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QMenuBar Class Reference

The QMenuBar class provides a horizontal menu bar. More...

#include <qmenubar.h>

Inherits QFrame and QMenuData.

Inherited by QPEMenuBar.

List of all member functions.

Public Members

Signals

Important Inherited Members

Properties

Protected Members

Detailed Description

The QMenuBar class provides a horizontal menu bar.

A menu bar consists of a list of submenu items, so-called pulldown menus. You add submenu items with insertItem(). Assuming that menubar is a pointer to a QMenuBar and filemenu a pointer to a QPopupMenu, 

  menubar->insertItem( "&File", filemenu );
inserts the menu into the menu bar. The ampersand in the item text declares Alt-f as shortcut for this menu. Use "&&" to get a real ampsend in the menubar.

Items are either enabled or disabled. You toggle their state with setItemEnabled().

Note that there is no need to layout a menu bar. It automatically sets its own geometry to the top of the parent widget and changes it appropriately whenever the parent is resized.

menu/menu.cpp is a typical example of QMenuBar and QPopupMenu use.

See also QPopupMenu and GUI Design Handbook: Menu Bar.

Member Type Documentation

QMenuBar::Separator

This enum type is used to decide whether QMenuBar should draw a separator line at its bottom. The possible values are:

Member Function Documentation

QMenuBar::QMenuBar ( QWidget * parent = 0, const char * name = 0 )

Constructs a menu bar with a parent and a name.

QMenuBar::~QMenuBar ()

Destroys the menu bar.

void QMenuBar::activated ( int id ) [signal]

This signal is emitted when a menu item is selected; id is the id of the selected item.

Normally, you will connect each menu item to a single slot using QMenuData::insertItem(), but sometimes you will want to connect several items to a single slot (most often if the user selects from an array). This signal is handy in such cases.

See also highlighted() and QMenuData::insertItem().

void QMenuData::clear ()

Removes all menu items.

See also removeItem() and removeItemAt().

void QMenuBar::drawContents ( QPainter * p ) [virtual protected]

Called from QFrame::paintEvent().

Reimplemented from QFrame.

int QMenuBar::heightForWidth ( int max_width ) const [virtual]

Returns the height that the menu would resize itself to if its parent (and hence itself) resized to the given width. This can be useful for simple layout tasks where the height of the menubar is needed after items have been inserted. See examples/showimg/showimg.cpp for an example of the usage.

Reimplemented from QWidget.

void QMenuBar::hide () [virtual]

Reimplements QWidget::hide() in order to deselect any selected item and calls setUpLayout() for the mainwindow.

Reimplemented from QWidget.

void QMenuBar::highlighted ( int id ) [signal]

This signal is emitted when a menu item is highlighted; id is the id of the highlighted item.

Normally, you will connect each menu item to a single slot using QMenuData::insertItem(), but sometimes you will want to connect several items to a single slot (most often if the user selects from an array). This signal is handy in such cases.

See also activated() and QMenuData::insertItem().

int QMenuData::insertItem ( const QString & text, const QObject * receiver, const char * member, int accel = 0, int id = -1, int index = -1 )

The family of insertItem() functions inserts menu items into a popup menu or a menu bar.

A menu item is usually either a text string or a a pixmap, both with an optional icon or keyboard accelerator. As special cases it is also possible to insert custom items (see QCustomMenuItem) or even widgets into popup menus.

Some insertItem() members take a popup menu as additional argument. Use these to insert submenus to existing menus or pulldown menus to a menu bar.

The amount of insert functions may look confusing, but is actually quite handy to use.

This default version inserts a menu item with a text, an accelerator key, an id and an optional index and connects it to an object/slot.

Example: 

    QMenuBar   *mainMenu = new QMenuBar;
    QPopupMenu *fileMenu = new QPopupMenu;
    fileMenu->insertItem( "New",  myView, SLOT(newFile()), CTRL+Key_N );
    fileMenu->insertItem( "Open", myView, SLOT(open()),    CTRL+Key_O );
    mainMenu->insertItem( "File", fileMenu );

Not all insert functions take an object/slot parameter or an accelerator key. Use connectItem() and setAccel() on these items.

