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Wt::WMenu Class Reference

A widget that shows a menu of options. More...

#include <Wt/WMenu>

Inheritance diagram for Wt::WMenu:
Inheritance graph
[legend]

List of all members.

Public Member Functions

 WMenu (Orientation orientation, WContainerWidget *parent=0)
 Creates a new menu.
 WMenu (WStackedWidget *contentsStack, Orientation orientation, WContainerWidget *parent=0)
 Creates a new menu.
 ~WMenu ()
 Destructor.
WMenuItemaddItem (const WString &name, WWidget *contents, WMenuItem::LoadPolicy policy=WMenuItem::LazyLoading)
 Adds an item.
WMenuItemaddItem (WMenuItem *item)
 Adds an item.
void removeItem (WMenuItem *item)
 Removes an item.
void select (WMenuItem *item)
 Selects an item.
void select (int index)
 Selects an item.
Signal< WMenuItem * > & itemSelected ()
 Signal which indicates that a new item was selected.
Signal< WMenuItem * > & itemSelectRendered ()
 Signal which indicates that a new selected item is rendered.
void close (WMenuItem *item)
 Closes an item.
void close (int index)
 Closes an item.
const std::vector< WMenuItem * > & items () const
 Returns the items.
Signal< WMenuItem * > & itemClosed ()
 Signal which indicates that an item was closed.
void setItemHidden (WMenuItem *item, bool hidden)
 Hides an item.
void setItemHidden (int index, bool hidden)
 Hides an item.
bool isItemHidden (WMenuItem *item) const
 Returns whether the item widget of the given item is hidden.
bool isItemHidden (int index) const
 Returns whether the item widget of the given index is hidden.
void setItemDisabled (WMenuItem *item, bool disabled)
 Disables an item.
void setItemDisabled (int index, bool disabled)
 Disables an item.
bool isItemDisabled (WMenuItem *item) const
 Returns whether the item widget of the given item is disabled.
bool isItemDisabled (int index) const
 Returns whether the item widget of the given index is disabled.
WMenuItemcurrentItem () const
 Returns the currently selected item.
int currentIndex () const
 Returns the index of the currently selected item.
Orientation orientation () const
 Returns the orientation.
void setRenderAsList (bool enable)
 Renders using an HTML list.
bool renderAsList () const
 Returns whether the menu is rendered as an HTML list.
void setInternalPathEnabled (const std::string &basePath="")
 Enables internal paths for items.
bool internalPathEnabled () const
 Returns whether the menu generates internal paths entries.
void setInternalBasePath (const std::string &basePath)
 Sets the internal base path.
const std::string & internalBasePath () const
 Returns the internal base path.
WStackedWidgetcontentsStack () const
 Returns the contents stack associated with the menu.
- Public Member Functions inherited from Wt::WCompositeWidget
 WCompositeWidget (WContainerWidget *parent=0)
 Creates a WCompositeWidget.
 WCompositeWidget (WWidget *implementation, WContainerWidget *parent)
 Creates a WCompositeWidget with given implementation.
virtual const std::string id () const
 Returns the (unique) identifier for this object.
virtual void setPositionScheme (PositionScheme scheme)
 Sets the CSS position scheme.
virtual PositionScheme positionScheme () const
 Returns the CSS position scheme.
virtual void setOffsets (const WLength &offset, WFlags< Side > sides=All)
 Sets CSS offsets for a non-statically positioned widget.
virtual WLength offset (Side s) const
 Returns a CSS offset.
virtual void resize (const WLength &width, const WLength &height)
 Resizes the widget.
virtual WLength width () const
 Returns the width.
virtual WLength height () const
 Returns the height.
virtual void setMinimumSize (const WLength &width, const WLength &height)
 Sets a minimum size.
virtual WLength minimumWidth () const
 Returns the minimum width.
virtual WLength minimumHeight () const
 Returns the minimum height.
virtual void setMaximumSize (const WLength &width, const WLength &height)
 Sets a maximum size.
virtual WLength maximumWidth () const
 Returns the maximum width.
virtual WLength maximumHeight () const
 Returns the maximum height.
virtual void setLineHeight (const WLength &height)
 Sets the CSS line height for contained text.
virtual WLength lineHeight () const
 Returns the CSS line height for contained text.
virtual void setFloatSide (Side s)
 Specifies a CSS float side.
virtual Side floatSide () const
 Returns the CSS float side.
virtual void setClearSides (WFlags< Side > sides)
 Sets the sides that should be cleared of floats.
virtual WFlags< SideclearSides () const
 Returns the sides that should remain empty.
virtual void setMargin (const WLength &margin, WFlags< Side > sides=All)
 Sets CSS margins around the widget.
virtual WLength margin (Side side) const
 Returns a CSS margin set.
virtual void setHiddenKeepsGeometry (bool enabled)
 Sets whether the widget keeps its geometry when hidden.
virtual bool hiddenKeepsGeometry () const
 Returns whether the widget keeps its geometry when hidden.
virtual void setHidden (bool hidden, const WAnimation &animation=WAnimation())
 Hides or shows the widget.
virtual bool isHidden () const
 Returns whether the widget is set hidden.
virtual bool isVisible () const
 Returns whether the widget is visible.
virtual void setDisabled (bool disabled)
