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Wt::WTreeNode Class Reference

A single node in a tree. More...

#include <Wt/WTreeNode>

Inheritance diagram for Wt::WTreeNode:
Inheritance graph
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Public Types

enum  LoadPolicy { LazyLoading, PreLoading, NextLevelLoading }
 An enumeration for the policy to load children. More...
 
enum  ChildCountPolicy { Disabled, Enabled, Lazy }
 An enumeration for the policy to display the child count. More...
 

Public Member Functions

 WTreeNode (const WString &labelText, WIconPair *labelIcon=0, WTreeNode *parentNode=0)
 Creates a tree node with the given label. More...
 
 ~WTreeNode ()
 Destructor.
 
virtual WTreetree () const
 Returns the tree. More...
 
WTextlabel () const
 Returns the label.
 
WIconPairlabelIcon () const
 Returns the label icon.
 
void setLabelIcon (WIconPair *labelIcon)
 Sets the label icon.
 
virtual void insertChildNode (int index, WTreeNode *node)
 Inserts a child node. More...
 
void addChildNode (WTreeNode *node)
 Adds a child node. More...
 
void removeChildNode (WTreeNode *node)
 Removes a child node. More...
 
const std::vector< WTreeNode * > & childNodes () const
 Returns the list of children.
 
virtual int displayedChildCount () const
 Returns the number of children that should be displayed. More...
 
void setChildCountPolicy (ChildCountPolicy policy)
 Configures how and when the child count should be displayed. More...
 
ChildCountPolicy childCountPolicy () const
 Returns the child count policy. More...
 
void setImagePack (const std::string &url)
 Sets the image pack for this (sub)tree (deprecated). More...
 
void setLoadPolicy (LoadPolicy loadPolicy)
 Sets the load policy for this tree. More...
 
bool isExpanded () const
 Returns whether this node is expanded.
 
void setSelectable (bool selectable)
 Allows this node to be selected. More...
 
virtual bool isSelectable () const
 Returns if this node may be selected. More...
 
WTreeNodeparentNode () const
 Returns the parent node. More...
 
void setNodeVisible (bool visible)
 Sets the visibility of the node itself. More...
 
void setChildrenDecorated (bool decorated)
 Sets whether this node's children are decorated. More...
 
void setInteractive (bool interactive)
 Sets whether this node is interactive. More...
 
void expand ()
 Expands this node. More...
 
void collapse ()
 Collapses this node. More...
 
EventSignal< WMouseEvent > & expanded ()
 Signal emitted when the node is expanded by the user. More...
 
EventSignal< WMouseEvent > & collapsed ()
 Signal emitted when the node is collapsed by the user. More...
 
Signal< bool > & selected ()
 Signal that is emitted when the node is added or removed from the selection More...
 
- Public Member Functions inherited from Wt::WCompositeWidget
 WCompositeWidget (WContainerWidget *parent=0)
 Creates a WCompositeWidget. More...
 
 WCompositeWidget (WWidget *implementation, WContainerWidget *parent)
 Creates a WCompositeWidget with given implementation. More...
 
virtual void setObjectName (const std::string &name)
 Sets an object name. More...
 
virtual std::string objectName () const
 Returns the object name. More...
 
virtual const std::string id () const
 Returns the (unique) identifier for this object. More...
 
virtual void setPositionScheme (PositionScheme scheme)
 Sets the CSS position scheme. More...
 
virtual PositionScheme positionScheme () const
 Returns the CSS position scheme. More...
 
virtual void setOffsets (const WLength &offset, WFlags< Side > sides=All)
 Sets CSS offsets for a non-statically positioned widget. More...
 
virtual WLength offset (Side s) const
 Returns a CSS offset. More...
 
virtual void resize (const WLength &width, const WLength &height)
 Resizes the widget. More...
 
virtual WLength width () const
 Returns the width. More...
 
virtual WLength height () const
 Returns the height. More...
 
virtual void setMinimumSize (const WLength &width, const WLength &height)
 Sets a minimum size. More...
 
virtual WLength minimumWidth () const
 Returns the minimum width. More...
 
virtual WLength minimumHeight () const
 Returns the minimum height. More...
 
virtual void setMaximumSize (const WLength &width, const WLength &height)
 Sets a maximum size. More...
 
virtual WLength maximumWidth () const
 Returns the maximum width. More...
 
virtual WLength maximumHeight () const
 Returns the maximum height. More...
 