If you will need to translate accelerators, use QAccel::stringToKey() to calculate the accelerator key: 

    fileMenu->insertItem( tr("Open"), myView, SLOT(open()),
                          QAccel::stringToKey( tr("Ctrl+O") ) );

In the example above, pressing CTRL+N or selecting "open" from the menu activates the myView->open() function.

Some insert functions take a QIconSet parameter to specify the little menu item icon. Note that you can always pass a QPixmap object instead.

The menu item is assigned the identifier id or an automatically generated identifier if id is < 0. The generated identifiers (negative integers) are guaranteed to be unique within the entire application.

The index specifies the position in the menu. The menu item is appended at the end of the list if index is negative.

Note that keyboard accelerators in Qt are not application global, but bound to a certain toplevel window. Accelerators in QPopupMenu items therefore only work for menus that are associated with a certain window. This is true for popup menus that live in a menu bar, for instance. In that case, the accelerator will be installed on the menu bar itself. It also works for stand-alone popup menus that have a toplevel widget in their parentWidget()- chain. The menu will then install its accelerator object on that toplevel widget. For all other cases, use an independent QAccel object.

Warning: Be careful when passing a literal 0 to insertItem(), as some C++ compilers choose the wrong overloaded function. Cast the 0 to what you mean, eg. (QObject*)0.

See also removeItem(), changeItem(), setAccel(), connectItem(), QAccel, and qnamespace.h.

int QMenuData::insertItem ( const QIconSet & icon, const QString & text, const QObject * receiver, const char * member, int accel = 0, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with an icon, a text, an accelerator key, an id and an optional index and connects it to an object/slot. The icon will be displayed to the left of the text in the item.

See also removeItem(), changeItem(), setAccel(), connectItem(), QAccel, and qnamespace.h.

int QMenuData::insertItem ( const QPixmap & pixmap, const QObject * receiver, const char * member, int accel = 0, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with a pixmap, an accelerator key, an id and an optional index and connects it to an object/slot.

To look best when being highlighted as menu item, the pixmap should provide a mask, see QPixmap::mask().

Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QIconSet & icon, const QPixmap & pixmap, const QObject * receiver, const char * member, int accel = 0, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with an icon, a pixmap, an accelerator key, an id and an optional index and connects it to an object/slot. The icon will be displayed to the left of the pixmap in the item.

To look best when being highlighted as menu item, the pixmap should provide a mask, see QPixmap::mask().

Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), connectItem(), QAccel, and qnamespace.h.

int QMenuData::insertItem ( const QString & text, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with a text. Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QIconSet & icon, const QString & text, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with an icon and a text. The icon will be displayed to the left of the text in the item. Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QString & text, QPopupMenu * popup, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with a text and a sub menu.

The popup must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.

Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QIconSet & icon, const QString & text, QPopupMenu * popup, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with an icon, a text and a sub menu. The icon will be displayed to the left of the text in the item.

The popup must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.

Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QPixmap & pixmap, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with a pixmap. Returns the menu item identifier.

To look best when being highlighted as menu item, the pixmap should provide a mask, see QPixmap::mask().

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QIconSet & icon, const QPixmap & pixmap, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with an icon and a pixmap. The icon will be displayed to the left of the pixmap in the item. Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QPixmap & pixmap, QPopupMenu * popup, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with a pixmap and a sub menu. The icon will be displayed to the left of the pixmap in the item.

The popup must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.

Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( const QIconSet & icon, const QPixmap & pixmap, QPopupMenu * popup, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item with an icon, a pixmap and a sub menu. The icon will be displayed to the left of the pixmap in the item.

The popup must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.

Returns the menu item identifier.

See also removeItem(), changeItem(), setAccel(), and connectItem().

int QMenuData::insertItem ( QWidget * widget, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a menu item that consists of the widget widget.

Ownership of widget is transferred to the popup menu or the menubar.

Theoretically, any widget can be inserted into a popup menu. In practice, this only makes sense with certain widgets.

