QMenu Class Reference

The QMenu class provides a menu widget for use in menu bars, context menus, and other popup menus. More...

 #include <QMenu>

Inherits: QWidget.

Inherited by: Q3PopupMenu.

Properties

  • 58 properties inherited from QWidget
  • 1 property inherited from QObject

Public Functions

QMenu ( QWidget * parent = 0 )
QMenu ( const QString & title, QWidget * parent = 0 )
~QMenu ()
QAction * actionAt ( const QPoint & pt ) const
QRect actionGeometry ( QAction * act ) const
QAction * activeAction () const
QAction * addAction ( const QString & text )
QAction * addAction ( const QIcon & icon, const QString & text )
QAction * addAction ( const QString & text, const QObject * receiver, const char * member, const QKeySequence & shortcut = 0 )
QAction * addAction ( const QIcon & icon, const QString & text, const QObject * receiver, const char * member, const QKeySequence & shortcut = 0 )
void addAction ( QAction * action )
QAction * addMenu ( QMenu * menu )
QMenu * addMenu ( const QString & title )
QMenu * addMenu ( const QIcon & icon, const QString & title )
QAction * addSeparator ()
void clear ()
QAction * defaultAction () const
QAction * exec ()
QAction * exec ( const QPoint & p, QAction * action = 0 )
void hideTearOffMenu ()
QIcon icon () const
QAction * insertMenu ( QAction * before, QMenu * menu )
QAction * insertSeparator ( QAction * before )
bool isEmpty () const
bool isTearOffEnabled () const
bool isTearOffMenuVisible () const
QAction * menuAction () const
void popup ( const QPoint & p, QAction * atAction = 0 )
bool separatorsCollapsible () const
void setActiveAction ( QAction * act )
void setDefaultAction ( QAction * act )
void setIcon ( const QIcon & icon )
void setSeparatorsCollapsible ( bool collapse )
void setTearOffEnabled ( bool )
void setTitle ( const QString & title )
QString title () const

Reimplemented Public Functions

virtual QSize sizeHint () const
  • 221 public functions inherited from QWidget
  • 29 public functions inherited from QObject
  • 13 public functions inherited from QPaintDevice

Signals

void aboutToHide ()
void aboutToShow ()
void hovered ( QAction * action )
void triggered ( QAction * action )

Static Public Members

QAction * exec ( QList<QAction *> actions, const QPoint & pos, QAction * at, QWidget * parent )
QAction * exec ( QList<QAction *> actions, const QPoint & pos, QAction * at = 0 )
  • 4 static public members inherited from QWidget
  • 7 static public members inherited from QObject

Protected Functions

int columnCount () const
void initStyleOption ( QStyleOptionMenuItem * option, const QAction * action ) const

Reimplemented Protected Functions

virtual void actionEvent ( QActionEvent * e )
virtual void changeEvent ( QEvent * e )
virtual void enterEvent ( QEvent * )
virtual bool event ( QEvent * e )
virtual bool focusNextPrevChild ( bool next )
virtual void hideEvent ( QHideEvent * )
virtual void keyPressEvent ( QKeyEvent * e )
virtual void leaveEvent ( QEvent * )
virtual void mouseMoveEvent ( QMouseEvent * e )
virtual void mousePressEvent ( QMouseEvent * e )
virtual void mouseReleaseEvent ( QMouseEvent * e )
virtual void paintEvent ( QPaintEvent * e )
virtual void timerEvent ( QTimerEvent * e )
virtual void wheelEvent ( QWheelEvent * e )
  • 37 protected functions inherited from QWidget
  • 8 protected functions inherited from QObject
  • 1 protected function inherited from QPaintDevice

Additional Inherited Members

  • 19 public slots inherited from QWidget
  • 1 public slot inherited from QObject
  • 1 protected slot inherited from QWidget

Detailed Description

The QMenu class provides a menu widget for use in menu bars, context menus, and other popup menus.