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. More...
 
virtual void setFloatSide (Side s)
 Specifies a CSS float side. More...
 
virtual Side floatSide () const
 Returns the CSS float side. More...
 
virtual void setClearSides (WFlags< Side > sides)
 Sets the sides that should be cleared of floats. More...
 
virtual WFlags< SideclearSides () const
 Returns the sides that should remain empty. More...
 
virtual void setMargin (const WLength &margin, WFlags< Side > sides=All)
 Sets CSS margins around the widget. More...
 
virtual WLength margin (Side side) const
 Returns a CSS margin set. More...
 
virtual void setHiddenKeepsGeometry (bool enabled)
 Sets whether the widget keeps its geometry when hidden. More...
 
virtual bool hiddenKeepsGeometry () const
 Returns whether the widget keeps its geometry when hidden. More...
 
virtual void setHidden (bool hidden, const WAnimation &animation=WAnimation())
 Hides or shows the widget. More...
 
virtual bool isHidden () const
 Returns whether the widget is set hidden. More...
 
virtual bool isVisible () const
 Returns whether the widget is visible. More...
 
virtual void setDisabled (bool disabled)
 Sets whether the widget is disabled. More...
 
virtual bool isDisabled () const
 Returns whether the widget is set disabled. More...
 
virtual bool isEnabled () const
 Returns whether the widget is enabled. More...
 
virtual void setPopup (bool popup)
 Lets the widget overlay over other sibling widgets. More...
 
virtual bool isPopup () const
 Returns whether the widget is overlayed. More...
 
virtual void setInline (bool isInline)
 Sets whether the widget is displayed inline or as a block. More...
 
virtual bool isInline () const
 Returns whether the widget is displayed inline or as block. More...
 
virtual void setDecorationStyle (const WCssDecorationStyle &style)
 Sets a CSS decoration style. More...
 
virtual WCssDecorationStyledecorationStyle ()
 Returns the decoration style of this widget. More...
 
virtual void setStyleClass (const WString &styleClass)
 Sets (one or more) CSS style classes. More...
 
virtual WString styleClass () const
 Returns the CSS style class. More...
 
virtual void addStyleClass (const WString &styleClass, bool force=false)
 Adds a CSS style class. More...
 
virtual void removeStyleClass (const WString &styleClass, bool force=false)
 Removes a CSS style class. More...
 
virtual bool hasStyleClass (const WString &styleClass) const
 Returns whether the widget has a style class.
 
virtual void setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength::Auto)
 Sets the vertical alignment. More...
 
virtual AlignmentFlag verticalAlignment () const
 Returns the vertical alignment. More...
 
virtual WLength verticalAlignmentLength () const
 Returns the fixed vertical alignment that was set. More...
 
virtual void setToolTip (const WString &text, TextFormat textFormat=PlainText)
 Sets a tooltip. More...
 
virtual WString toolTip () const
 Returns the tooltip.
 
virtual void setDeferredToolTip (bool enable, TextFormat textFormat=PlainText)
 Enable deferred tooltip. More...
 
virtual void refresh ()
 Refresh the widget. More...
 
virtual void setAttributeValue (const std::string &name, const WString &value)
 Sets an attribute value. More...
 
virtual WString attributeValue (const std::string &name) const
 Returns an attribute value. More...
 
virtual void setJavaScriptMember (const std::string &name, const std::string &value)
 Sets a JavaScript member. More...
 
virtual std::string javaScriptMember (const std::string &name) const
 Returns the value of a JavaScript member. More...
 
virtual void callJavaScriptMember (const std::string &name, const std::string &args)
 Calls a JavaScript member. More...
 
virtual void load ()
 Loads content just before the widget is used. More...
 
virtual bool loaded () const
 Returns whether this widget has been loaded. More...
 
virtual void setCanReceiveFocus (bool enabled)
 Sets whether the widget can receive focus. More...
 
virtual bool canReceiveFocus () const
 Returns whether the widget can receive focus. More...
 
virtual void setFocus (bool focus)
 Sets focus. More...
 
virtual bool setFirstFocus ()
 Set focus on the widget's first descendant. More...
 
virtual bool hasFocus () const
 Returns whether the widget currently has the focus.
 
virtual void setTabIndex (int index)
 Sets the tab index. More...
 
virtual int tabIndex () const
 Returns the tab index. More...
 
virtual void setId (const std::string &id)
 Sets the CSS Id. More...
 
virtual WWidgetfind (const std::string &name)
 Finds a descendent widget by name. More...
 
virtual WWidgetfindById (const std::string &name)
 Finds a descendent widget by id.
 
virtual void doJavaScript (const std::string &js)
 Executes the given JavaScript statements when the widget is rendered or updated. More...
 
virtual void propagateSetEnabled (bool enabled)
 Propagates that a widget was enabled or disabled through children. More...
 
