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SampleTreeCellRenderer.javaAPI DocSun JDK 1.4.2 Example5536Thu May 12 00:35:28 BST 2005None

SampleTreeCellRenderer

public class SampleTreeCellRenderer extends JLabel implements TreeCellRenderer

Fields Summary
protected static Font
defaultFont
Font used if the string to be displayed isn't a font.
protected static ImageIcon
collapsedIcon
Icon to use when the item is collapsed.
protected static ImageIcon
expandedIcon
Icon to use when the item is expanded.
protected static final Color
SelectedBackgroundColor
Color to use for the background when selected.
protected boolean
selected
Whether or not the item that was last configured is selected.
Constructors Summary
Methods Summary
public java.awt.ComponentgetTreeCellRendererComponent(javax.swing.JTree tree, java.lang.Object value, boolean selected, boolean expanded, boolean leaf, int row, boolean hasFocus)
This is messaged from JTree whenever it needs to get the size of the component or it wants to draw it. This attempts to set the font based on value, which will be a TreeNode.

	Font            font;
	String          stringValue = tree.convertValueToText(value, selected,
					   expanded, leaf, row, hasFocus);

	/* Set the text. */
	setText(stringValue);
	/* Tooltips used by the tree. */
	setToolTipText(stringValue);

	/* Set the image. */
	if(expanded)
	    setIcon(expandedIcon);
	else if(!leaf)
	    setIcon(collapsedIcon);
	else
	    setIcon(null);

	/* Set the color and the font based on the SampleData userObject. */
	SampleData         userObject = (SampleData)((DefaultMutableTreeNode)value)
	                                .getUserObject();
	if(hasFocus)
	    setForeground(Color.cyan);
	else
	    setForeground(userObject.getColor());
	if(userObject.getFont() == null)
	    setFont(defaultFont);
	else
	    setFont(userObject.getFont());

	/* Update the selected flag for the next paint. */
	this.selected = selected;

	return this;
public voidpaint(java.awt.Graphics g)
paint is subclassed to draw the background correctly. JLabel currently does not allow backgrounds other than white, and it will also fill behind the icon. Something that isn't desirable.

	Color            bColor;
	Icon             currentI = getIcon();

	if(selected)
	    bColor = SelectedBackgroundColor;
	else if(getParent() != null)
	    /* Pick background color up from parent (which will come from
	       the JTree we're contained in). */
	    bColor = getParent().getBackground();
	else
	    bColor = getBackground();
	g.setColor(bColor);
	if(currentI != null && getText() != null) {
	    int          offset = (currentI.getIconWidth() + getIconTextGap());

            if (getComponentOrientation().isLeftToRight()) {
                g.fillRect(offset, 0, getWidth() - 1 - offset,
                           getHeight() - 1);
            }
            else {
                g.fillRect(0, 0, getWidth() - 1 - offset, getHeight() - 1);
            }
	}
	else
	    g.fillRect(0, 0, getWidth()-1, getHeight()-1);
	super.paint(g);