If a widget is not focus enabled ( see QWidget::isFocusEnabled() ), the menu treats it as a separator. This means, the item is not selectable and will never get focus. This way you can for example simply insert a QLabel if you need a popup menu with a title.

If the widget is focus enabled, it will get focus when the user traverses the popup menu with the arrow keys. If the widget does not accept ArrowUp and ArrowDown in its key event handler, the focus will move back to the menu when the the respective arrow key is hit one more time. This works for example with a QLineEdit. If the widget accepts the arrow keys itself, it must also provide the possibility to put the focus back on the menu again by calling QWidget::focusNextPrevChild() respectively. Futhermore should the embedded widget close the menu when the user made a selection. This can be done safely by calling 

 if ( isVisible() &&
  parentWidget() &&
  parentWidget()->inherits("QPopupMenu") )
        parentWidget()->close();

See also removeItem().

int QMenuData::insertItem ( const QIconSet & icon, QCustomMenuItem * custom, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a custom menu item custom with an icon.

This only works with popup menus. It is not supported for menu bars. Ownership of custom is transferred to the popup menu.

If you want to connect a custom item to a certain slot, use connectItem().

See also connectItem(), removeItem(), and QCustomMenuItem.

int QMenuData::insertItem ( QCustomMenuItem * custom, int id = -1, int index = -1 )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Inserts a custom menu item custom.

This only works with popup menus. It is not supported for menu bars. Ownership of custom is transferred to the popup menu.

If you want to connect a custom item to a certain slot, use connectItem().

See also connectItem(), removeItem(), and QCustomMenuItem.

int QMenuData::insertSeparator ( int index = -1 )

Inserts a separator at position index. The separator becomes the last menu item if index is negative.

In a popup menu, a separator is rendered as a horizontal line. In a Motif menubar, a separator is spacing, so the rest of the items (just "Help", normally) are drawn right-justified. In a Windows menubar, separators are ignored (to comply with the Windows style guide).

bool QMenuBar::isDefaultUp () const

Returns whether the menus default to popping "down" the screen (the default), or "up".

See also setDefaultUp().

bool QMenuData::isItemEnabled ( int id ) const

Returns TRUE if the item with identifier id is enabled or FALSE if it is disabled.

See also setItemEnabled().

void QMenuBar::menuContentsChanged () [virtual protected]

Recomputes the menu bar's display data according to the new contents.

You should never need to call this, it is called automatically by QMenuData whenever it needs to be called.

Reimplemented from QMenuData.

void QMenuBar::menuStateChanged () [virtual protected]

Recomputes the menu bar's display data according to the new state.

You should never need to call this, it is called automatically by QMenuData whenever it needs to be called.

Reimplemented from QMenuData.

void QMenuData::removeItem ( int id )

Removes the menu item which has the identifier id.

See also removeItemAt() and clear().

Separator QMenuBar::separator () const

Returns the currently set Separator usage.

See also Separator and setSeparator().

void QMenuBar::setDefaultUp ( bool on )

Sets the default popup orientation. By default, menus pop "down" the screen. By calling setDefaultUp(TRUE) the menu will pop "up". You might call this for menus that are below the document to which they refer.

If the menu would not fit on the screen, the other direction is used rather than the default.

See also defaultUp().

void QMenuData::setItemEnabled ( int id, bool enable )

Enables the menu item with identifier id if enable is TRUE, or disables the item if enable is FALSE.

See also isItemEnabled().

void QMenuBar::setSeparator ( Separator when ) [virtual]

When a menubar is used above an unframed widget, it may look better with a separating line when displayed with WindowsStyle.

This function sets the usage of such a separator to appear either QMenuBar::Never, or QMenuBar::InWindowsStyle.

The default is QMenuBar::Never.

See also Separator and separator().

void QMenuBar::show () [virtual]

Reimplements QWidget::show() in order to set up the correct keyboard accelerators and raise itself to the top of the widget stack.

Reimplemented from QWidget.

This file is part of the Qtopia platform, copyright © 1995-2005 Trolltech, all rights reserved.

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Qtopia version 2.2.0