 Sets whether the widget is disabled.
virtual bool isDisabled () const
 Returns whether the widget is set disabled.
virtual bool isEnabled () const
 Returns whether the widget is enabled.
virtual void setPopup (bool popup)
 Lets the widget overlay over other sibling widgets.
virtual bool isPopup () const
 Returns whether the widget is overlayed.
virtual void setInline (bool isInline)
 Sets whether the widget is displayed inline or as a block.
virtual bool isInline () const
 Returns whether the widget is displayed inline or as block.
virtual void setDecorationStyle (const WCssDecorationStyle &style)
 Sets a CSS decoration style.
virtual WCssDecorationStyledecorationStyle ()
 Returns the decoration style of this widget.
virtual void setStyleClass (const WString &styleClass)
 Sets (one or more) CSS style classes.
virtual WString styleClass () const
 Returns the CSS style class.
virtual void addStyleClass (const WString &styleClass, bool force=false)
 Adds a CSS style class.
virtual void removeStyleClass (const WString &styleClass, bool force=false)
 Removes a CSS style class.
virtual void setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength::Auto)
 Sets the vertical alignment.
virtual AlignmentFlag verticalAlignment () const
 Returns the vertical alignment.
virtual WLength verticalAlignmentLength () const
 Returns the fixed vertical alignment that was set.
virtual void setToolTip (const WString &text, TextFormat textFormat=PlainText)
 Sets a tooltip.
virtual WString toolTip () const
 Returns the tooltip.
virtual void refresh ()
 Refresh the widget.
virtual void setAttributeValue (const std::string &name, const WString &value)
 Sets an attribute value.
virtual WString attributeValue (const std::string &name) const
 Returns an attribute value.
virtual void setJavaScriptMember (const std::string &name, const std::string &value)
 Sets a JavaScript member.
virtual std::string javaScriptMember (const std::string &name) const
 Returns the value of a JavaScript member.
virtual void callJavaScriptMember (const std::string &name, const std::string &args)
 Calls a JavaScript member.
virtual void load ()
 Loads content just before the widget is used.
virtual bool loaded () const
 Returns whether this widget has been loaded.
virtual void setTabIndex (int index)
 Sets the tab index.
virtual int tabIndex () const
 Returns the tab index.
virtual void setId (const std::string &id)
 Sets the CSS Id.
virtual WWidgetfind (const std::string &name)
 Finds a descendent widget by name.
virtual void setSelectable (bool selectable)
 Sets as selectable.
virtual void doJavaScript (const std::string &js)
 Executes the given JavaScript statements when the widget is rendered or updated.
virtual void propagateSetEnabled (bool enabled)
 Propagates that a widget was enabled or disabled through children.
- Public Member Functions inherited from Wt::WWidget
virtual ~WWidget ()
 Destructor.
WWidgetparent () const
 Returns the parent widget.
void setWidth (const WLength &width)
 Sets the width.
void setHeight (const WLength &height)
 Sets the height.
virtual void positionAt (const WWidget *widget, Orientation orientation=Vertical)
 Positions a widget next to another widget.
std::string jsRef () const
 Returns a JavaScript expression to the corresponding DOM node.
virtual void acceptDrops (const std::string &mimeType, const WString &hoverStyleClass=WString())
 Sets a mime type to be accepted for dropping.
virtual void stopAcceptDrops (const std::string &mimeType)
 Indicates that a mime type is no longer accepted for dropping.
virtual void htmlText (std::ostream &out)
 Streams the (X)HTML representation.
bool isRendered () const
 Returns whether the widget is rendered.
void hide ()
 Hides the widget.
void animateHide (const WAnimation &animation)
 Hides the widget using an animation.
void show ()
 Shows the widget.
void animateShow (const WAnimation &animation)
 Shows the widget using an animation.
void enable ()
 Enables the widget.
void disable ()
 Disable thes widget.
bool layoutSizeAware () const
 Returns whether the widget is layout size aware.
- Public Member Functions inherited from Wt::WObject
 WObject (WObject *parent=0)
 Create a WObject with a given parent object.
virtual ~WObject ()
 Destructor.
void setObjectName (const std::string &name)
 Sets an object name.
virtual std::string objectName () const
 Returns the object name.
void resetLearnedSlots ()
 Resets learned stateless slot implementations.
template<class T >
void resetLearnedSlot (void(T::*method)())
 Resets a learned stateless slot implementation.
template<class T >
WStatelessSlot * implementStateless (void(T::*method)())
 Declares a slot to be stateless and learn client-side behaviour on first invocation.
template<class T >
WStatelessSlot * implementStateless (void(T::*method)(), void(T::*undoMethod)())
 Declares a slot to be stateless and learn client-side behaviour in advance.
template<class T >
WStatelessSlot * implementJavaScript (void(T::*method)(), const std::string &jsCode)
 Provides a JavaScript implementation for a method.
void addChild (WObject *child)
 Adds a child object.
virtual void removeChild (WObject *child)
 Removes a child object.
const std::vector< WObject * > & children () const
 Returns the children.

