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package javax.swing.tree;
import java.awt.Component;
import javax.swing.JTree;
Defines the requirements for an object that displays a tree node.
See How to Use Trees
in The Java Tutorial
for an example of implementing a tree cell renderer
that displays custom icons.
Author: Rob Davis, Ray Ryan, Scott Violet
/**
* Defines the requirements for an object that displays a tree node.
* See <a
href="https://docs.oracle.com/javase/tutorial/uiswing/components/tree.html">How to Use Trees</a>
* in <em>The Java Tutorial</em>
* for an example of implementing a tree cell renderer
* that displays custom icons.
*
* @author Rob Davis
* @author Ray Ryan
* @author Scott Violet
*/
public interface TreeCellRenderer {
Sets the value of the current tree cell to value.
If selected is true, the cell will be drawn as if
selected. If expanded is true the node is currently
expanded and if leaf is true the node represents a
leaf and if hasFocus is true the node currently has
focus. tree is the JTree the receiver is being
configured for. Returns the Component that the renderer
uses to draw the value.
The TreeCellRenderer is also responsible for rendering the
the cell representing the tree's current DnD drop location if
it has one. If this renderer cares about rendering
the DnD drop location, it should query the tree directly to
see if the given row represents the drop location:
JTree.DropLocation dropLocation = tree.getDropLocation();
if (dropLocation != null
&& dropLocation.getChildIndex() == -1
&& tree.getRowForPath(dropLocation.getPath()) == row) {
// this row represents the current drop location
// so render it specially, perhaps with a different color
}
Params: - tree – the receiver is being configured for
- value – the value to render
- selected – whether node is selected
- expanded – whether node is expanded
- leaf – whether node is a lead node
- row – row index
- hasFocus – whether node has focus
Returns: the Component that the renderer uses to draw the value
/**
* Sets the value of the current tree cell to <code>value</code>.
* If <code>selected</code> is true, the cell will be drawn as if
* selected. If <code>expanded</code> is true the node is currently
* expanded and if <code>leaf</code> is true the node represents a
* leaf and if <code>hasFocus</code> is true the node currently has
* focus. <code>tree</code> is the <code>JTree</code> the receiver is being
* configured for. Returns the <code>Component</code> that the renderer
* uses to draw the value.
* <p>
* The <code>TreeCellRenderer</code> is also responsible for rendering the
* the cell representing the tree's current DnD drop location if
* it has one. If this renderer cares about rendering
* the DnD drop location, it should query the tree directly to
* see if the given row represents the drop location:
* <pre>
* JTree.DropLocation dropLocation = tree.getDropLocation();
* if (dropLocation != null
* && dropLocation.getChildIndex() == -1
* && tree.getRowForPath(dropLocation.getPath()) == row) {
*
* // this row represents the current drop location
* // so render it specially, perhaps with a different color
* }
* </pre>
*
* @param tree the receiver is being configured for
* @param value the value to render
* @param selected whether node is selected
* @param expanded whether node is expanded
* @param leaf whether node is a lead node
* @param row row index
* @param hasFocus whether node has focus
* @return the {@code Component} that the renderer uses to draw the value
*/
Component getTreeCellRendererComponent(JTree tree, Object value,
boolean selected, boolean expanded,
boolean leaf, int row, boolean hasFocus);
}