QUndoStack Class Reference

#include <qundostack.h>

Inheritance diagram for QUndoStack:

[legend]Collaboration diagram for QUndoStack:

[legend]List of all members.

---

Detailed Description

The QUndoStack class is a stack of QUndoCommand objects.

Since:

4.2

For an overview of Qt's Undo Framework, see the {Overview of Qt's Undo Framework}{overview document}.

An undo stack maintains a stack of commands that have been applied to a document.

New commands are pushed on the stack using push(). Commands can be undone and redone using undo() and redo(), or by triggering the actions returned by createUndoAction() and createRedoAction().

QUndoStack keeps track of the current command. This is the command which will be executed by the next call to redo(). The index of this command is returned by index(). The state of the edited object can be rolled forward or back using setIndex(). If the top-most command on the stack has already been redone, index() is equal to count().

QUndoStack provides support for undo and redo actions, command compression, command macros, and supports the concept of a {clean state}.

QUndoStack provides convenient undo and redo QAction objects, which can be inserted into a menu or a toolbar. When commands are undone or redone, QUndoStack updates the text properties of these actions to reflect what change they will trigger. The actions are also disabled when no command is available for undo or redo. These actions are returned by QUndoStack::createUndoAction() and QUndoStack::createRedoAction(). @section Command Compression and Macros Command compression is useful when several commands can be compressed into a single command that can be undone and redone in a single operation. For example, when a user types a character in a text editor, a new command is created. This command inserts the character into the document at the cursor position. However, it is more convenient for the user to be able to undo or redo typing of whole words, sentences, or paragraphs. Command compression allows these single-character commands to be merged into a single command which inserts or deletes sections of text. For more information, see QUndoCommand::mergeWith() and push(). A command macro is a sequence of commands, all of which are undone and redone in one go. Command macros are created by giving a command a list of child commands. Undoing or redoing the parent command will cause the child commands to be undone or redone. Command macros may be created explicitly by specifying a parent in the QUndoCommand constructor, or by using the convenience functions beginMacro() and endMacro(). Although command compression and macros appear to have the effect to the user, they often have different uses in an application. Commands that perform small changes to a document may be usefully compressed if there is no need to individually record them, and if only larger changes are relevant to the user. However, for commands that need to be recorded individually, or those that cannot be compressed, it is useful to use macros to provide a more convenient user experience while maintaining a record of each command. @section Clean State QUndoStack supports the concept of a clean state. When the document is saved to disk, the stack can be marked as clean using setClean(). Whenever the stack returns to this state through the use of undo/redo commands, it emits the signal cleanChanged(), which is also emitted when the stack leaves the clean state. This signal is usually used to enable and disable the save actions in the application, and to update the document's title to reflect that it contains unsaved changes. \sa QUndoCommand, QUndoView Definition at line 67 of file qundostack.h.

Public Slots
void	setClean ()
void	setIndex (int idx)
void	undo ()
void	redo ()
void	setActive (bool active=true)
Signals
void	indexChanged (int idx)
void	cleanChanged (bool clean)
void	canUndoChanged (bool canUndo)
void	canRedoChanged (bool canRedo)
void	undoTextChanged (const QString &undoText)
void	redoTextChanged (const QString &redoText)
Public Member Functions
	QUndoStack (QObject *parent=0)
	~QUndoStack ()
void	clear ()
void	push (QUndoCommand *cmd)
bool	canUndo () const
bool	canRedo () const
QString	undoText () const
QString	redoText () const
int	count () const
int	index () const
QString	text (int idx) const
QAction *	createUndoAction (QObject *parent, const QString &prefix=QString()) const
QAction *	createRedoAction (QObject *parent, const QString &prefix=QString()) const
bool	isActive () const
bool	isClean () const
int	cleanIndex () const
void	beginMacro (const QString &text)
void	endMacro ()
Friends
class	QUndoGroup

---

Constructor & Destructor Documentation

QUndoStack::QUndoStack

(

QObject *

parent = 0

)

[explicit]

Constructs an empty undo stack with the parent parent. The stack will initally be in the clean state. If parent is a QUndoGroup object, the stack is automatically added to the group.

See also:

push()

Definition at line 392 of file qundostack.cpp.

References QObject::parent().

    : QObject(*(new QUndoStackPrivate), parent)
{
#ifndef QT_NO_UNDOGROUP
    if (QUndoGroup *group = qobject_cast<QUndoGroup*>(parent))
        group->addStack(this);
#endif
}

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QUndoStack::~QUndoStack

(

)

Destroys the undo stack, deleting any commands that are on it. If the stack is in a QUndoGroup, the stack is automatically removed from the group.