Protected Member Functions

virtual void enableAjax ()
 Progresses to an Ajax-enabled widget.
virtual void internalPathChanged (const std::string &path)
 Handling of internal path changes.
virtual int nextAfterHide (int index)
 Returns the index of the item to be selected after hides.
- Protected Member Functions inherited from Wt::WCompositeWidget
void setImplementation (WWidget *widget)
 Set the implementation widget.
WWidgetimplementation ()
 Get the implementation widget.
virtual int boxPadding (Orientation orientation) const
 Returns the widget's built-in padding.
virtual int boxBorder (Orientation orientation) const
 Returns the widget's built-in border width.
- Protected Member Functions inherited from Wt::WWidget
void setLayoutSizeAware (bool sizeAware)
 Sets the widget to be aware of its size set by a layout manager.
virtual void layoutSizeChanged (int width, int height)
 Virtual method that indicates a size change.
 WWidget (WContainerWidget *parent=0)
 Creates a widget.
virtual void dropEvent (WDropEvent dropEvent)
 Handles a drop event.
virtual WStatelessSlot * getStateless (Method method)
 On-demand stateless slot implementation.

Detailed Description

A widget that shows a menu of options.

The WMenu widget offers menu navigation.

Typically, a menu is used in conjunction with a WStackedWidget (but can be used without too), where different 'contents' are stacked upon each other. Each choice in the menu (which is implemented as a WMenuItem) corresponds to a tab in the contents stack. The contents stack may contain other items, and could be shared with other WMenu instances.

When used without a contents stack, you can react to menu item selection using the itemSelected() signal, to implement some custom handling of item selection.

Usage example:

// create the stack where the contents will be located
Wt::WStackedWidget *contents = new Wt::WStackedWidget(contentsParent);
// create a menu
Wt::WMenu *menu = new Wt::WMenu(contents, Wt::Vertical, menuParent);
menu->setRenderAsList(true);
// add four items using the default lazy loading policy.
menu->addItem("Introduction", new Wt::WText("intro"));
menu->addItem("Download", new Wt::WText("Not yet available"));
menu->addItem("Demo", new DemoWidget());
menu->addItem(new Wt::WMenuItem("Demo2", new DemoWidget()));

Historically, a menu was implemented as a table, but rendering as a list (<ul>) is preferred, as it is the norm form implementations.