A menu widget is a selection menu. It can be either a pull-down menu in a menu bar or a standalone context menu. Pull-down menus are shown by the menu bar when the user clicks on the respective item or presses the specified shortcut key. Use QMenuBar::addMenu() to insert a menu into a menu bar. Context menus are usually invoked by some special keyboard key or by right-clicking. They can be executed either asynchronously with popup() or synchronously with exec(). Menus can also be invoked in response to button presses; these are just like context menus except for how they are invoked.

Fig. A menu shown in Plastique widget style, Windows XP widget style, and Macintosh widget style.

Actions

A menu consists of a list of action items. Actions are added with the addAction(), addActions() and insertAction() functions. An action is represented vertically and rendered by QStyle. In addition, actions can have a text label, an optional icon drawn on the very left side, and shortcut key sequence such as "Ctrl+X".

The existing actions held by a menu can be found with actions().

There are four kinds of action items: separators, actions that show a submenu, widgets, and actions that perform an action. Separators are inserted with addSeparator(), submenus with addMenu(), and all other items are considered action items.

When inserting action items you usually specify a receiver and a slot. The receiver will be notifed whenever the item is triggered(). In addition, QMenu provides two signals, activated() and highlighted(), which signal the QAction that was triggered from the menu.

You clear a menu with clear() and remove individual action items with removeAction().

A QMenu can also provide a tear-off menu. A tear-off menu is a top-level window that contains a copy of the menu. This makes it possible for the user to "tear off" frequently used menus and position them in a convenient place on the screen. If you want this functionality for a particular menu, insert a tear-off handle with setTearOffEnabled(). When using tear-off menus, bear in mind that the concept isn't typically used on Microsoft Windows so some users may not be familiar with it. Consider using a QToolBar instead.

Widgets can be inserted into menus with the QWidgetAction class. Instances of this class are used to hold widgets, and are inserted into menus with the addAction() overload that takes a QAction.

Conversely, actions can be added to widgets with the addAction(), addActions() and insertAction() functions.

Warning: To make QMenu visible on the screen, exec() or popup() should be used instead of show().

QMenu on Qt for Windows CE

If a menu is integrated into the native menubar on Windows Mobile we do not support the signals: aboutToHide (), aboutToShow () and hovered (). It is not possible to display an icon in a native menu on Windows Mobile.

QMenu on Mac OS X with Qt build against Cocoa

QMenu can be inserted only once in a menu/menubar. Subsequent insertions will have no effect or will result in a disabled menu item.

See the Menus example for an example of how to use QMenuBar and QMenu in your application.

Important inherited functions: addAction(), removeAction(), clear(), addSeparator(), and addMenu().

See also QMenuBar, GUI Design Handbook: Menu, Drop-Down and Pop-Up, Application Example, Menus Example, and Recent Files Example.

Property Documentation

icon : QIcon

This property holds the icon of the menu.

This is equivalent to the QAction::icon property of the menuAction().

By default, if no icon is explicitly set, this property contains a null icon.

Access functions:

QIcon icon () const
void setIcon ( const QIcon & icon )

separatorsCollapsible : bool

This property holds whether consecutive separators should be collapsed.

This property specifies whether consecutive separators in the menu should be visually collapsed to a single one. Separators at the beginning or the end of the menu are also hidden.

By default, this property is true.

This property was introduced in Qt 4.2.

Access functions:

bool separatorsCollapsible () const
void setSeparatorsCollapsible ( bool collapse )

tearOffEnabled : bool

This property holds whether the menu supports being torn off.

When true, the menu contains a special tear-off item (often shown as a dashed line at the top of the menu) that creates a copy of the menu when it is triggered.

This "torn-off" copy lives in a separate window. It contains the same menu items as the original menu, with the exception of the tear-off handle.

By default, this property is false.

Access functions:

bool isTearOffEnabled () const
void setTearOffEnabled ( bool )

title : QString

This property holds the title of the menu.

This is equivalent to the QAction::text property of the menuAction().

By default, this property contains an empty string.