- Public Member Functions inherited from Wt::WWidget
virtual ~WWidget ()
 Destructor. More...
 
WWidgetparent () const
 Returns the parent widget. More...
 
virtual void removeChild (WObject *child)
 Removes a child object. More...
 
void setWidth (const WLength &width)
 Sets the width. More...
 
void setHeight (const WLength &height)
 Sets the height. More...
 
virtual void positionAt (const WWidget *widget, Orientation orientation=Vertical)
 Positions a widget next to another widget. More...
 
virtual void toggleStyleClass (const WString &styleClass, bool add, bool force=false)
 Toggles a CSS style class.
 
std::string jsRef () const
 Returns a JavaScript expression to the corresponding DOM node. More...
 
void setFocus ()
 Sets focus. More...
 
virtual void acceptDrops (const std::string &mimeType, const WString &hoverStyleClass=WString())
 Sets a mime type to be accepted for dropping. More...
 
virtual void stopAcceptDrops (const std::string &mimeType)
 Indicates that a mime type is no longer accepted for dropping. More...
 
virtual void htmlText (std::ostream &out)
 Streams the (X)HTML representation. More...
 
bool isRendered () const
 Returns whether the widget is rendered. More...
 
void hide ()
 Hides the widget. More...
 
void animateHide (const WAnimation &animation)
 Hides the widget using an animation. More...
 
void show ()
 Shows the widget. More...
 
void animateShow (const WAnimation &animation)
 Shows the widget using an animation. More...
 
void enable ()
 Enables the widget. More...
 
void disable ()
 Disable thes widget. More...
 
bool layoutSizeAware () const
 Returns whether the widget is layout size aware. More...
 
- Public Member Functions inherited from Wt::WObject
 WObject (WObject *parent=0)
 Create a WObject with a given parent object. More...
 
virtual ~WObject ()
 Destructor. More...
 
void resetLearnedSlots ()
 Resets learned stateless slot implementations. More...
 
template<class T >
void resetLearnedSlot (void(T::*method)())
 Resets a learned stateless slot implementation. More...
 
template<class T >
WStatelessSlot * implementStateless (void(T::*method)())
 Declares a slot to be stateless and learn client-side behaviour on first invocation. More...
 
template<class T >
WStatelessSlot * implementStateless (void(T::*method)(), void(T::*undoMethod)())
 Declares a slot to be stateless and learn client-side behaviour in advance. More...
 
template<class T >
WStatelessSlot * implementJavaScript (void(T::*method)(), const std::string &jsCode)
 Provides a JavaScript implementation for a method. More...
 
void addChild (WObject *child)
 Adds a child object. More...
 
const std::vector< WObject * > & children () const
 Returns the children.
 
WObjectparent () const
 Returns the parent object.
 

Protected Member Functions

 WTreeNode (WTreeNode *parentNode=0)
 Creates a tree node with empty labelArea(). More...
 
WContainerWidgetlabelArea ()
 Accesses the container widget that holds the label area. More...
 
virtual void populate ()
 Populates the node dynamically on loading. More...
 
bool populated () const
 Returns whether this node has already been populated. More...
 
virtual bool expandable ()
 Returns whether this node can be expanded. More...
 
virtual void renderSelected (bool selected)
 Renders the node to be selected. More...
 
std::string imagePack () const
 The image pack that is used for this tree node (deprecated). More...
 
virtual void descendantRemoved (WTreeNode *node)
 Reacts to the removal of a descendant node. More...
 
virtual void descendantAdded (WTreeNode *node)
 Reacts to the addition of a descendant node. More...
 
virtual void doExpand ()
 The actual expand. More...
 
virtual void doCollapse ()
 The actual collapse. More...
 
virtual void undoDoExpand ()
 Undo method for doCollapse() stateless implementation. More...
 
virtual void undoDoCollapse ()
 Undo method for doCollapse() stateless implementation. More...
 
WIconPairexpandIcon () const
 Accesses the icon pair that allows expansion of the tree node.
 
- Protected Member Functions inherited from Wt::WCompositeWidget
virtual void enableAjax ()
 Progresses to an Ajax-enabled widget. More...
 
void setImplementation (WWidget *widget)
 Set the implementation widget. More...
 
WWidgetimplementation ()
 Get the implementation widget. More...
 
virtual int boxPadding (Orientation orientation) const
 Returns the widget's built-in padding. More...
 
virtual int boxBorder (Orientation orientation) const
 Returns the widget's built-in border width. More...
 
virtual void render (WFlags< RenderFlag > flags)
 Renders the widget. More...
 
- 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. More...
 
virtual void layoutSizeChanged (int width, int height)
 Virtual method that indicates a size change. More...
 