After contruction, the first entry will be selected. At any time, it is possible to select a particular item using select().

Each item of WMenu may be closeable (see WMenuItem::setCloseable(bool). Like selection, at any time, it is possible to close a particular item using close(). You can react to close of item by using the itemClosed() signal.

The WMenu implementation offers fine-grained control on how contents should be preloaded. By default, all contents is lazy-loaded, only when needed. To improve response time, an item may also be preloaded (using addItem()). In that case, the item will be loaded in the background, before its first use. In any case, once the contents corresponding to a menu item is loaded, subsequent navigation to it is handled entirely client-side.

The WMenu may participate in the application's internal path, which lets menu items correspond to internal URLs, see setInternalPathEnabled().

The layout of the menu may be Horizontal or Vertical. The look of the items may be defined through style sheets. The default WMenuItem implementation uses four style classes to distinguish between inactivated, activated, closeable inactivated and closeable activated menu items: "item", "itemselected", "citem", "citemselected". By using CSS nested selectors, a different style may be defined for items in a different menu.

You may customize the rendering and behaviour of menu entries by specializing WMenuItem.

CSS

Styling a menu will be different depending of the rendering mode (table, list). Conventionally, menus like this are styled as a list (setRenderAsList()).

You will want to differentiate between unselected and selected items based on the "item" and "itemselected" style classes as well as between unselected and selected closeable items based on the "citem" and "citemselected" style classes.

For menus without closeable items a styling is pretty simple. For example, assuming you set a "menu" style class for your menu, you can style the items using:

.menu * .item {
cursor: pointer; cursor: hand;
color: blue;
text-decoration: underline;
}
.menu * .itemselected {
color: blue;
text-decoration: underline;
font-weight: bold;
}

For menus which supports closing and/or enabling disabling of items, the styling is more complex. The close icon is styled by the current CSS theme and can be overriden by using "Wt-closeicon" CSS class. The look of the menu, assuming the default implementation for WMenuItem, can be customized by using the following selectors (again assuming a menu with as styleclass "menu"):

.Wt-closeicon                     : a close icon

.menu                             : the list (you custom menu class)
.menu li                          : a list item
.menu span                        : spans of a list item

# not closable items:
.menu a.item span                 : the inner span of the label of an enabled item
.menu span.item                   : the label of a disabled item
.menu a.itemselected span         : the inner span the label of an enabled selected item
.menu span.itemselected           : the label of a disabled selected item

# closable items:
.menu .citem a.label span         : the inner span of the label of an enabled item
.menu .citem span.label           : the label of a disabled item
.menu .citemselected a.label span : the inner span the label of an enabled selected item
.menu .citemselected span.label   : the label of a disabled selected item

Example of styling a menu with closeable items:

.menu {
overflow: auto;
}
.menu li {
display: inline;
}
.menu span {
display: block; float: left;
}
.menu a.item span {
cursor: pointer; cursor: hand;
color: blue;
margin-right: 5px;
}
.menu span.item {
color: gray;
margin-right: 5px;
}
.menu a.itemselected span {
color: black;
font-weight: bold;
text-decoration: none;
margin-right: 5px;
}
.menu span.itemselected {
color: gray;
font-weight: bold;
text-decoration: none;
margin-right: 5px;
}
.menu .citem a.label span {
cursor: pointer; cursor: hand;
color: blue;
}
.menu .citem span.label {
color: gray;
}
.menu .citemselected a.label span {
color: black;
font-weight: bold;
text-decoration: none;
}
.menu .citemselected span.label {
color: gray;
font-weight: bold;
text-decoration: none;
}
See also:
WMenuItem

Constructor & Destructor Documentation

Wt::WMenu::WMenu ( Orientation  orientation,
WContainerWidget parent = 0 
)

Creates a new menu.

Construct a menu with given orientation. The menu is not associated with a contents stack, and thus you will want to react to the itemSelected() signal to react to menu changes.