See also:

QUndoStack()

Definition at line 408 of file qundostack.cpp.

References clear(), and d.

{
#ifndef QT_NO_UNDOGROUP
    Q_D(QUndoStack);
    if (d->group != 0)
        d->group->removeStack(this);
#endif
    clear();
}

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---

Member Function Documentation

void QUndoStack::clear

(

)

Clears the command stack by deleting all commands on it, and returns the stack to the clean state.

Commands are not undone or redone; the state of the edited object remains unchanged.

This function is usually used when the contents of the document are abandoned.

See also:

QUndoStack()

Definition at line 431 of file qundostack.cpp.

References d, and qDeleteAll().

Referenced by ~QUndoStack().

{
    Q_D(QUndoStack);

    d->macro_stack.clear();
    qDeleteAll(d->command_list);
    d->command_list.clear();
    d->setIndex(0, true);
}

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void QUndoStack::push

(

QUndoCommand *

cmd

)

Pushes cmd on the stack or merges it with the most recently executed command. In either case, executes cmd by calling its redo() function.

If cmd's id is not -1, and if the id is the same as that of the most recently executed command, QUndoStack will attempt to merge the two commands by calling QUndoCommand::mergeWith() on the most recently executed command. If QUndoCommand::mergeWith() returns true, the cmd is deleted.

In all other cases cmd is simply pushed on the stack.

If the current command index does not point to the top of the stack - ie. if commands were undone before cmd was pushed - the current command and all commands above it are deleted. Hence cmd always ends up being the top-most command on the stack.

Once a command is pushed, the stack takes ownership of it. There are no getters to return the command, since modifying it after it has been executed will almost always lead to corruption of the document's state.

See also:

QUndoCommand::id() QUndoCommand::mergeWith()

Definition at line 465 of file qundostack.cpp.

References canRedo(), canRedoChanged(), canUndo(), canUndoChanged(), QUndoCommandPrivate::child_list, d, QUndoCommand::d, emit, QUndoCommand::id(), indexChanged(), QList< T >::isEmpty(), QList< T >::last(), QUndoCommand::mergeWith(), QUndoCommand::redo(), redoText(), redoTextChanged(), undoText(), and undoTextChanged().

Referenced by qdesigner_internal::SignalSlotEditor::addEmptyConnection(), qdesigner_internal::ContainerWidgetTaskMenu::addPage(), qdesigner_internal::ContainerWidgetTaskMenu::addPageAfter(), QDesignerToolBox::changeOrder(), QDesignerStackedWidget::changeOrder(), QDesignerToolBar::createAction(), QDesignerMenu::createAction(), QDesignerMenuBar::createAction(), QDesignerMenu::deleteAction(), QDesignerMenuBar::deleteMenu(), qdesigner_internal::ConnectionEdit::deleteSelected(), qdesigner_internal::BuddyEditor::deleteSelected(), qdesigner_internal::FormWindow::deleteWidgets(), qdesigner_internal::QDesignerTaskMenu::demoteFromCustomWidget(), QDesignerToolBar::dropEvent(), QDesignerMenu::dropEvent(), QDesignerMenuBar::dropEvent(), qdesigner_internal::FormWindow::dropWidgets(), qdesigner_internal::ActionEditor::editAction(), qdesigner_internal::ConnectionEdit::endConnection(), qdesigner_internal::BuddyEditor::endConnection(), qdesigner_internal::ConnectionEdit::endDrag(), QDesignerMenu::enterEditMode(), QDesignerTabWidget::eventFilter(), qdesigner_internal::TableWidgetEditor::fillTableWidgetFromContents(), qdesigner_internal::TreeWidgetEditor::fillTreeWidgetFromContents(), qdesigner_internal::FormWindow::handleArrowKeyEvent(), qdesigner_internal::FormWindow::insertWidget(), qdesigner_internal::FormWindow::layoutGrid(), qdesigner_internal::FormWindow::layoutGridContainer(), qdesigner_internal::FormWindow::layoutHorizontal(), qdesigner_internal::FormWindow::layoutHorizontalContainer(), qdesigner_internal::FormWindow::layoutHorizontalSplit(), qdesigner_internal::FormWindow::layoutVertical(), qdesigner_internal::FormWindow::layoutVerticalContainer(), qdesigner_internal::FormWindow::layoutVerticalSplit(), QDesignerMenuBar::leaveEditMode(), QDesignerMenu::leaveEditMode(), qdesigner_internal::TabOrderEditor::mousePressEvent(), qdesigner_internal::WidgetHandle::mouseReleaseEvent(), qdesigner_internal::FormWindow::paste(), qdesigner_internal::QDesignerTaskMenu::promoteToCustomWidget(), qdesigner_internal::ContainerWidgetTaskMenu::removeCurrentPage(), qdesigner_internal::FormWindowCursor::resetWidgetProperty(), qdesigner_internal::FormWindow::resizeWidget(), qdesigner_internal::SignalSlotEditor::setSignal(), qdesigner_internal::SignalSlotEditor::setSlot(), qdesigner_internal::ConnectionEdit::setSource(), qdesigner_internal::SignalSlotEditor::setSource(), qdesigner_internal::ConnectionEdit::setTarget(), qdesigner_internal::SignalSlotEditor::setTarget(), qdesigner_internal::FormWindowCursor::setWidgetProperty(), qdesigner_internal::FormWindowManager::slotActionAdjustSizeActivated(), qdesigner_internal::ActionEditor::slotDeleteAction(), QDesignerToolBar::slotInsertSeparator(), qdesigner_internal::ActionEditor::slotNewAction(), QDesignerToolBar::slotNewToolBar(), QDesignerMenuBar::slotRemoveMenuBar(), QDesignerToolBar::slotRemoveSelectedAction(), QDesignerMenu::slotRemoveSelectedAction(), QDesignerMenuBar::slotRemoveSelectedAction(), QDesignerToolBar::slotRemoveToolBar(), QDesignerMenuBar::startDrag(), QDesignerMenu::startDrag(), QDesignerToolBar::startDrag(), QDesignerMenu::swap(), QDesignerMenuBar::swap(), qdesigner_internal::ConnectionEdit::widgetRemoved(), and qdesigner_internal::BuddyEditor::widgetRemoved().