Access functions:

QString title () const
void setTitle ( const QString & title )

Member Function Documentation

QMenu::QMenu ( QWidget * parent = 0 )

Constructs a menu with parent parent.

Although a popup menu is always a top-level widget, if a parent is passed the popup menu will be deleted when that parent is destroyed (as with any other QObject).

QMenu::QMenu ( const QString & title, QWidget * parent = 0 )

Constructs a menu with a title and a parent.

Although a popup menu is always a top-level widget, if a parent is passed the popup menu will be deleted when that parent is destroyed (as with any other QObject).

See also title.

QMenu::~QMenu ()

Destroys the menu.

void QMenu::aboutToHide () [signal]

This signal is emitted just before the menu is hidden from the user.

This function was introduced in Qt 4.2.

See also aboutToShow() and hide().

void QMenu::aboutToShow () [signal]

This signal is emitted just before the menu is shown to the user.

See also aboutToHide() and show().

QAction * QMenu::actionAt ( const QPoint & pt ) const

Returns the item at pt; returns 0 if there is no item there.

void QMenu::actionEvent ( QActionEvent * e ) [virtual protected]

Reimplemented from QWidget::actionEvent().

QRect QMenu::actionGeometry ( QAction * act ) const

Returns the geometry of action act.

QAction * QMenu::activeAction () const

Returns the currently highlighted action, or 0 if no action is currently highlighted.

See also setActiveAction().

QAction * QMenu::addAction ( const QString & text )

This is an overloaded function.

This convenience function creates a new action with text. The function adds the newly created action to the menu's list of actions, and returns it.

See also QWidget::addAction().

QAction * QMenu::addAction ( const QIcon & icon, const QString & text )

This is an overloaded function.

This convenience function creates a new action with an icon and some text. The function adds the newly created action to the menu's list of actions, and returns it.

See also QWidget::addAction().

QAction * QMenu::addAction ( const QString & text, const QObject * receiver, const char * member, const QKeySequence & shortcut = 0 )

This is an overloaded function.

This convenience function creates a new action with the text text and an optional shortcut shortcut. The action's triggered() signal is connected to the receiver's member slot. The function adds the newly created action to the menu's list of actions and returns it.

See also QWidget::addAction().

QAction * QMenu::addAction ( const QIcon & icon, const QString & text, const QObject * receiver, const char * member, const QKeySequence & shortcut = 0 )

This is an overloaded function.

This convenience function creates a new action with an icon and some text and an optional shortcut shortcut. The action's triggered() signal is connected to the member slot of the receiver object. The function adds the newly created action to the menu's list of actions, and returns it.

See also QWidget::addAction().

void QMenu::addAction ( QAction * action )

This is an overloaded function.

Appends the action action to the menu's list of actions.

See also QMenuBar::addAction() and QWidget::addAction().

QAction * QMenu::addMenu ( QMenu * menu )

This convenience function adds menu as a submenu to this menu. It returns menu's menuAction(). This menu does not take ownership of menu.

See also QWidget::addAction() and QMenu::menuAction().

QMenu * QMenu::addMenu ( const QString & title )

Appends a new QMenu with title to the menu. The menu takes ownership of the menu. Returns the new menu.

See also QWidget::addAction() and QMenu::menuAction().

QMenu * QMenu::addMenu ( const QIcon & icon, const QString & title )

Appends a new QMenu with icon and title to the menu. The menu takes ownership of the menu. Returns the new menu.

See also QWidget::addAction() and QMenu::menuAction().

QAction * QMenu::addSeparator ()

This convenience function creates a new separator action, i.e. an action with QAction::isSeparator() returning true, and adds the new action to this menu's list of actions. It returns the newly created action.

See also QWidget::addAction().

void QMenu::changeEvent ( QEvent * e ) [virtual protected]

Reimplemented from QWidget::changeEvent().

void QMenu::clear ()

Removes all the menu's actions. Actions owned by the menu and not shown in any other widget are deleted.

