Question

I am making a simulator with a JTree updating frequently. The nodes in the tree are all JProgressBars.

I’m calling tree.treeModel.insertNodeInto(,,) and treeModel.reload() to update the tree. the problem is that it instantly updates itself without waiting for a repaint() call. This causes the tree to flash. I have tried setting setDoubleBuffered(true) for the nodes, the tree, and the containers it is in, but nothing changes.

Here’s my code: (The class File extends DefaultMutableTreeNode)

public class FileTree extends JTree {

    DefaultTreeModel myTreeModel;

    FileTree(File root) {
        super(root);
        myTreeModel = (DefaultTreeModel) this.getModel();
        this.treeModel = myTreeModel;
        this.setCellRenderer(new ProgressBarCellRenderer());
        this.setEditable(true);
    }

    public void update(File file, File parent) {
        myTreeModel.insertNodeInto(file, parent, parent.getChildCount());
        myTreeModel.reload();
    }

    class ProgressBarCellRenderer extends DefaultTreeCellRenderer {
        public Component getTreeCellRendererComponent(JTree tree, Object value,
                boolean selected, boolean expanded, boolean leaf, int row, boolean hasFocus) {
            File file = (File) value;
            JProgressBar progressBar;
            progressBar = new JProgressBar(0, file.length);
            progressBar.setValue(file.completed);
            progressBar.setPreferredSize(new Dimension((int)(Math.log(file.size)*50),10));
            return progressBar;
        }
    }

}

Answer 1

I fixed it. I just changed

myTreeModel.insertNodeInto(file, parent, parent.getChildCount());

to

parent.add(file);

I don’t know why it works now. But it does. Any comments are appreciated!