QUndoStack::canRedoChanged(), setActiveStack()

Referenced by createRedoAction(), and setActiveStack().

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◆ canUndo()

bool QUndoGroup::canUndo ( ) const

Returns the value of the active stack's QUndoStack::canUndo().

If none of the stacks are active, or if the group is empty, this function returns false.

See also: canRedo(), setActiveStack()

Definition at line 341 of file qundogroup.cpp.

References d.

Referenced by createUndoAction().

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◆ canUndoChanged

void QUndoGroup::canUndoChanged ( bool canUndo )

signal

This signal is emitted whenever the active stack emits QUndoStack::canUndoChanged() or the active stack changes.

canUndo is the new state, or false if the active stack is 0.

See also: QUndoStack::canUndoChanged(), setActiveStack()

Referenced by createUndoAction(), and setActiveStack().

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◆ cleanChanged

void QUndoGroup::cleanChanged ( bool clean )

signal

This signal is emitted whenever the active stack emits QUndoStack::cleanChanged() or the active stack changes.

clean is the new state, or true if the active stack is 0.

See also: QUndoStack::cleanChanged(), setActiveStack()

Referenced by setActiveStack().

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◆ createRedoAction()

QAction * QUndoGroup::createRedoAction	(	QObject *	parent,
		const QString &	prefix = `QString()`
	)		const

Creates an redo QAction object with parent parent.

Triggering this action will cause a call to QUndoStack::redo() on the active stack. The text of this action will always be the text of the command which will be redone in the next call to redo(), prefixed by prefix. If there is no command available for redo, if the group is empty or if none of the stacks are active, this action will be disabled.

If prefix is empty, the default template "Redo %1" is used instead of prefix. Before Qt 4.8, the prefix "Redo" was used by default.

See also: createUndoAction(), canRedo(), QUndoCommand::text()

Definition at line 275 of file qundogroup.cpp.

References canRedo(), canRedoChanged(), QObject::connect(), QString::isEmpty(), QObject::parent(), redo(), redoText(), redoTextChanged(), QAction::setEnabled(), text, tr, and QAction::triggered().

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◆ createUndoAction()

QAction * QUndoGroup::createUndoAction	(	QObject *	parent,
		const QString &	prefix = `QString()`
	)		const

Creates an undo QAction object with parent parent.

Triggering this action will cause a call to QUndoStack::undo() on the active stack. The text of this action will always be the text of the command which will be undone in the next call to undo(), prefixed by prefix. If there is no command available for undo, if the group is empty or if none of the stacks are active, this action will be disabled.

If prefix is empty, the default template "Undo %1" is used instead of prefix. Before Qt 4.8, the prefix "Undo" was used by default.

See also: createRedoAction(), canUndo(), QUndoCommand::text()

Definition at line 237 of file qundogroup.cpp.

References canUndo(), canUndoChanged(), QObject::connect(), QString::isEmpty(), QObject::parent(), QAction::setEnabled(), text, tr, QAction::triggered(), undo(), undoText(), and undoTextChanged().

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◆ indexChanged

void QUndoGroup::indexChanged ( int idx )

signal

This signal is emitted whenever the active stack emits QUndoStack::indexChanged() or the active stack changes.

idx is the new current index, or 0 if the active stack is 0.

See also: QUndoStack::indexChanged(), setActiveStack()

Referenced by setActiveStack().

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◆ isClean()

bool QUndoGroup::isClean ( ) const

Returns the value of the active stack's QUndoStack::isClean().

If none of the stacks are active, or if the group is empty, this function returns true.

See also: setActiveStack()

Definition at line 401 of file qundogroup.cpp.

References d.

◆ redo

void QUndoGroup::redo ( )

slot

Calls QUndoStack::redo() on the active stack.

If none of the stacks are active, or if the group is empty, this function does nothing.

See also: undo(), canRedo(), setActiveStack()

Definition at line 325 of file qundogroup.cpp.