See also removeAction().

int QMenu::columnCount () const [protected]

If a menu does not fit on the screen it lays itself out so that it does fit. It is style dependent what layout means (for example, on Windows it will use multiple columns).

This functions returns the number of columns necessary.

QAction * QMenu::defaultAction () const

Returns the current default action.

See also setDefaultAction().

void QMenu::enterEvent ( QEvent * ) [virtual protected]

Reimplemented from QWidget::enterEvent().

bool QMenu::event ( QEvent * e ) [virtual protected]

Reimplemented from QObject::event().

QAction * QMenu::exec ()

Executes this menu synchronously.

This is equivalent to exec(pos()).

This returns the triggered QAction in either the popup menu or one of its submenus, or 0 if no item was triggered (normally because the user pressed Esc).

In most situations you'll want to specify the position yourself, for example, the current mouse position:

 exec(QCursor::pos());

or aligned to a widget:

 exec(somewidget.mapToGlobal(QPoint(0,0)));

or in reaction to a QMouseEvent *e:

 exec(e->globalPos());

QAction * QMenu::exec ( const QPoint & p, QAction * action = 0 )

This is an overloaded function.

Executes this menu synchronously.

Pops up the menu so that the action action will be at the specified global position p. To translate a widget's local coordinates into global coordinates, use QWidget::mapToGlobal().

This returns the triggered QAction in either the popup menu or one of its submenus, or 0 if no item was triggered (normally because the user pressed Esc).

Note that all signals are emitted as usual. If you connect a QAction to a slot and call the menu's exec(), you get the result both via the signal-slot connection and in the return value of exec().

Common usage is to position the menu at the current mouse position:

 exec(QCursor::pos());

or aligned to a widget:

 exec(somewidget.mapToGlobal(QPoint(0, 0)));

or in reaction to a QMouseEvent *e:

 exec(e->globalPos());

When positioning a menu with exec() or popup(), bear in mind that you cannot rely on the menu's current size(). For performance reasons, the menu adapts its size only when necessary. So in many cases, the size before and after the show is different. Instead, use sizeHint() which calculates the proper size depending on the menu's current contents.

See also popup() and QWidget::mapToGlobal().

QAction * QMenu::exec ( QList<QAction *> actions, const QPoint & pos, QAction * at, QWidget * parent ) [static]

This is an overloaded function.

Executes a menu synchronously.

The menu's actions are specified by the list of actions. The menu will pop up so that the specified action, at, appears at global position pos. If at is not specified then the menu appears at position pos. parent is the menu's parent widget; specifying the parent will provide context when pos alone is not enough to decide where the menu should go (e.g., with multiple desktops or when the parent is embedded in QGraphicsView).

The function returns the triggered QAction in either the popup menu or one of its submenus, or 0 if no item was triggered (normally because the user pressed Esc).

This is equivalent to:

 QMenu menu;
 QAction *at = actions[0]; // Assumes actions is not empty
 foreach (QAction *a, actions)
     menu.addAction(a);
 menu.exec(pos, at);

See also popup() and QWidget::mapToGlobal().

QAction * QMenu::exec ( QList<QAction *> actions, const QPoint & pos, QAction * at = 0 ) [static]

This is an overloaded function.

Executes a menu synchronously.

The menu's actions are specified by the list of actions. The menu will pop up so that the specified action, at, appears at global position pos. If at is not specified then the menu appears at position pos.

The function returns the triggered QAction in either the popup menu or one of its submenus, or 0 if no item was triggered (normally because the user pressed Esc).

This is equivalent to:

 QMenu menu;
 QAction *at = actions[0]; // Assumes actions is not empty
 foreach (QAction *a, actions)
     menu.addAction(a);
 menu.exec(pos, at);

See also popup() and QWidget::mapToGlobal().

bool QMenu::focusNextPrevChild ( bool next ) [virtual protected]

Reimplemented from QWidget::focusNextPrevChild().

void QMenu::hideEvent ( QHideEvent * ) [virtual protected]

Reimplemented from QWidget::hideEvent().

void QMenu::hideTearOffMenu ()

This function will forcibly hide the torn off menu making it disappear from the users desktop.

