eu.webtoolkit.jwt
Class WMenu

java.lang.Object
  eu.webtoolkit.jwt.WObject
      eu.webtoolkit.jwt.WWidget
          eu.webtoolkit.jwt.WCompositeWidget
              eu.webtoolkit.jwt.WMenu

public class WMenu
extends WCompositeWidget

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:

 {
        @code
        // create the stack where the contents will be located
        WStackedWidget contents = new WStackedWidget(contentsParent);
 
        // create a menu
        WMenu menu = new WMenu(contents, Orientation.Vertical, menuParent);
        menu.setRenderAsList(true);
 
        // add four items using the default lazy loading policy.
        menu.addItem("Introduction", new WText("intro"));
        menu.addItem("Download", new WText("Not yet available"));
        menu.addItem("Demo", new DemoWidget());
        menu.addItem(new 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(). 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 Summary

WMenu(Orientation orientation)
Creates a new menu.

WMenu(Orientation orientation, WContainerWidget parent)
Creates a new menu.

WMenu(WStackedWidget contentsStack, Orientation orientation)
Creates a new menu.

WMenu(WStackedWidget contentsStack, Orientation orientation, WContainerWidget parent)
Creates a new menu.

Method Summary

WMenuItem	addItem(java.lang.CharSequence name, WWidget contents) Adds an item.
WMenuItem	addItem(java.lang.CharSequence name, WWidget contents, WMenuItem.LoadPolicy policy) Adds an item.
WMenuItem	addItem(WMenuItem item) Adds an item.
void	close(int index) Closes an item.
void	close(WMenuItem item) Closes an item.
protected void	enableAjax() Progresses to an Ajax-enabled widget.
WStackedWidget	getContentsStack() Returns the contents stack associated with the menu.
int	getCurrentIndex() Returns the index of the currently selected item.
WMenuItem	getCurrentItem() Returns the currently selected item.
java.lang.String	getInternalBasePath() Returns the internal base path.
java.util.List<WMenuItem>	getItems() Returns the items.
Orientation	getOrientation() Returns the orientation.
boolean	isInternalPathEnabled() Returns whether the menu generates internal paths entries.
boolean	isItemDisabled(int index) Returns whether the item widget of the given index is disabled.
boolean	isItemDisabled(WMenuItem item) Returns whether the item widget of the given item is disabled.
boolean	isItemHidden(int index) Returns whether the item widget of the given index is hidden.
boolean	isItemHidden(WMenuItem item) Returns whether the item widget of the given item is hidden.
Signal1<WMenuItem>	itemClosed() Signal which indicates that an item was closed.
Signal1<WMenuItem>	itemSelected() Signal which indicates that a new item was selected.
Signal1<WMenuItem>	itemSelectRendered() Signal which indicates that a new selected item is rendered.
protected int	nextAfterHide(int index) Returns the index of the item to be selected after hides.
void	remove() Destructor.
void	removeItem(WMenuItem item) Removes an item.
boolean	renderAsList() Returns whether the menu is rendered as an HTML list.
void	select(int index) Selects an item.
void	select(WMenuItem item) Selects an item.
void	setInternalBasePath(java.lang.String basePath) Sets the internal base path.
void	setInternalPathEnabled() Enables internal paths for items.
void	setInternalPathEnabled(java.lang.String basePath) Enables internal paths for items.
void	setItemDisabled(int index, boolean disabled) Disables an item.
void	setItemDisabled(WMenuItem item, boolean disabled) Disables an item.
void	setItemHidden(int index, boolean hidden) Hides an item.
void	setItemHidden(WMenuItem item, boolean hidden) Hides an item.
void	setRenderAsList(boolean enable) Renders using an HTML list.

Methods inherited from class eu.webtoolkit.jwt.WCompositeWidget

addStyleClass, boxBorder, boxPadding, callJavaScriptMember, doJavaScript, find, getAttributeValue, getClearSides, getDecorationStyle, getFloatSide, getHeight, getId, getImplementation, getJavaScriptMember, getLineHeight, getMargin, getMaximumHeight, getMaximumWidth, getMinimumHeight, getMinimumWidth, getOffset, getPositionScheme, getStyleClass, getTabIndex, getToolTip, getVerticalAlignment, getVerticalAlignmentLength, getWidth, isDisabled, isEnabled, isHidden, isHiddenKeepsGeometry, isInline, isLoaded, isPopup, isVisible, load, propagateSetEnabled, refresh, removeStyleClass, resize, setAttributeValue, setClearSides, setDecorationStyle, setDisabled, setFloatSide, setHidden, setHiddenKeepsGeometry, setId, setImplementation, setInline, setJavaScriptMember, setLineHeight, setMargin, setMaximumSize, setMinimumSize, setOffsets, setPopup, setPositionScheme, setSelectable, setStyleClass, setTabIndex, setToolTip, setVerticalAlignment

Methods inherited from class eu.webtoolkit.jwt.WWidget

acceptDrops, acceptDrops, addCssRule, addCssRule, addStyleClass, animateHide, animateShow, containsExposed, disable, dropEvent, enable, getDrop, getJsRef, getParent, hide, htmlText, isLayoutSizeAware, isRendered, layoutSizeChanged, positionAt, positionAt, removeStyleClass, resize, setClearSides, setHeight, setHidden, setLayoutSizeAware, setMargin, setMargin, setMargin, setMargin, setMargin, setOffsets, setOffsets, setOffsets, setOffsets, setOffsets, setToolTip, setVerticalAlignment, setWidth, show, stopAcceptDrops, toggleStyleClass, toggleStyleClass, tr

Methods inherited from class eu.webtoolkit.jwt.WObject

addChild, getObjectName, setObjectName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WMenu

public WMenu(Orientation orientation,
             WContainerWidget parent)

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.