References d.

Referenced by createRedoAction().

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◆ redoText()

QString QUndoGroup::redoText ( ) const

Returns the value of the active stack's QUndoStack::redoText().

If none of the stacks are active, or if the group is empty, this function returns an empty string.

See also: undoText(), setActiveStack()

Definition at line 386 of file qundogroup.cpp.

References d.

Referenced by createRedoAction().

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◆ redoTextChanged

void QUndoGroup::redoTextChanged ( const QString & redoText )

signal

This signal is emitted whenever the active stack emits QUndoStack::redoTextChanged() or the active stack changes.

redoText is the new state, or an empty string if the active stack is 0.

See also: QUndoStack::redoTextChanged(), setActiveStack()

Referenced by createRedoAction(), and setActiveStack().

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◆ removeStack()

void QUndoGroup::removeStack ( QUndoStack * stack )

Removes stack from this group.

If the stack was the active stack in the group, the active stack becomes 0.

See also: addStack(), stacks(), QUndoStack::~QUndoStack()

Definition at line 114 of file qundogroup.cpp.

References d, and setActiveStack().

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◆ setActiveStack

void QUndoGroup::setActiveStack ( QUndoStack * stack )

slot

Sets the active stack of this group to stack.

If the stack is not a member of this group, this function does nothing.

Synonymous with calling QUndoStack::setActive() on stack.

The actions returned by createUndoAction() and createRedoAction() will now behave in the same way as those returned by stack's QUndoStack::createUndoAction() and QUndoStack::createRedoAction().

See also: QUndoStack::setActive(), activeStack()

Definition at line 151 of file qundogroup.cpp.

References activeStackChanged(), canRedoChanged(), canUndoChanged(), cleanChanged(), QObject::connect(), d, disconnect(), emit, indexChanged(), redoTextChanged(), SIGNAL, and undoTextChanged().

Referenced by removeStack().

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◆ stacks()

QList< QUndoStack * > QUndoGroup::stacks ( ) const

Returns a list of stacks in this group.

See also: addStack(), removeStack()

Definition at line 131 of file qundogroup.cpp.

References d.

◆ undo

void QUndoGroup::undo ( )

slot

Calls QUndoStack::undo() on the active stack.

If none of the stacks are active, or if the group is empty, this function does nothing.

See also: redo(), canUndo(), setActiveStack()

Definition at line 308 of file qundogroup.cpp.

References d.

Referenced by createUndoAction().

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◆ undoText()

QString QUndoGroup::undoText ( ) const

Returns the value of the active stack's QUndoStack::undoText().

If none of the stacks are active, or if the group is empty, this function returns an empty string.

See also: redoText(), setActiveStack()

Definition at line 371 of file qundogroup.cpp.

References d.

Referenced by createUndoAction().

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◆ undoTextChanged

void QUndoGroup::undoTextChanged ( const QString & undoText )

signal

This signal is emitted whenever the active stack emits QUndoStack::undoTextChanged() or the active stack changes.

undoText is the new state, or an empty string if the active stack is 0.

See also: QUndoStack::undoTextChanged(), setActiveStack()

Referenced by createUndoAction(), and setActiveStack().

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

qtbase/src/gui/util/qundogroup.h
qtbase/src/gui/util/qundogroup.cpp

Public Slots

Signals

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QUndoGroup()

◆ ~QUndoGroup()

Member Function Documentation

◆ activeStack()

◆ activeStackChanged

◆ addStack()

◆ canRedo()

◆ canRedoChanged

◆ canUndo()

◆ canUndoChanged

◆ cleanChanged

◆ createRedoAction()

◆ createUndoAction()

◆ indexChanged

◆ isClean()

◆ redo

◆ redoText()

◆ redoTextChanged

◆ removeStack()

◆ setActiveStack

◆ stacks()

◆ undo

◆ undoText()

◆ undoTextChanged