How to refresh JTree UI

Question

I have a JTree that shows files and folders of a directory. Also there is a button that disables some of the nodes in the JTree (using DefaultTreeCellRenderer).

The item gets disabled when I press the button, but JTree does not show it as a disabled item. Until I click somewhere, or in on if the items of the tree, then it also shows the disabled look of the item.

I know there is a reload() method for DefaultTreeModel. But I use a customised model. So this method doesnt work. Here is the model that I use to list files and folders: FileSystemModel

And this is my code:

public class FileViewer {
    JFrame frame;
    JPanel panel;
    JTree tree;
    File root;
    public ArrayList<String> disabledNodes = new ArrayList<String>();
    public FileViewer(){
        frame = new JFrame("File Viewer");
        panel = new JPanel(new BorderLayout());


        root = new File("D:\\Documents\\A X");
        FileSystemModel model = new FileSystemModel(root);


        tree = new JTree();
        tree.setModel(model);
        panel.add(tree, BorderLayout.CENTER);


        JButton press = new JButton("Press");
        panel.add(press, BorderLayout.SOUTH);
        press.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e){
                disabledNodes.add("folder1");
            }
        });


        tree.setCellRenderer(new CustomDefaultTreeCellRenderer());

        frame.add(panel);
        frame.setSize(600, 600);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        new FileViewer();
    }
    class CustomDefaultTreeCellRenderer extends DefaultTreeCellRenderer{

        @Override
        public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus){

            super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
            File node = (File)value;
            String name = node.getName();

            for(String element : disabledNodes){

                if(name.equals(element)){
                    this.setEnabled(false);
                }
            }

            return this;

        }
    }
}

However, in the ActionListener of the button, I added tree.updateUI(); and it perfectly worked. But somehow I have heard updating UI is a bad practice since it will make other problems later. So is using updateUI correct here? or there is a better way to make the UI updated with clicks and user interactions?

Note, I will not add or remove any file from the tree, I just have to enable/disable nodes. UPDATE: I just notice there is a repaint() option that does similar function for me. But still, Is it the right way of refreshing the JTree?

Answer 1

repaint() is the correct API to use in this situation.