tree.html

jsf、swing的官方指南

</pre></blockquote>
<p>

Here is the code that the <b>Add</b> button's event handler
uses to add a new node to the tree:

<blockquote><pre>
treePanel.addObject("New Node " + newNodeSuffix++);
...
public DefaultMutableTreeNode addObject(Object child) {
    DefaultMutableTreeNode parentNode = null;
    TreePath parentPath = tree.getSelectionPath();

    if (parentPath == null) {
        //There's no selection. Default to the root node.
        parentNode = rootNode;
    } else {
        parentNode = (DefaultMutableTreeNode)
                     (parentPath.getLastPathComponent());
    }

    return addObject(parentNode, child, true);
}
...
public DefaultMutableTreeNode addObject(DefaultMutableTreeNode parent,
                                        Object child,
                                        boolean shouldBeVisible) {
    DefaultMutableTreeNode childNode =
            new DefaultMutableTreeNode(child);
    ...
    treeModel.insertNodeInto(childNode, parent,
                             parent.getChildCount());

    //Make sure the user can see the lovely new node.
    if (shouldBeVisible) {
        tree.scrollPathToVisible(new TreePath(childNode.getPath()));
    }
    return childNode;
}
</pre></blockquote>

The code creates a node,
inserts it into the tree model,
and then, if appropriate, requests that the nodes above it
be expanded and the tree scrolled so that the new node is visible.
To insert the node into the model, the code uses the 
<code>insertNodeInto</code> method provided by the 
<code>DefaultTreeModel</code> class.


</blockquote>
<h3>
<a name="data">
Creating a Data Model
</a>
</h3>
<blockquote>

If <code>DefaultTreeModel</code>
doesn't suit your needs,
then you'll need to write a custom data model.
Your data model must implement the 
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeModel.html"><code>TreeModel</code></a> interface.
<code>TreeModel</code> specifies methods for
getting a particular node of the tree,
getting the number of children of a particular node,
determining whether a node is a leaf,
notifying the model of a change in the tree,
and adding and removing tree model listeners.

<p>

Interestingly, the <code>TreeModel</code> interface
accepts any kind of object as a tree node.
It doesn't require that nodes be represented
by <code>DefaultMutableTreeNode</code> objects,
or even that nodes implement the 
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeNode.html"><code>TreeNode</code></a> interface.
Thus, if the <code>TreeNode</code> interface
isn't suitable for your tree model,
feel free to devise your own representation for tree nodes.
For example,
if you have a pre-existing hierarchical data structure,
you don't need to duplicate it
or force it into the <code>TreeNode</code> mold.
You just need to implement your tree model 
so that it uses the information in the existing data structure.

<p>
The following figure shows an application called
GenealogyExample
that displays the descendants or ancestors
of a particular person.
(Thanks to tutorial reader
Olivier Berlanger
for providing this example.)
You can <a href="http://java.sun.com/docs/books/tutorialJWS/uiswing/components/examples/GenealogyExample.jnlp">run GenealogyExample</a> (it requires release 6) using
<a class="TutorialLink" target="_top" href="../../information/javawebstart.html">Java Web Start</a>.    Or, to compile and run the example yourself,
     consult the
     <a href="examples/index.html#GenealogyExample">example index</a>.

<p>
<p><center><IMG SRC="../../figures/uiswing/components/GenealogyExample.png" WIDTH="268" HEIGHT="191" ALIGN="BOTTOM" ALT="GenealogyExample"></center></p>
<p>
You can find
the custom tree model implementation in 
<a class="SourceLink" target="_blank" href="examples/GenealogyModel.java"><code>GenealogyModel.java</code></a>.
Because the model
is implemented as an <code>Object</code> subclass
instead of, say, a subclass of <code>DefaultTreeModel</code>,
it must implement the <code>TreeModel</code> interface directly.
This requires implementing methods
for getting information about nodes,
such as which is the root
and what are the children of a particular node.
In the case of <code>GenealogyModel</code>,
each node is represented by an object of type <code>Person</code>,
a custom class that doesn't
implement <code>TreeNode</code>.

<p>
A tree model must also implement methods
for adding and removing tree model listeners,
and must fire <code>TreeModelEvent</code>s to those listeners
when the tree's structure or data changes.
For example, when the user instructs GenealogyExample
to switch from showing ancestors to showing descendants,
the tree model makes the change
and then fires an event to inform its listeners
(such as the tree component).


</blockquote>
<h3>
<a name="api">The Tree API</a>
</h3>
<blockquote>

The tree API is quite extensive.
The following tables list just a bit of the API,
concentrating on 
the following categories:

<ul>
<li><a href="#overviewapi">Tree-Related Classes and Interfaces</a>
<li><a href="#creatingapi">Creating and Setting Up a Tree</a>
<li><a href="#selectionapi">Implementing Selection</a>
<li><a href="#expandapi">Showing and Hiding Nodes</a>
</ul>

<p>

For more information about the tree API,
see the API documentation for 
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html"><code>JTree</code></a> and for the various classes and interfaces in the
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/package-summary.html">tree package</a>.
Also refer to <a href="jcomponent.html">The JComponent Class</a>
for information on the API <code>JTree</code> inherits
from its superclass.