{
    Q_D(QUndoStack);
    cmd->redo();

    bool macro = !d->macro_stack.isEmpty();

    QUndoCommand *cur = 0;
    if (macro) {
        QUndoCommand *macro_cmd = d->macro_stack.last();
        if (!macro_cmd->d->child_list.isEmpty())
            cur = macro_cmd->d->child_list.last();
    } else {
        if (d->index > 0)
            cur = d->command_list.at(d->index - 1);
        while (d->index < d->command_list.size())
            delete d->command_list.takeLast();
        if (d->clean_index > d->index)
            d->clean_index = -1; // we've deleted the clean state
    }

    bool try_merge = cur != 0
                        && cur->id() != -1
                        && cur->id() == cmd->id()
                        && (macro || d->index != d->clean_index);

    if (try_merge && cur->mergeWith(cmd)) {
        delete cmd;
        if (!macro) {
            emit indexChanged(d->index);
            emit canUndoChanged(canUndo());
            emit undoTextChanged(undoText());
            emit canRedoChanged(canRedo());
            emit redoTextChanged(redoText());
        }
    } else {
        if (macro) {
            d->macro_stack.last()->d->child_list.append(cmd);
        } else {
            d->command_list.append(cmd);
            d->setIndex(d->index + 1, false);
        }
    }
}

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bool QUndoStack::canUndo

(

)

const

Returns true if there is a command available for undo; otherwise returns false.

This function returns false if the stack is empty, or if the bottom command on the stack has already been undone.

Synonymous with index() == 0.

See also:

index() canRedo()

Definition at line 682 of file qundostack.cpp.

References d.

Referenced by createUndoAction(), and push().

{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return false;
    return d->index > 0;
}

bool QUndoStack::canRedo

(

)

const

Returns true if there is a command available for redo; otherwise returns false.

This function returns false if the stack is empty or if the top command on the stack has already been redone.

Synonymous with index() == count().

See also:

index() canUndo()

Definition at line 701 of file qundostack.cpp.

References d.

Referenced by createRedoAction(), and push().

{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return false;
    return d->index < d->command_list.size();
}

QString QUndoStack::undoText

(

)

const

Returns the text of the command which will be undone in the next call to undo().

See also:

QUndoCommand::text() redoText()

Definition at line 715 of file qundostack.cpp.

References d.

Referenced by createUndoAction(), and push().

