Question

我创建了一个JTree，其中一些节点是自定义的，以显示它们是可扩展的，尽管它们还没有任何子节点。我已经按照this thread来实现它。

为什么呢？我想动态加载树，所以当树扩展时，我从服务器检索更多信息并在树上显示。

我遇到的问题是，当我展开其中一个节点时，它会被选中，这不是默认节点的默认行为（您可以在不更改树选择的情况下展开它们）。

如何解决此问题以防止此节点在扩展时被选中？

Answer 1

我没有遇到以下代码的问题。如果没有看到你的代码，你必须做一些我们无法猜到的事情。尝试使用下面的代码并修改它以重现您遇到的问题。通过这样做，您很有可能会发现您正在做的不同以及为什么会出现这种行为（另请参阅SSCCE）。

代码取自here

import java.awt.BorderLayout;
import java.awt.Container;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeNode;

public class DynamicTree extends JFrame {

    public class OutlineNode extends DefaultMutableTreeNode {
        private boolean areChildrenDefined = false;
        private int outlineNum;
        private int numChildren;

        public OutlineNode(int outlineNum, int numChildren) {
            this.outlineNum = outlineNum;
            this.numChildren = numChildren;
        }

        @Override
        public boolean isLeaf() {
            return false;
        }

        @Override
        public int getChildCount() {
            if (!areChildrenDefined) {
                defineChildNodes();
            }
            return super.getChildCount();
        }

        private void defineChildNodes() {
            // You must set the flag before defining children if you
            // use "add" for the new children. Otherwise you get an infinite
            // recursive loop, since add results in a call to getChildCount.
            // However, you could use "insert" in such a case.
            areChildrenDefined = true;
            for (int i = 0; i < numChildren; i++) {
                add(new OutlineNode(i + 1, numChildren));
            }
        }

        @Override
        public String toString() {
            TreeNode parent = getParent();
            if (parent == null) {
                return String.valueOf(outlineNum);
            } else {
                return parent.toString() + "." + outlineNum;
            }
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new DynamicTree(5);
            }
        });
    }

    public DynamicTree(int n) {
        super("Creating a Dynamic JTree");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (UnsupportedLookAndFeelException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Container content = getContentPane();
        JTree tree = new JTree(new OutlineNode(1, n));
        content.add(new JScrollPane(tree), BorderLayout.CENTER);
        setSize(300, 475);
        setVisible(true);
    }
}

阻止JTree中节点扩展的节点选择

1 个答案: