添加节点时未显示 Jtree！

Question

我在滚动窗格中有一个静态 jtree。现在我正在尝试将子项添加到jtree，它已成功添加。现在，添加的节点在 jtree 中不可见。

尝试1：我尝试过 model.reload()

DefaultTreeModel model = (DefaultTreeModel) (tree.getModel());
TreePath Path = findByName(tree, new String[]{Globals.CONS_UIAPROJECTS});
DefaultMutableTreeNode pnode = (DefaultMutableTreeNode) Path.getLastPathComponent();
model.insertNodeInto(UIAProjectExploreDisplay.nodeProTree, pnode, pnode.getChildCount());
model.reload();

尝试2：我也尝试过tree.setModel()...

DefaultTreeModel model = (DefaultTreeModel) (tree.getModel());
TreePath Path = findByName(tree, new String[]{Globals.CONS_UIAPROJECTS});
DefaultMutableTreeNode pnode = (DefaultMutableTreeNode) Path.getLastPathComponent();
model.insertNodeInto(UIAProjectExploreDisplay.nodeProTree, pnode, pnode.getChildCount());

DefaultTreeModel projectTreeModel = new DefaultTreeModel((DefaultMutabletreeNode) model.getRoot());
tree.setModel(projectTreeModel);

即使如此，新添加的子项也不可见。但它被添加到树中。我通过打印孩子进行了测试。 给我建议一个解决方案。

Answer 1

只需尝试以下行：

model.reload();

检查这个简单的示例。它对我有用，并在 5 秒延迟后显示两个新节点。

/**
 * @param args
 */
public static void main(String[] args) {
    TestTree frame= new TestTree();
    frame.setSize(400, 400);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
    frame.pack();
    MutableTreeNode root = (MutableTreeNode)tree.getModel().getRoot();
    System.out.println("A: "+root.getChildCount());     
    try {
        Thread.sleep(5000);
    }
    catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    root.insert(new DefaultMutableTreeNode("test"), 1);
    ((DefaultMutableTreeNode)root.getChildAt(2)).insert(new DefaultMutableTreeNode("test2"), 1);
    ((DefaultTreeModel)(tree.getModel())).reload();
    System.out.println("B: "+root.getChildCount());
    System.out.println(root.getChildAt(1));
}

Answer 2

我想也许你忘记在 TreeNode 的插入方法中设置新节点的父节点......这是我的代码

public void insert(MyTreeNode newChild, int childIndex) {
    if (!allowsChildren) {
        throw new IllegalStateException("node does not allow children");
    } else if (newChild == null) {
        throw new IllegalArgumentException("new child is null");
    }

        newChild.setParent(this);
        if (children == null) {
            children = new ArrayList<GoodSort>();
        }
        children.add(childIndex,(GoodSort)newChild);
        ((GoodSort)newChild).parent = this;
}