Dynamically changing the icon of specific nodes in JTree
I've seen many examples for changing the icon of nodes during tree instantiation, but I would like to dynamically change the icon of a single node again later. So, in my main code, I add my own renderer to my tree:
// Icon I want to set nodes to later
ImageIcon checkIcon = new ImageIcon("check.jpg");
// Creates tree with my nodes
JTree tree = new JTree(nodes.top);
// Create custom renderer
Scenario1Renderer renderer = new Scenario1Renderer();
// Set to single tree selection
tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
// Set tree to my custom renderer
//renderer.setRendererIcon(greenIcon);
tree.setCellRenderer(renderer);
My code in the renderer
public class Scenario1Renderer extends DefaultTreeCellRenderer {
ImageIcon rendererIcon;
public void setRendererIcon(ImageIcon myIcon){
this.rendererIcon = myIcon;
};
public Component getTreeCellRendererComponent(
JTree tree,
Object value,
boolean sel,
boolean expanded,
boolean leaf,
int row,
boolean hasFocus)
{
Component ret = super.getTreeCellRendererComponent(tree, value,
selected, expanded, leaf, row, hasFocus);
//setIcon( rendererIcon ) ;
return ret;
}
So, obviously, if I set my rendererIcon, it will draw all my nodes with the icon I pass during tree instantiation. Instead, I want to use some method that can later set the icon of an individual node when my program is running.
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1 answer
You may have different icons that you can set according to different conditions. Below is a simple example that changes the icon of the selected node:
import java.awt.Component;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
public class TestTree {
private static void createAndShowUI() {
JFrame frame = new JFrame();
final JTree tree = new JTree(buildDemoModel());
tree.setCellRenderer(new DefaultTreeCellRenderer() {
private Icon loadIcon = UIManager.getIcon("OptionPane.errorIcon");
private Icon saveIcon = UIManager.getIcon("OptionPane.informationIcon");
@Override
public Component getTreeCellRendererComponent(JTree tree,
Object value, boolean selected, boolean expanded,
boolean isLeaf, int row, boolean focused) {
Component c = super.getTreeCellRendererComponent(tree, value,
selected, expanded, isLeaf, row, focused);
if (selected)
setIcon(loadIcon);
else
setIcon(saveIcon);
return c;
}
});
tree.setVisibleRowCount(10);
frame.add(new JScrollPane(tree));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.pack();
frame.setVisible(true);
}
private static DefaultTreeModel buildDemoModel() {
DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
root.add(new DefaultMutableTreeNode("A"));
root.add(new DefaultMutableTreeNode("B"));
root.add(new DefaultMutableTreeNode("C"));
return new DefaultTreeModel(root);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
createAndShowUI();
}
});
}
}
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