 WWidget (WContainerWidget *parent=0)
 Creates a widget. More...
 
virtual void dropEvent (WDropEvent dropEvent)
 Handles a drop event. More...
 
void scheduleRender (WFlags< RepaintFlag > flags=0)
 Schedules rerendering of the widget. More...
 
virtual WStatelessSlot * getStateless (Method method)
 On-demand stateless slot implementation. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from Wt::WWidget
static WString tr (const char *key)
 Short hand for WString::tr() More...
 
- Static Protected Member Functions inherited from Wt::WObject
static WObjectsender ()
 Returns the sender of the current slot call. More...
 

Detailed Description

A single node in a tree.

A tree list is constructed by combining several tree node objects in a tree hierarchy, by passing the parent tree node as the last argument in the child node constructor, or by using addChildNode(), to add a child to its parent.

Each tree node has a label, and optionally a label icon pair. The icon pair offers the capability to show a different icon depending on the state of the node (expanded or collapsed). When the node has any children, a child count may be displayed next to the label using setChildCountPolicy().

Expanding a tree node it will collapse all its children, so that a user may collapse/expand a node as a short-cut to collapsing all children.

The treenode provides several policies to communicate the current contents of the tree to the client (if possible):

The default policy is WTreeNode::LazyLoading. Another load policy may be specified using setLoadPolicy() on the root node and before adding any children. The load policy is inherited by all children in the tree.

There are a few scenarios where it makes sense to specialize the WTreeNode class. One scenario is create a tree that is populated dynamically while browsing. For this purpose you should reimplement the populate() method, whose default implementation does nothing. This method is called when 'loading' the node. The exact moment for loading a treenode depends on the LoadPolicy.

A second scenario that is if you want to customize the look of the tree label (see labelArea()) or if you want to modify or augment the event collapse/expand event handling (see doExpand() and doCollapse()).

See WTree for a usage example.

See Also
WTree, WTreeTableNode

Member Enumeration Documentation

An enumeration for the policy to display the child count.

Enumerator
Disabled 

Do not display a child count.

Enabled 

Always display a child count.

Lazy 

Only display a child count when the node is populated.

An enumeration for the policy to load children.

Enumerator
LazyLoading 

Load-on-demand of child nodes.

PreLoading 

Pre-load all child nodes.

NextLevelLoading 

Pre-load one level of child nodes.

Constructor & Destructor Documentation

Wt::WTreeNode::WTreeNode ( const WString labelText,
WIconPair labelIcon = 0,
WTreeNode parentNode = 0 
)

Creates a tree node with the given label.

The labelIcon, if specified, will appear just before the label and its state reflect the expand/collapse state of the node.

The node is initialized to be collapsed.

Wt::WTreeNode::WTreeNode ( WTreeNode parentNode = 0)
protected

Creates a tree node with empty labelArea().

This tree node has no label or labelicon, and is therefore ideally suited to provide a custom look.

Member Function Documentation

void Wt::WTreeNode::addChildNode ( WTreeNode node)

Adds a child node.

Equivalent to:

insertChildNode(childNodes().size(), node);
See Also
insertChildNode()
ChildCountPolicy Wt::WTreeNode::childCountPolicy ( ) const

Returns the child count policy.

See Also
setChildCountPolicy(ChildCountPolicy policy)
void Wt::WTreeNode::collapse ( )

Collapses this node.

See Also
expand()
doCollapse()
EventSignal< WMouseEvent > & Wt::WTreeNode::collapsed ( )

Signal emitted when the node is collapsed by the user.

See Also
expanded()
void Wt::WTreeNode::descendantAdded ( WTreeNode node)
protectedvirtual

Reacts to the addition of a descendant node.

Reimplement this method if you wish to react on the addition of a descendant node. The default implementation simply propagates the event to the parent.

void Wt::WTreeNode::descendantRemoved ( WTreeNode node)
protectedvirtual

Reacts to the removal of a descendant node.

Reimplement this method if you wish to react on the removal of a descendant node. The default implementation simply propagates the event to the parent.

int Wt::WTreeNode::displayedChildCount ( ) const
virtual

Returns the number of children that should be displayed.

This is used to display the count in the count label. The default implementation simply returns childNodes().size().

void Wt::WTreeNode::doCollapse ( )
protectedvirtual

The actual collapse.

This method, which is implemented as a stateless slot, performs the actual collapse of the node.

You may want to reimplement this function (and undoDoCollapse()) if you wish to do additional things on node expansion.

See Also
doExpand()
collapse()
void Wt::WTreeNode::doExpand ( )
protectedvirtual

The actual expand.