{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return QString();
    if (d->index > 0)
        return d->command_list.at(d->index - 1)->text();
    return QString();
}

QString QUndoStack::redoText

(

)

const

Returns the text of the command which will be redone in the next call to redo().

See also:

QUndoCommand::text() undoText()

Definition at line 731 of file qundostack.cpp.

References d.

Referenced by createRedoAction(), and push().

{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return QString();
    if (d->index < d->command_list.size())
        return d->command_list.at(d->index)->text();
    return QString();
}

int QUndoStack::count

(

)

const

Returns the number of commands on the stack. Macro commands are counted as one command.

See also:

index() setIndex()

Definition at line 621 of file qundostack.cpp.

References d.

Referenced by QUndoModel::data(), QUndoModel::index(), and QUndoModel::rowCount().

{
    Q_D(const QUndoStack);
    return d->command_list.size();
}

int QUndoStack::index

(

)

const

Returns the index of the current command. This is the command that will be executed on the next call to redo(). It is not always the top-most command on the stack, since a number of commands may have been undone.

See also:

undo() redo() count()

Definition at line 635 of file qundostack.cpp.

References d.

Referenced by qdesigner_internal::FormWindow::handleArrowKeyEvent(), QUndoModel::selectedIndex(), qdesigner_internal::FormWindow::setDirty(), and qdesigner_internal::FormWindow::updateDirty().

{
    Q_D(const QUndoStack);
    return d->index;
}

QString QUndoStack::text

(

int

idx

)

const

Returns the text of the command at index idx.

See also:

beginMacro()

Definition at line 896 of file qundostack.cpp.

References d.

Referenced by beginMacro(), and QUndoModel::data().

{
    Q_D(const QUndoStack);

    if (idx < 0 || idx >= d->command_list.size())
        return QString();
    return d->command_list.at(idx)->text();
}

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

Creates an undo QAction object with the given parent.

Triggering this action will cause a call to undo(). The text of this action is the text of the command which will be undone in the next call to undo(), prefixed by the specified prefix. If there is no command available for undo, this action will be disabled.

If prefix is empty, the default prefix "Undo" is used.

See also:

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

Definition at line 756 of file qundostack.cpp.

References canUndo(), canUndoChanged(), QObject::connect(), QString::isEmpty(), QObject::parent(), QAction::setEnabled(), QUndoAction::setPrefixedText(), SIGNAL, SLOT, undo(), undoText(), and undoTextChanged().

{
    QString pref = prefix.isEmpty() ? tr("Undo") : prefix;
    QUndoAction *result = new QUndoAction(pref, parent);
    result->setEnabled(canUndo());
    result->setPrefixedText(undoText());
    connect(this, SIGNAL(canUndoChanged(bool)),
            result, SLOT(setEnabled(bool)));
    connect(this, SIGNAL(undoTextChanged(QString)),
            result, SLOT(setPrefixedText(QString)));
    connect(result, SIGNAL(triggered()), this, SLOT(undo()));
    return result;
}

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

Creates an redo QAction object with the given parent.

Triggering this action will cause a call to redo(). The text of this action is the text of the command which will be redone in the next call to redo(), prefixed by the specified prefix. If there is no command available for redo, this action will be disabled.

If prefix is empty, the default prefix "Redo" is used.

See also:

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

Definition at line 783 of file qundostack.cpp.

References canRedo(), canRedoChanged(), QObject::connect(), QString::isEmpty(), QObject::parent(), redo(), redoText(), redoTextChanged(), QAction::setEnabled(), QUndoAction::setPrefixedText(), SIGNAL, and SLOT.

{
    QString pref = prefix.isEmpty() ? tr("Redo") : prefix;
    QUndoAction *result = new QUndoAction(pref, parent);
    result->setEnabled(canRedo());
    result->setPrefixedText(redoText());
    connect(this, SIGNAL(canRedoChanged(bool)),
            result, SLOT(setEnabled(bool)));
    connect(this, SIGNAL(redoTextChanged(QString)),
            result, SLOT(setPrefixedText(QString)));
    connect(result, SIGNAL(triggered()), this, SLOT(redo()));
    return result;
}

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bool QUndoStack::isActive

(

)

const

Definition at line 938 of file qundostack.cpp.

References d.

{
#ifdef QT_NO_UNDOGROUP
    return true;
#else
    Q_D(const QUndoStack);
    return d->group == 0 || d->group->activeStack() == this;
#endif
}

bool QUndoStack::isClean

(

)

const

If the stack is in the clean state, returns true; otherwise returns false.

