想要将鼠标移动到JTree列出的元素上。

I want to change the cursor to hand cursor on mouse move over JTree component when the cursor is on listed elements only, not for the whole component.

当光标仅在列出的元素上时，我想将光标移到鼠标移动到JTree组件上，而不是整个组件。

The below code is for Jlist Component. I want same for the JTree, but JTree does not have getCellBound(). Is there any other way?

下面的代码用于Jlist组件。对于JTree，我想要相同的，但是JTree没有getCellBound()。还有别的办法吗?

final JList list = new JList(new String[] {"a","b","c"});
list.addMouseMotionListener(new MouseMotionListener() {
@Override
public void mouseMoved(MouseEvent e) {
    final int x = e.getX();
    final int y = e.getY();
    // only display a hand if the cursor is over the items
    final Rectangle cellBounds = list.getCellBounds(0, list.getModel().getSize() - 1);
    if (cellBounds != null && cellBounds.contains(x, y)) {
        list.setCursor(new Cursor(Cursor.HAND_CURSOR));
    } else {
        list.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
    }
}

@Override
public void mouseDragged(MouseEvent e) {
}
});

2 个解决方案

#1

You are looking for something like this, I guess:

你在寻找这样的东西，我想:

import java.awt.Cursor;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

public class TestTreeSelection {

    protected void initUI() {
        final DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
        fillTree(root, 5, "Some tree label");
        final DefaultTreeModel model = new DefaultTreeModel(root);
        final JTree tree = new JTree(model);
        tree.addMouseMotionListener(new MouseAdapter() {
            @Override
            public void mouseMoved(MouseEvent e) {
                boolean inside = false;
                TreePath path = tree.getPathForLocation(e.getX(), e.getY());
                if (path != null) {
                    Rectangle pathBounds = tree.getPathBounds(path);
                    inside = pathBounds.contains(e.getPoint());
                }
                if (inside) {
                    tree.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
                } else {
                    tree.setCursor(Cursor.getDefaultCursor());
                }
            }
        });
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new JScrollPane(tree));
        f.setSize(400, 600);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private void fillTree(DefaultMutableTreeNode parent, int level, String label) {
        for (int i = 0; i < 5; i++) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(label + " " + i);
            parent.add(node);
            if (level > 0) {
                fillTree(node, level - 1, label);
            }
        }
    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new TestTreeSelection().initUI();
            }
        });
    }

}

#2

This code works:

这段代码:

        tree_object.addMouseMotionListener(new MouseMotionListener() {

                @Override
                public void mouseDragged(MouseEvent e) {

                }

                @Override
                public void mouseMoved(MouseEvent e) {
                    TreePath tp = ((JTree)e.getSource()).getPathForLocation(e.getX(), e.getY());

                    if(tp != null)
                    {
                        ((JTree)e.getSource()).setCursor(new Cursor(Cursor.HAND_CURSOR));
                    }
                    else
                    {
                        ((JTree)e.getSource()).setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
                    }
                }
         });