This method, which is implemented as a stateless slot, performs the actual expansion of the node.

You may want to reimplement this function (and undoDoExpand()) if you wish to do additional things on node expansion.

See Also
doCollapse()
expand()
void Wt::WTreeNode::expand ( )

Expands this node.

Besides the actual expansion of the node, this may also trigger the loading and population of the node children, or of the children's children.

See Also
collapse()
doExpand()
bool Wt::WTreeNode::expandable ( )
protectedvirtual

Returns whether this node can be expanded.

The default implementation populates the node if necessary, and then checks if there are any child nodes.

You may wish to reimplement this method if you reimplement populate(), and you have a quick default for determining whether a node may be expanded (which does not require populating the node).

See Also
populate()
EventSignal< WMouseEvent > & Wt::WTreeNode::expanded ( )

Signal emitted when the node is expanded by the user.

See Also
collapsed()
std::string Wt::WTreeNode::imagePack ( ) const
protected

The image pack that is used for this tree node (deprecated).

Deprecated:
This method returns "" since Wt 3.1.1, as the image pack is no longer used in favour of the CSS themes.
void Wt::WTreeNode::insertChildNode ( int  index,
WTreeNode node 
)
virtual

Inserts a child node.

Inserts the node node at index index.

Reimplemented in Wt::WTreeTableNode.

virtual bool Wt::WTreeNode::isSelectable ( ) const
virtual

Returns if this node may be selected.

See Also
setSelectable(bool)
WContainerWidget * Wt::WTreeNode::labelArea ( )
protected

Accesses the container widget that holds the label area.

Use this to customize how the label should look like.

WTreeNode* Wt::WTreeNode::parentNode ( ) const

Returns the parent node.

See Also
childNodes()
void Wt::WTreeNode::populate ( )
protectedvirtual

Populates the node dynamically on loading.

Reimplement this method if you want to populate the widget dynamically, as the tree is being browsed and therefore loaded. This is only usefull with LazyLoading or NextLevelLoading strategies.

bool Wt::WTreeNode::populated ( ) const
protected

Returns whether this node has already been populated.

See Also
populate()
void Wt::WTreeNode::removeChildNode ( WTreeNode node)

Removes a child node.

The child node itself is not deleted

void Wt::WTreeNode::renderSelected ( bool  selected)
protectedvirtual

Renders the node to be selected.

The default implementation changes the style class of the labelArea() to "selected".

Signal<bool>& Wt::WTreeNode::selected ( )

Signal that is emitted when the node is added or removed from the selection

See Also
WTree::itemSelectionChanged
void Wt::WTreeNode::setChildCountPolicy ( ChildCountPolicy  policy)

Configures how and when the child count should be displayed.

By default, no child count indication is disabled (this is the behaviour since 2.1.1). Use this method to enable child count indications.

The child count policy is inherited by all children in the tree.

void Wt::WTreeNode::setChildrenDecorated ( bool  decorated)

Sets whether this node's children are decorated.

By default, node's children have expand/collapse and other lines to display their linkage and offspring.

By setting decorated to false, you can hide the decorations for the node's children.

void Wt::WTreeNode::setImagePack ( const std::string &  url)

Sets the image pack for this (sub)tree (deprecated).

Deprecated:
This method does not do anything since Wt 3.1.1, as the tree is now styled based on the current CSS theme.
void Wt::WTreeNode::setInteractive ( bool  interactive)

Sets whether this node is interactive.

Interactive nodes can be clicked upon and will populate a list of children when clicked. By disabling the interactivity, a node will not react to a click event.

void Wt::WTreeNode::setLoadPolicy ( LoadPolicy  loadPolicy)

Sets the load policy for this tree.

This may only be set on the root of a tree, and before adding any children.

void Wt::WTreeNode::setNodeVisible ( bool  visible)

Sets the visibility of the node itself.

If false, then the node itself is not displayed, but only its children. This is typically used to hide the root node of a tree.

void Wt::WTreeNode::setSelectable ( bool  selectable)
virtual

Allows this node to be selected.

By default, all nodes may be selected.

See Also
isSelectable(), WTree::select(WTreeNode *, bool)

Reimplemented from Wt::WCompositeWidget.

WTree * Wt::WTreeNode::tree ( ) const
virtual

Returns the tree.

By default if this node has no parent the result will be 0.

void Wt::WTreeNode::undoDoCollapse ( )
protectedvirtual

Undo method for doCollapse() stateless implementation.

See Also
doExpand()
void Wt::WTreeNode::undoDoExpand ( )
protectedvirtual

Undo method for doCollapse() stateless implementation.

See Also
doCollapse()

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