Strikethrough a node in a JTree

Question

Strikethrough a node in a JTree

272 views Asked by scoob27 At 07 August 2015 at 07:00

In my project i have a Jtree with custom node (which extends DefaultMutableTreeNode). Each node is associated with a boolean value. When the boolean is False i woul like to strike the texte of my node. So for example :

node 1
- node1.1
- ~~node1.2~~
node 2
- node2.1
- ...

I tried to create a new Font but i don't find any properties to strike the text and i only managed to add my custom font to the whole tree and not node by node.

I think that i should use the TreeRenderer but i can't find any method to help me strike the node.

Does someone have an idea on i can do it ?

Original Q&A

There are 2 answers

StanislavL On 07 August 2015 at 07:16

The simplest way would be to define a renderer (extending DefaultTreeCellRenderer) and call setText() passing html string like this "<html><u>node1.2</u></html>" as value for the strikethrough.

**Dakshinamurthy Karra** · Accepted Answer · 2015-08-07 07:15:30

Check out the example below. For keeping it simple, I am just striking through the selected node. You need to, of course, use your own check on the value.

package snippet;

import java.awt.Component;
import java.awt.Font;
import java.awt.font.TextAttribute;
import java.util.Map;

import javax.swing.JFrame;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.tree.DefaultTreeCellRenderer;

public class JTreeTest extends JFrame {
    private final class StrikeoutCellRenderer extends DefaultTreeCellRenderer {
        private static final long serialVersionUID = 1L;

        @Override public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded,
                boolean leaf, int row, boolean hasFocus) {
            Component c = super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
            Font font = c.getFont();
            Map attributes = font.getAttributes();
            if(sel)
                attributes.put(TextAttribute.STRIKETHROUGH, TextAttribute.STRIKETHROUGH_ON);
            else
                attributes.remove(TextAttribute.STRIKETHROUGH);
            Font newFont = new Font(attributes);
            c.setFont(newFont);
            return c;
        }

    }

    private static final long serialVersionUID = 1L;

    public JTreeTest() {
        super(JTreeTest.class.getName());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        initComponents();
    }

    private void initComponents() {
        JTree tree = new JTree();
        tree.setCellRenderer(new StrikeoutCellRenderer());
        add(tree);
        pack();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override public void run() {
                JTreeTest t = new JTreeTest();
                t.setVisible(true);
            }
        });
    }
}

Note that even if the node doesn't need a strike through, you need to reset the attribute, since a single component is used for painting all the nodes.

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Strikethrough a node in a JTree

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