如何在Jtree中刷新XML

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 :

我在这里阅读,但是如果xml文件改变了jtree没有重新加载/刷新如何创建刷新/重载Jtree的函数我尝试编写代码:

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

但我得到了错误:java.lang.NullPointerException

3 个解决方案

#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:

我在getJPopupForExplorerTree()中添加了一个新的Action来弹出。你可能想要从XMLTree构造函数中重新考虑xmlFile;我在下面为了方便而硬编码:

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);
        }
    }
});

#2

this is most complex code, probably

这可能是最复杂的代码
read tutorial about JTables DefaultTableModel (good described concept and logics for DefaultXxxModel is similair / the same)

阅读关于JTables DefaultTableModel的教程(对于DefaultXxxModel,描述的概念和逻辑是类似的/相同的)
read tutorial about JTree

阅读关于JTree的教程
read tutorial about Concurency in Swing,

阅读有关Swing中Concurency的教程,
especially description about SwingWorker

特别是关于SwingWorker的描述
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,

在你的情况下更好(抱歉)将为DefaultTreeModel创建一个新实例,使用SwingWorker填充数据,将新模型添加到可见的JTree,
by replacing model you'll lost all changes in the current JTree

通过替换模型,您将丢失当前JTree中的所有更改

#3

I dont know the spesific code but you can try this

我不知道特定代码,但你可以试试这个

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();
}};

#1