See also:

setClean() cleanIndex()

Definition at line 538 of file qundostack.cpp.

References d.

{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return false;
    return d->clean_index == d->index;
}

int QUndoStack::cleanIndex

(

)

const

Returns the clean index. This is the index at which setClean() was called.

A stack may not have a clean index. This happens if a document is saved, some commands are undone, then a new command is pushed. Since push() deletes all the undone commands before pushing the new command, the stack can't return to the clean state again. In this case, this function returns -1.

See also:

isClean() setClean()

Definition at line 557 of file qundostack.cpp.

References d.

Referenced by QUndoModel::data().

{
    Q_D(const QUndoStack);
    return d->clean_index;
}

void QUndoStack::beginMacro

(

const QString &

text

)

Begins composition of a macro command with the given text description.

An empty command described by the specified text is pushed on the stack. Any subsequent commands pushed on the stack will be appended to the empty command's children until endMacro() is called.

Calls to beginMacro() and endMacro() may be nested, but every call to beginMacro() must have a matching call to endMacro().

While a macro is composed, the stack is disabled. This means that: indexChanged() and cleanChanged() are not emitted, canUndo() and canRedo() return false, calling undo() or redo() has no effect, the undo/redo actions are disabled.

The stack becomes enabled and appropriate signals are emitted when endMacro() is called for the outermost macro.

    stack.beginMacro("insert red text");
    stack.push(new InsertText(document, idx, text));
    stack.push(new SetColor(document, idx, text.length(), Qt::red));
    stack.endMacro(); // indexChanged() is emitted

This code is equivalent to:

    QUndoCommand *insertRed = new QUndoCommand(); // an empty command
    insertRed->setText("insert red text");

    new InsertText(document, idx, text, insertRed); // becomes child of insertRed
    new SetColor(document, idx, text.length(), Qt::red, insertRed);

    stack.push(insertRed);

See also:

endMacro()

Definition at line 842 of file qundostack.cpp.

References canRedoChanged(), canUndoChanged(), d, emit, redoTextChanged(), QUndoCommand::setText(), text(), and undoTextChanged().

Referenced by qdesigner_internal::FormWindow::beginCommand(), qdesigner_internal::BuddyEditor::deleteSelected(), qdesigner_internal::BuddyEditor::endConnection(), and qdesigner_internal::BuddyEditor::widgetRemoved().

{
    Q_D(QUndoStack);
    QUndoCommand *cmd = new QUndoCommand();
    cmd->setText(text);

    if (d->macro_stack.isEmpty()) {
        while (d->index < d->command_list.size())
            delete d->command_list.takeLast();
        if (d->clean_index > d->index)
            d->clean_index = -1; // we've deleted the clean state
        d->command_list.append(cmd);
    } else {
        d->macro_stack.last()->d->child_list.append(cmd);
    }
    d->macro_stack.append(cmd);

    if (d->macro_stack.count() == 1) {
        emit canUndoChanged(false);
        emit undoTextChanged(QString());
        emit canRedoChanged(false);
        emit redoTextChanged(QString());
    }
}

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void QUndoStack::endMacro

(

)

Ends composition of a macro command.

If this is the outermost macro in a set nested macros, this function emits indexChanged() once for the entire macro command.

See also:

beginMacro()

Definition at line 876 of file qundostack.cpp.

References d, and qWarning().

Referenced by qdesigner_internal::BuddyEditor::deleteSelected(), qdesigner_internal::FormWindow::endCommand(), qdesigner_internal::BuddyEditor::endConnection(), and qdesigner_internal::BuddyEditor::widgetRemoved().

{
    Q_D(QUndoStack);
    if (d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::endMacro(): no matching beginMacro()");
        return;
    }

    d->macro_stack.removeLast();

    if (d->macro_stack.isEmpty())
        d->setIndex(d->index + 1, false);
}

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void QUndoStack::setClean

(

)

[slot]

Marks the stack as clean and emits cleanChanged() if the stack was not already clean.

Whenever the stack returns to this state through the use of undo/redo commands, it emits the signal cleanChanged(). This signal is also emitted when the stack leaves the clean state.

See also:

isClean(), cleanIndex()

Definition at line 521 of file qundostack.cpp.

References d, and qWarning().

{
    Q_D(QUndoStack);
    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::setClean(): cannot set clean in the middle of a macro");
        return;
    }

    d->setIndex(d->index, true);
}

void QUndoStack::setIndex

(

int

idx

)

[slot]

Repeatedly calls undo() or redo() until the the current command index reaches idx. This function can be used to roll the state of the document forwards of backwards. indexChanged() is emitted only once.