<p>
<table border=1> 
<caption><a name="overviewapi">Tree-Related Classes and Interfaces</a></caption>
<tr>
<th align=left>Class or Interface
</th>
<th align=left>Purpose
 
</th>
</tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html">JTree</a>    </td>
    <td>The component that presents the tree to the user.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreePath.html">TreePath</a>    </td>
    <td>Represents a path to a node.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeNode.html">TreeNode</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/MutableTreeNode.html">MutableTreeNode</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/DefaultMutableTreeNode.html">DefaultMutableTreeNode</a>    </td>
    <td>The interfaces that the default tree model
        expects its tree nodes to implement,
        and the implementation used by the default tree model.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeModel.html">TreeModel</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/DefaultTreeModel.html">DefaultTreeModel</a>    </td>
    <td>Respectively, the interface that a tree model must implement
        and the usual implementation used.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeCellRenderer.html">TreeCellRenderer</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/DefaultTreeCellRenderer.html">DefaultTreeCellRenderer</a>    </td>
    <td>Respectively, the interface that a tree cell renderer must implement
        and the usual implementation used.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeCellEditor.html">TreeCellEditor</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/DefaultTreeCellEditor.html">DefaultTreeCellEditor</a>    </td>
    <td>Respectively, the interface that a tree cell editor must implement
        and the usual implementation used.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeSelectionModel.html">TreeSelectionModel</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/DefaultTreeSelectionModel.html">DefaultTreeSelectionModel</a>    </td>
    <td>Respectively, the interface that the tree's selection model 
        must implement and the usual implementation used.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/TreeSelectionListener.html">TreeSelectionListener</a>   <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/TreeSelectionEvent.html">TreeSelectionEvent</a>    </td>
    <td>The interface and event type used for detecting
        tree selection changes.
        For more information, see 
<a class="TutorialLink" target="_top" href="../events/treeselectionlistener.html ">Getting Started</a>.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/TreeModelListener.html">TreeModelListener</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/TreeModelEvent.html">TreeModelEvent</a>    </td>
    <td>The interface and event type used for detecting
        tree model changes.
        For more information, see 
<a class="TutorialLink" target="_top" href="../events/treemodellistener.html">How to Write a Tree Model Listener</a>.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/TreeExpansionListener.html">TreeExpansionListener</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/TreeWillExpandListener.html">TreeWillExpandListener</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/TreeExpansionEvent.html">TreeExpansionEvent</a>    </td>
    <td>The interfaces and event type used for detecting
        tree expansion and collapse.
        For more information, see 
<a class="TutorialLink" target="_top" href="../events/treeexpansionlistener.html">How to Write a Tree Expansion Listener</a>    and
<a class="TutorialLink" target="_top" href="../events/treewillexpandlistener.html">How to Write a Tree-Will-Expand Listener</a>.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/ExpandVetoException.html">ExpandVetoException</a>    </td>
    <td>An exception that a <code>TreeWillExpandListener</code>
        can throw to indicate that the impending expansion/collapse
        should not happen.
        For more information, see 
<a class="TutorialLink" target="_top" href="../events/treewillexpandlistener.html">How to Write a Tree-Will-Expand Listener</a>.
    </td>
  </tr>
</table>

<p>
<table border=1> 
<caption><a name="creatingapi">Creating and Setting Up a Tree</a></caption>
<tr>
<th align=left>Constructor or Method
</th>
<th align=left>Purpose
 
</th>
</tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#JTree(javax.swing.tree.TreeNode)">JTree(TreeNode)</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#JTree(javax.swing.tree.TreeNode, boolean)">JTree(TreeNode, boolean)</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#JTree(javax.swing.tree.TreeModel)">JTree(TreeModel)</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#JTree()">JTree()</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#JTree(java.util.Hashtable)">JTree(Hashtable)</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#JTree(java.lang.Object[])">JTree(Object[])</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#JTree(java.util.Vector)">JTree(Vector)</a>    </td>
    <td>Create a tree.
        The <code>TreeNode</code> argument
        specifies the root node,
        to be managed by the default tree model.
        The <code>TreeModel</code> argument 
        specifies the model that provides the data to the table.
        The no-argument version of this constructor
        is for use in builders;
        it creates a tree that contains some sample data.
        If you specify a <code>Hashtable</code>,
        array of objects, of <code>Vector</code>
        as an argument, 
        then the argument is treated as a list of nodes
        under the root node (which is not displayed),
        and a model and tree nodes are constructed accordingly.

	<p>
        The <code>boolean</code> argument,
	if present, specifies
        how the tree should determine 
	whether a node should be displayed as a leaf.
	If the argument is false (the default),
	any node without children is diaplayed as a leaf.
	If the argument is true,
	a node is a leaf only if its
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/tree/TreeNode.html#getAllowsChildren()"><code>getAllowsChildren</code></a>	method returns false.
    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#setCellRenderer(javax.swing.tree.TreeCellRenderer)">void setCellRenderer(TreeCellRenderer)</a>    </td>
    <td>Set the renderer that draws each node.

    </td>
  </tr>
  <tr>
    <td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#setEditable(boolean)">void setEditable(boolean)</a>    <br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTree.html#setCellEditor(javax.swing.tree.TreeCellEditor)">void setCellEditor(TreeCellEditor)</a>    </td>