How to refresh XML in Jtree

问题

I read here , but if the xml file changes the jtree does not reload /refreshes
how to create a function for refresh / reload Jtree
I try to write code :

refreshAction = new AbstractAction("Refresh", IconFactory.getIcon("delete", IconFactory.IconSize.SIZE_16X16)) {
public void actionPerformed(ActionEvent e) {
    XMLTree xmlClass = null;
    ((DefaultTreeModel) xmlClass.getModel()).reload(); 
    System.out.println("Refresh");
}};

but i got the error : java.lang.NullPointerException

回答1:

I added a new Action to popup in getJPopupForExplorerTree(). You'll probably want to re-factor xmlFile out of the XMLTree constructor; I've hard coded it for expedience below:

popup.add(new AbstractAction("Reload") {

    public void actionPerformed(ActionEvent e) {
        System.out.println("Reload");
        try {
            root = getRoot("xml.xml");
            setModel(new XMLTreeModel(root));
        } catch (Exception ex) {
            ex.printStackTrace(System.err);
        }
    }
});

回答2:

this is most complex code, probably
read tutorial about JTables DefaultTableModel (good described concept and logics for DefaultXxxModel is similair / the same)
read tutorial about JTree
read tutorial about Concurency in Swing,
especially description about SwingWorker
in your case better (sorry for that) would be create an new instance for DefaultTreeModel, fills data by using SwingWorker, add new model to the visible JTree,
by replacing model you'll lost all changes in the current JTree

回答3:

I dont know the spesific code but you can try this

refreshAction = new AbstractAction("Refresh", IconFactory.getIcon("delete", IconFactory.IconSize.SIZE_16X16)) {
public void actionPerformed(ActionEvent e) {
     DefaultTreeModel myTreeModel = (DefaultTreeModel) xmlClass.getModel();

     myTreeModel.reload();

     revalidate();
     repaint();
}};

来源：https://stackoverflow.com/questions/11841117/how-to-refresh-xml-in-jtree

标签

java

xml

swing

reload

jtree