See also:

index() count() undo() redo()

Definition at line 649 of file qundostack.cpp.

References d, i, and qWarning().

Referenced by QUndoModel::setStackCurrentIndex().

{
    Q_D(QUndoStack);
    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::setIndex(): cannot set index in the middle of a macro");
        return;
    }

    if (idx < 0)
        idx = 0;
    else if (idx > d->command_list.size())
        idx = d->command_list.size();

    int i = d->index;
    while (i < idx)
        d->command_list.at(i++)->redo();
    while (i > idx)
        d->command_list.at(--i)->undo();

    d->setIndex(idx, false);
}

void QUndoStack::undo

(

)

[slot]

Undoes the command below the current command by calling QUndoCommand::undo(). Decrements the current command index.

If the stack is empty, or if the bottom command on the stack has already been undone, this function does nothing.

See also:

redo() index()

Definition at line 573 of file qundostack.cpp.

References d, and qWarning().

Referenced by createUndoAction().

{
    Q_D(QUndoStack);
    if (d->index == 0)
        return;

    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::undo(): cannot undo in the middle of a macro");
        return;
    }

    int idx = d->index - 1;
    d->command_list.at(idx)->undo();
    d->setIndex(idx, false);
}

void QUndoStack::redo

(

)

[slot]

Redoes the current command by calling QUndoCommand::redo(). Increments the current command index.

If the stack is empty, or if the top command on the stack has already been redone, this function does nothing.

See also:

undo() index()

Definition at line 599 of file qundostack.cpp.

References d, and qWarning().

Referenced by createRedoAction().

{
    Q_D(QUndoStack);
    if (d->index == d->command_list.size())
        return;

    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::redo(): cannot redo in the middle of a macro");
        return;
    }

    d->command_list.at(d->index)->redo();
    d->setIndex(d->index + 1, false);
}

void QUndoStack::setActive

(

bool

active = true

)

[slot]

Definition at line 922 of file qundostack.cpp.

References d.

Referenced by qdesigner_internal::FormWindowManager::setActiveFormWindow().

{
#ifdef QT_NO_UNDOGROUP
    Q_UNUSED(active);
#else
    Q_D(QUndoStack);

    if (d->group != 0) {
        if (active)
            d->group->setActiveStack(this);
        else if (d->group->activeStack() == this)
            d->group->setActiveStack(0);
    }
#endif
}

void QUndoStack::indexChanged

(

int

idx

)

[signal]

This signal is emitted whenever a command modifies the state of the document. This happens when a command is undone or redone. When a macro command is undone or redone, or setIndex() is called, this signal is emitted only once.

idx specifies the index of the current command, ie. the command which will be executed on the next call to redo().

See also:

index() setIndex()

Referenced by push().

void QUndoStack::cleanChanged

(

bool

clean

)

[signal]

This signal is emitted whenever the stack enters or leaves the clean state. If clean is true, the stack is in a clean state; otherwise this signal indicates that it has left the clean state.

See also:

isClean() setClean()

void QUndoStack::canUndoChanged

(

bool

canUndo

)

[signal]

This signal is emitted whenever the value of canUndo() changes. It is used to enable or disable the undo action returned by createUndoAction(). canUndo specifies the new value.

Referenced by beginMacro(), createUndoAction(), and push().

void QUndoStack::canRedoChanged

(

bool

canUndo

)

[signal]

This signal is emitted whenever the value of canRedo() changes. It is used to enable or disable the redo action returned by createRedoAction(). canUndo specifies the new value.

Referenced by beginMacro(), createRedoAction(), and push().

void QUndoStack::undoTextChanged

(

const QString &

undoText

)

[signal]

This signal is emitted whenever the value of undoText() changes. It is used to update the text property of the undo action returned by createUndoAction(). undoText specifies the new text.

Referenced by beginMacro(), createUndoAction(), and push().

void QUndoStack::redoTextChanged

(

const QString &

redoText

)

[signal]

This signal is emitted whenever the value of redoText() changes. It is used to update the text property of the redo action returned by createRedoAction(). redoText specifies the new text.

Referenced by beginMacro(), createRedoAction(), and push().

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Friends And Related Function Documentation

friend class QUndoGroup [friend]

Definition at line 120 of file qundostack.h.

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

• src/gui/undo/qundostack.h
• src/gui/undo/qundostack.cpp

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