Wt::WMenu::WMenu ( WStackedWidget contentsStack,
Orientation  orientation,
WContainerWidget parent = 0 
)

Creates a new menu.

Construct a menu to manage the widgets in contentsStack, and sets the menu orientation.

Each menu item will manage a single widget in the contentsStack, making it the current widget when the menu item is activated.


Member Function Documentation

WMenuItem * Wt::WMenu::addItem ( const WString name,
WWidget contents,
WMenuItem::LoadPolicy  policy = WMenuItem::LazyLoading 
)

Adds an item.

Adds a menu item with given contents, which is added to the menu's associated contents stack.

contents may be 0 for two reasons:

  • if the menu is not associated with a contents stack, then you cannot associate a menu item with a contents widget
  • or, you may have one or more items which which are not associated with a contents widget in the contents stack.

Returns the corresponding WMenuItem.

See also:
addItem(WMenuItem *)
WMenuItem * Wt::WMenu::addItem ( WMenuItem item)

Adds an item.

Adds a menu item. Use this form to add specialized WMenuItem implementations.

See also:
addItem(const WString&, WWidget *, WMenuItem::LoadPolicy)
void Wt::WMenu::close ( WMenuItem item)

Closes an item.

Close the menu item item. Only closeable items can be closed.

See also:
close(int), WMenuItem::close()
void Wt::WMenu::close ( int  index)

Closes an item.

Menu items in a menu with N items are numbered from 0 to N - 1.

See also:
close(WMenuItem *)
int Wt::WMenu::currentIndex ( ) const

Returns the index of the currently selected item.

See also:
currentItem(), select(int)
WMenuItem * Wt::WMenu::currentItem ( ) const

Returns the currently selected item.

See also:
currentIndex(), select(WMenuItem *)
void Wt::WMenu::enableAjax ( )
protectedvirtual

Progresses to an Ajax-enabled widget.

This method is called when the progressive bootstrap method is used, and support for AJAX has been detected. The default behavior will upgrade the widget's event handling to use AJAX instead of full page reloads, and propagate the call to its children.

You may want to reimplement this method if you want to make changes to widget when AJAX is enabled. You should always call the base implementation.

See also:
WApplication::enableAjax()

Reimplemented from Wt::WCompositeWidget.

const std::string& Wt::WMenu::internalBasePath ( ) const

Returns the internal base path.

The default value is the application's internalPath (WApplication::internalPath()) that was recorded when setInternalPathEnabled() was called, and together with each WMenuItem::pathComponent() determines the paths for each item.

For example, if internalBasePath() is "/examples/" and pathComponent() for a particular item is "charts/", then the internal path for that item will be "/examples/charts/".

See also:
setInternalPathEnabled()
void Wt::WMenu::internalPathChanged ( const std::string &  path)
protectedvirtual

Handling of internal path changes.

This methods makes the menu react to internal path changes (and also the initial internal path).

You may want to reimplement this if you want to customize the internal path handling.

bool Wt::WMenu::internalPathEnabled ( ) const

Returns whether the menu generates internal paths entries.

See also:
setInternalPathEnabled()
bool Wt::WMenu::isItemDisabled ( WMenuItem item) const

Returns whether the item widget of the given item is disabled.

See also:
setItemDisabled()
bool Wt::WMenu::isItemDisabled ( int  index) const

Returns whether the item widget of the given index is disabled.

Menu items in a menu with N items are numbered from 0 to N - 1.

See also:
setItemDisabled()
bool Wt::WMenu::isItemHidden ( WMenuItem item) const

Returns whether the item widget of the given item is hidden.

See also:
setItemHidden()
bool Wt::WMenu::isItemHidden ( int  index) const

Returns whether the item widget of the given index is hidden.

Menu items in a menu with N items are numbered from 0 to N - 1.

See also:
setItemHidden()
Signal<WMenuItem *>& Wt::WMenu::itemClosed ( )

Signal which indicates that an item was closed.

This signal is emitted when an item was closed. It is emitted both when the user closes an item, or when close() was invoked.

const std::vector<WMenuItem *>& Wt::WMenu::items ( ) const

Returns the items.

Returns the list of menu items in this menu.

Signal<WMenuItem *>& Wt::WMenu::itemSelected ( )

Signal which indicates that a new item was selected.

