- Qt 5.15
- Qt Widgets
- C++ Classes
- QUndoView
- Qt 5.15.18 Reference Documentation

# QUndoView Class

The QUndoView class displays the contents of a QUndoStack. More...

Header: | #include <QUndoView>
qmake: | QT += widgets
Since: | Qt 4.2
Inherits: | QListView

This class was introduced in Qt 4.2.

- List of all members, including inherited members

## Properties

- cleanIcon : QIcon
- emptyLabel : QString

## Public Functions

| QUndoView(QUndoGroup *group, QWidget *parent = nullptr)
| QUndoView(QUndoStack *stack, QWidget *parent = nullptr)
| QUndoView(QWidget *parent = nullptr)
virtual | ~QUndoView()
QIcon | cleanIcon() const
QString | emptyLabel() const
QUndoGroup * | group() const
void | setCleanIcon(const QIcon &icon)
void | setEmptyLabel(const QString &label)
QUndoStack * | stack() const

## Public Slots

void | setGroup(QUndoGroup *group)
void | setStack(QUndoStack *stack)

## Detailed Description

QUndoView is a QListView which displays the list of commands pushed on an undo stack. The most recently executed command is always selected. Selecting a different command results in a call to QUndoStack::setIndex(), rolling the state of the document backwards or forward to the new command.

The stack can be set explicitly with setStack(). Alternatively, a QUndoGroup object can be set with setGroup(). The view will then update itself automatically whenever the active stack of the group changes.

## Property Documentation

### cleanIcon : QIcon

This property holds the icon used to represent the clean state.

A stack may have a clean state set with QUndoStack::setClean(). This is usually the state of the document at the point it was saved. QUndoView can display an icon in the list of commands to show the clean state. If this property is a null icon, no icon is shown. The default value is the null icon.

Access functions:

QIcon | cleanIcon() const
void | setCleanIcon(const QIcon &icon)

### emptyLabel : QString

This property holds the label used for the empty state.

The empty label is the topmost element in the list of commands, which represents the state of the document before any commands were pushed on the stack. The default is the string "<empty>".

Access functions:

QString | emptyLabel() const
void | setEmptyLabel(const QString &label)

## Member Function Documentation

### QUndoView::QUndoView(QUndoGroup *group, QWidget *parent = nullptr)

Constructs a new view with parent parent and sets the observed group to group.

The view will update itself autmiatically whenever the active stack of the group changes.

### QUndoView::QUndoView(QUndoStack *stack, QWidget *parent = nullptr)

Constructs a new view with parent parent and sets the observed stack to stack.

### QUndoView::QUndoView(QWidget *parent = nullptr)

Constructs a new view with parent parent.

### `[slot]` void QUndoView::setGroup(QUndoGroup *group)

Sets the group displayed by this view to group. If group is `nullptr`, the view will be empty.

The view will update itself automatically whenever the active stack of the group changes.

See also group() and setStack().

### `[slot]` void QUndoView::setStack(QUndoStack *stack)

Sets the stack displayed by this view to stack. If stack is `nullptr`, the view will be empty.

If the view was previously looking at a QUndoGroup, the group is set to `nullptr`.

See also stack() and setGroup().

### `[virtual]` QUndoView::~QUndoView()

Destroys this view.

### QUndoGroup *QUndoView::group() const

Returns the group displayed by this view.

If the view is not looking at group, this function returns `nullptr`.

See also setGroup() and setStack().

### QUndoStack *QUndoView::stack() const

Returns the stack currently displayed by this view. If the view is looking at a QUndoGroup, this the group's active stack.

See also setStack() and setGroup().