#include <WTreeNode>
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 Slots | |
void | expand () |
Expand this node. | |
void | collapse () |
Collapse this node. | |
Public Member Functions | |
WTreeNode (const WString &labelText, WIconPair *labelIcon=0, WTreeNode *parentNode=0) | |
Construct a tree node with the given label. | |
~WTreeNode () | |
Destructor. | |
WText * | label () const |
Get a reference to the label. | |
WIconPair * | labelIcon () const |
Get a reference to the label icon. | |
void | setLabelIcon (WIconPair *labelIcon) |
Change the label icon. | |
virtual void | addChildNode (WTreeNode *node) |
Add a child node. | |
void | removeChildNode (WTreeNode *node) |
Remove a child node. | |
const std::vector < WTreeNode * > & | childNodes () const |
Get the list of children. | |
virtual int | displayedChildCount () const |
Get the number of children that should be displayed. | |
void | setChildCountPolicy (ChildCountPolicy policy) |
Configure how and when the child count should be displayed. | |
ChildCountPolicy | childCountPolicy () const |
Get the child count policy. | |
void | setImagePack (const std::string &url) |
Set the image pack for this (sub)tree. | |
void | setLoadPolicy (LoadPolicy loadPolicy) |
Change the load policy for this tree. | |
bool | isExpanded () const |
Is this node expanded ? | |
void | setSelectable (bool selectable) |
Allow this node to be selected. | |
virtual bool | isSelectable () const |
Return if this node may be selected. | |
WTreeNode * | parentNode () const |
Return the parent node. | |
void | setNodeVisible (bool visible) |
Set the visibility of the node itself. | |
Public Attributes | |
EventSignal< void > | expanded |
Signal emitted when the node is expanded by the user. | |
EventSignal< void > | collapsed |
Signal emitted when the node is collapsed by the user. | |
Signal< bool > | selected |
Signal that is emitted when the node is added or removed from the selection | |
Protected Slots | |
virtual void | doExpand () |
The actual expand. | |
virtual void | doCollapse () |
The actual collapse. | |
Protected Member Functions | |
WTreeNode (WTreeNode *parentNode=0) | |
Construct a tree node with empty labelArea(). | |
WTableCell * | labelArea () |
Access the container widget that holds the label area. | |
virtual void | populate () |
Populate the node dynamically on loading. | |
bool | populated () const |
Returns whether this node has already been populated. | |
virtual bool | expandable () |
Returns whether this node can be expanded. | |
virtual void | renderSelected (bool selected) |
Render the node to be selected. | |
std::string | imagePack () const |
The image pack that is used for this tree node. | |
virtual void | descendantRemoved (WTreeNode *node) |
React to the removal of a descendant node. | |
virtual void | descendantAdded (WTreeNode *node) |
React to the addition of a descendant node. | |
virtual void | undoDoExpand () |
Undo method for doCollapse() stateless implementation. | |
virtual void | undoDoCollapse () |
Undo method for doCollapse() stateless implementation. |
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()).
Next to the icons, two style classes determine the look of a WTreeNode: the label has CSS style class "treenodelabel", and the child count has CSS style class "treenodechildcount".
For example, the following CSS stylesheet styles a tree for which the root has style class "mytree":
mytree * .treenodelabel { font-size: smaller; } mytree * .treenodechildcount { font-size: smaller; color: blue; }
The tree node uses an image-pack, which is a collection of images to render the expand/collapse icons and lines. Use setImagePack() to specify the location of these icons. This needs only be done on the root of the tree, as child nodes will query their ancestors for the location of these images, when they are not set explicitly.
Wt::WTreeNode::WTreeNode | ( | const WString & | labelText, | |
WIconPair * | labelIcon = 0 , |
|||
WTreeNode * | parentNode = 0 | |||
) |
Construct 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] |
Construct a tree node with empty labelArea().
This tree node has no label or labelicon, and is therefore ideally suited to provide a custom look.
int Wt::WTreeNode::displayedChildCount | ( | ) | const [virtual] |
Get 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::setChildCountPolicy | ( | ChildCountPolicy | policy | ) |
Configure 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.
ChildCountPolicy Wt::WTreeNode::childCountPolicy | ( | ) | const [inline] |
void Wt::WTreeNode::setImagePack | ( | const std::string & | url | ) |
Set the image pack for this (sub)tree.
You must specify a valid url for the directory that contains the icons.
void Wt::WTreeNode::setLoadPolicy | ( | LoadPolicy | loadPolicy | ) |
Change 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::setSelectable | ( | bool | selectable | ) |
Allow this node to be selected.
By default, all nodes may be selected.
virtual bool Wt::WTreeNode::isSelectable | ( | ) | const [inline, virtual] |
WTreeNode* Wt::WTreeNode::parentNode | ( | ) | const [inline] |
void Wt::WTreeNode::setNodeVisible | ( | bool | visible | ) |
Set 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.
WTableCell * Wt::WTreeNode::labelArea | ( | ) | [protected] |
Access the container widget that holds the label area.
Use this to customize how the label should look like.
void Wt::WTreeNode::populate | ( | ) | [protected, virtual] |
Populate 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 [inline, protected] |
bool Wt::WTreeNode::expandable | ( | ) | [protected, virtual] |
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).
void Wt::WTreeNode::renderSelected | ( | bool | selected | ) | [protected, virtual] |
Render the node to be selected.
The default implementation changes the style class of the labelArea() to "selected".
std::string Wt::WTreeNode::imagePack | ( | ) | const [protected] |
The image pack that is used for this tree node.
This is the imagepack that was set, or if not set, the image pack of its parent.
void Wt::WTreeNode::descendantRemoved | ( | WTreeNode * | node | ) | [protected, virtual] |
React 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.
void Wt::WTreeNode::descendantAdded | ( | WTreeNode * | node | ) | [protected, virtual] |
React 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::expand | ( | ) | [slot] |
Expand 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.
void Wt::WTreeNode::collapse | ( | ) | [slot] |
void Wt::WTreeNode::doExpand | ( | ) | [protected, virtual, slot] |
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.
void Wt::WTreeNode::doCollapse | ( | ) | [protected, virtual, slot] |
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.
void Wt::WTreeNode::undoDoExpand | ( | ) | [protected, virtual] |
void Wt::WTreeNode::undoDoCollapse | ( | ) | [protected, virtual] |
Signal that is emitted when the node is added or removed from the selection