This signal is emitted when an item was selected. It is emitted both when the user activated an item, or when select() was invoked.

See also:
itemSelectRendered()
Signal<WMenuItem *>& Wt::WMenu::itemSelectRendered ( )

Signal which indicates that a new selected item is rendered.

This signal is similar to itemSelected, but is emitted from within a stateless slot. Therefore, any slot connected to this signal will be optimized to client-side JavaScript, and must support the contract of a stateless slot (i.e., be idempotent).

If you are unsure what is the difference with the itemSelected signal, you'll probably need the latter instead.

See also:
itemSelected()
int Wt::WMenu::nextAfterHide ( int  index)
protectedvirtual

Returns the index of the item to be selected after hides.

Returns the index of the item to be selected after the item with given index will be hidden.

By default, if the given index is an index of currently selected item, returns an index of the first visible item to the right of it. If it is not found, returns the index of the first visible item to the left of it. If there are no visible items around the currently selected item, returns the index of currently selected item.

You may want to reimplement this if you want to customize the algorithm of determining the index of the item to be selected after hiding the item with given index.

Orientation Wt::WMenu::orientation ( ) const

Returns the orientation.

The orientation is set at time of construction.

void Wt::WMenu::removeItem ( WMenuItem item)

Removes an item.

Removes the given item. The item and its contents is not deleted.

See also:
addItem()
bool Wt::WMenu::renderAsList ( ) const

Returns whether the menu is rendered as an HTML list.

See also:
setRenderAsList(bool)
void Wt::WMenu::select ( WMenuItem item)

Selects an item.

Select the menu item item.

When item is 0, the current selection is removed.

See also:
select(int), currentItem(), WMenuItem::select()
void Wt::WMenu::select ( int  index)

Selects an item.

Menu items in a menu with N items are numbered from 0 to N - 1.

Using a value of -1 removes the current selection.

See also:
select(WMenuItem *), currentIndex()
void Wt::WMenu::setInternalBasePath ( const std::string &  basePath)

Sets the internal base path.

A '/' is appended to turn it into a folder, if needed.

See also:
setInternalPathEnabled(), internalBasePath()
void Wt::WMenu::setInternalPathEnabled ( const std::string &  basePath = "")

Enables internal paths for items.

The menu participates in the internal path by changing the internal path when an item has been selected, and listening for path changes to react to path selections. As a consequence this allows the user to bookmark the current menu selection and revisit it later, use back/forward buttons to navigate through history of visited menu items, and allows indexing of pages.

For each menu item, WMenuItem::pathComponent() is appended to the basePath, which defaults to the internal path (WApplication::internalPath()). A '/' is appended to the base path, to turn it into a folder, if needed.

By default, menu interaction does not change the application internal path.

See also:
WMenuItem::setPathComponent().
void Wt::WMenu::setItemDisabled ( WMenuItem item,
bool  disabled 
)

Disables an item.

Disables the menu item item. Only an item that is enabled can be selected. By default, all menu items are enabled.

See also:
setItemDisabled(int, bool), WMenuItem::setDisabled()
void Wt::WMenu::setItemDisabled ( int  index,
bool  disabled 
)

Disables an item.

Menu items in a menu with N items are numbered from 0 to N - 1.

See also:
setItemDisabled(WMenuItem *, bool)
void Wt::WMenu::setItemHidden ( WMenuItem item,
bool  hidden 
)

Hides an item.

Hides the menu item item. By default, all menu items are visible.

If the item was currently selected, then the next item to be selected is determined by nextAfterHide().

See also:
setItemHidden(int, bool), WMenuItem::hide()
void Wt::WMenu::setItemHidden ( int  index,
bool  hidden 
)

Hides an item.

Menu items in a menu with N items are numbered from 0 to N - 1.

See also:
setItemHidden(WMenuItem *, bool)
void Wt::WMenu::setRenderAsList ( bool  enable)

Renders using an HTML list.

By default, the the menu is rendered using an HTML <table> element for layout. Setting this option enables rendering using <ul> and <il> elements, as is commonly done for CSS-based designs.

Note:
You cannot use this method after items have been added to the menu.

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