See also isTearOffMenuVisible() and isTearOffEnabled().

void QMenu::hovered ( QAction * action ) [signal]

This signal is emitted when a menu action is highlighted; action is the action that caused the signal to be emitted.

Often this is used to update status information.

See also triggered() and QAction::hovered().

void QMenu::initStyleOption ( QStyleOptionMenuItem * option, const QAction * action ) const [protected]

Initialize option with the values from this menu and information from action. This method is useful for subclasses when they need a QStyleOptionMenuItem, but don't want to fill in all the information themselves.

See also QStyleOption::initFrom() and QMenuBar::initStyleOption().

QAction * QMenu::insertMenu ( QAction * before, QMenu * menu )

This convenience function inserts menu before action before and returns the menus menuAction().

See also QWidget::insertAction() and addMenu().

QAction * QMenu::insertSeparator ( QAction * before )

This convenience function creates a new separator action, i.e. an action with QAction::isSeparator() returning true. The function inserts the newly created action into this menu's list of actions before action before and returns it.

See also QWidget::insertAction() and addSeparator().

bool QMenu::isEmpty () const

Returns true if there are no visible actions inserted into the menu, false otherwise.

This function was introduced in Qt 4.2.

See also QWidget::actions().

bool QMenu::isTearOffMenuVisible () const

When a menu is torn off a second menu is shown to display the menu contents in a new window. When the menu is in this mode and the menu is visible returns true; otherwise false.

See also hideTearOffMenu() and isTearOffEnabled().

void QMenu::keyPressEvent ( QKeyEvent * e ) [virtual protected]

Reimplemented from QWidget::keyPressEvent().

void QMenu::leaveEvent ( QEvent * ) [virtual protected]

Reimplemented from QWidget::leaveEvent().

QAction * QMenu::menuAction () const

Returns the action associated with this menu.

void QMenu::mouseMoveEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseMoveEvent().

void QMenu::mousePressEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mousePressEvent().

void QMenu::mouseReleaseEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseReleaseEvent().

void QMenu::paintEvent ( QPaintEvent * e ) [virtual protected]

Reimplemented from QWidget::paintEvent().

void QMenu::popup ( const QPoint & p, QAction * atAction = 0 )

Displays the menu so that the action atAction will be at the specified global position p. To translate a widget's local coordinates into global coordinates, use QWidget::mapToGlobal().

When positioning a menu with exec() or popup(), bear in mind that you cannot rely on the menu's current size(). For performance reasons, the menu adapts its size only when necessary, so in many cases, the size before and after the show is different. Instead, use sizeHint() which calculates the proper size depending on the menu's current contents.

See also QWidget::mapToGlobal() and exec().

void QMenu::setActiveAction ( QAction * act )

Sets the currently highlighted action to act.

See also activeAction().

void QMenu::setDefaultAction ( QAction * act )

This sets the default action to act. The default action may have a visual cue, depending on the current QStyle. A default action usually indicates what will happen by default when a drop occurs.

See also defaultAction().

QSize QMenu::sizeHint () const [virtual]

Reimplemented from QWidget::sizeHint().

void QMenu::timerEvent ( QTimerEvent * e ) [virtual protected]

Reimplemented from QObject::timerEvent().

void QMenu::triggered ( QAction * action ) [signal]

This signal is emitted when an action in this menu is triggered.

action is the action that caused the signal to be emitted.

Normally, you connect each menu action's triggered() signal to its own custom slot, but sometimes you will want to connect several actions to a single slot, for example, when you have a group of closely related actions, such as "left justify", "center", "right justify".

Note: This signal is emitted for the main parent menu in a hierarchy. Hence, only the parent menu needs to be connected to a slot; sub-menus need not be connected.

See also hovered() and QAction::triggered().

void QMenu::wheelEvent ( QWheelEvent * e ) [virtual protected]

Reimplemented from QWidget::wheelEvent().

Notes provided by the Qt Community

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