WMenu

public WMenu(Orientation orientation)

Creates a new menu.

Calls this(orientation, (WContainerWidget)null)

WMenu

public WMenu(WStackedWidget contentsStack,
             Orientation orientation,
             WContainerWidget parent)

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.

WMenu

public WMenu(WStackedWidget contentsStack,
             Orientation orientation)

Creates a new menu.

Calls this(contentsStack, orientation, (WContainerWidget)null)

Method Detail

remove

public void remove()

Destructor.

Overrides:

remove in class WCompositeWidget

See Also:

WContainerWidget.removeWidget(WWidget widget)

addItem

public WMenuItem addItem(java.lang.CharSequence name,
                         WWidget contents,
                         WMenuItem.LoadPolicy policy)

Adds an item.

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

contents may be null 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 item)

addItem

public final WMenuItem addItem(java.lang.CharSequence name,
                               WWidget contents)

Adds an item.

Returns addItem(name, contents, WMenuItem.LoadPolicy.LazyLoading)

addItem

public WMenuItem addItem(WMenuItem item)

Adds an item.

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

See Also:

addItem(CharSequence name, WWidget contents, WMenuItem.LoadPolicy policy)

removeItem

public void removeItem(WMenuItem item)

Removes an item.

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

See Also:

addItem(CharSequence name, WWidget contents, WMenuItem.LoadPolicy policy)

select

public void select(WMenuItem item)

Selects an item.

Select the menu item item.

When item is null, the current selection is removed.

See Also:

select(int index), getCurrentItem(), WMenuItem.select()

select

public void 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 item), getCurrentIndex()

itemSelected

public Signal1<WMenuItem> 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()

itemSelectRendered

public Signal1<WMenuItem> 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()

close

public void close(WMenuItem item)

Closes an item.

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

See Also:

close(int index), WMenuItem.close()

close

public void 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 item)

getItems

public java.util.List<WMenuItem> getItems()

Returns the items.

Returns the list of menu items in this menu.

itemClosed

public Signal1<WMenuItem> 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.

setItemHidden

public void setItemHidden(WMenuItem item,
                          boolean 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 index, boolean hidden), WMenuItem.hide()

setItemHidden

public void setItemHidden(int index,
                          boolean hidden)

Hides an item.

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

See Also:

setItemHidden(WMenuItem item, boolean hidden)

isItemHidden

public boolean isItemHidden(WMenuItem item)

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

See Also:

setItemHidden(WMenuItem item, boolean hidden)

isItemHidden

public boolean isItemHidden(int index)

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(WMenuItem item, boolean hidden)

setItemDisabled

public void setItemDisabled(WMenuItem item,
                            boolean 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 index, boolean disabled), WMenuItem.setDisabled(boolean disabled)

setItemDisabled

public void setItemDisabled(int index,
                            boolean disabled)

Disables an item.

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

See Also:

setItemDisabled(WMenuItem item, boolean disabled)

isItemDisabled

public boolean isItemDisabled(WMenuItem item)

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

See Also:

setItemDisabled(WMenuItem item, boolean disabled)

isItemDisabled

public boolean isItemDisabled(int index)

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(WMenuItem item, boolean disabled)

getCurrentItem

public WMenuItem getCurrentItem()

Returns the currently selected item.

See Also:

getCurrentIndex(), select(WMenuItem item)

getCurrentIndex

public int getCurrentIndex()

Returns the index of the currently selected item.

See Also:

getCurrentItem(), select(int index)

getOrientation

public Orientation getOrientation()

Returns the orientation.

The orientation is set at time of construction.

setRenderAsList

public void setRenderAsList(boolean 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.

renderAsList

public boolean renderAsList()

Returns whether the menu is rendered as an HTML list.

See Also:

setRenderAsList(boolean enable)

setInternalPathEnabled

public void setInternalPathEnabled(java.lang.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#getPathComponent() is appended to the basePath, which defaults to the internal path ( WApplication#getBookmarkUrl()). 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(String path)

setInternalPathEnabled

public final void setInternalPathEnabled()

Enables internal paths for items.

Calls setInternalPathEnabled("")

isInternalPathEnabled

public boolean isInternalPathEnabled()

Returns whether the menu generates internal paths entries.

See Also:

setInternalPathEnabled(String basePath)

setInternalBasePath

public void setInternalBasePath(java.lang.String basePath)

Sets the internal base path.

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

See Also:

setInternalPathEnabled(String basePath), getInternalBasePath()

getInternalBasePath

public java.lang.String getInternalBasePath()

Returns the internal base path.

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

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

See Also:

setInternalPathEnabled(String basePath)

getContentsStack

public WStackedWidget getContentsStack()

Returns the contents stack associated with the menu.

enableAjax

protected void enableAjax()

Description copied from class: WWidget

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.

Overrides:

enableAjax in class WCompositeWidget

See Also:

WApplication.enableAjax()

nextAfterHide

protected int nextAfterHide(int index)

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.