java - 改变 nimbus JPopupmenu 行为

Question

我需要有关 JTree 和 JPopupMenu 的 Nimbus 行为的帮助。我正在为 JTree 设置右键菜单。如果我在打开另一个节点的右键菜单后左键单击一个节点，则单击的节点将被选中。但在 nimbus 的外观和感觉中，需要第二次单击才能选择另一个节点。我的代码如下，您可以通过注释 nimbus 部分来尝试使用默认的外观和感觉。

public class JTreeDemo {

    public static void main(String[] args) {

        try {
            for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (Exception e) {
            try {
                UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
            } catch (Exception ex) {
            }
        }

        DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("Root");
        rootNode.add(new DefaultMutableTreeNode("Child1"));
        rootNode.add(new DefaultMutableTreeNode("Child2"));
        rootNode.add(new DefaultMutableTreeNode("Child3"));

        DefaultTreeModel model = new DefaultTreeModel(rootNode);

        JTree tree = new JTree(model);
        tree.addMouseListener(new TreeMouseListener());

        JFrame jf = new JFrame();
        jf.getContentPane().add(new JScrollPane(tree));

        jf.setSize(new Dimension(300, 300));

        jf.setVisible(true);
    }
}

class TreeMouseListener extends MouseAdapter {

    @Override
    public void mouseReleased(MouseEvent e) {
        if(SwingUtilities.isRightMouseButton(e)) {
            JTree tree = (JTree) e.getSource();

            TreePath jClickedPath = tree.getPathForLocation(e.getX(), e.getY());
            tree.setSelectionPath(jClickedPath);

            JPopupMenu menu = new JPopupMenu();
            menu.add(new JMenuItem("menu1"));
            menu.show(tree,  e.getX(), e.getY());
        }
    }
}

Answer 1

如果打印出按下、释放和单击的鼠标事件，您将看到使用默认的 L&F 会得到

// right click
tree: pressed
tree: released
tree: clicked
// click on node
tree: pressed
tree: released
tree: clicked

而使用 Nimbus L&F，您会得到

// right click
tree: pressed
tree: released
tree: clicked
// first click on node, the pressed event is not passed to the listener
tree: released
tree: clicked
// second click on node
tree: pressed
tree: released
tree: clicked

这是 Nimbus 弹出窗口在关闭时消耗事件的期望行为。 (参见错误报告#JDK-6770445中的解释)

您可以在设置 L&F 后更改此行为。

UIManager.setLookAndFeel(info.getClassName());
UIManager.put("PopupMenu.consumeEventOnClose", false);

编辑代码片段，仅更改特定 JTree 的默认行为

// instruct the JTree not to close the popup
tree.putClientProperty("doNotCancelPopup",
    new JComboBox().getClientProperty("doNotCancelPopup"));

// create the popup menu not inside the listener
JPopupMenu popup = new JPopupMenu();
popup.add(new JMenuItem("menu1"));

// add the listener to the JTree
MouseListener popupListener = new PopupListener(popup);
tree.addMouseListener(popupListener);

以编程方式显示和隐藏弹出窗口

static class PopupListener extends MouseAdapter {

    JPopupMenu popup;

    PopupListener(JPopupMenu popupMenu) {
        popup = popupMenu;
    }

    @Override
    public void mousePressed(MouseEvent e) {
        togglePopup(e);
    }

    @Override
    public void mouseReleased(MouseEvent e) {
        togglePopup(e);
    }

    private void togglePopup(MouseEvent e) {
        if (e.isPopupTrigger()) {
            popup.show(e.getComponent(), e.getX(), e.getY());
        } else if (popup.isVisible()) {
            popup.setVisible(false);
        }
    }
}