右键单击 Java JTree 的上下文菜单？

contextmenu java jtree

2022-09-01 12:39:00

我正在尝试在Java JTree中实现弹出菜单。我已经对DefaultTreeCellRenderer（更改节点外观）和DefaultTreeCellEditor（创建要附加事件侦听器的组件，因为显然DefaultTreeCellRenderer.getTreeCellRendererComponent（）返回的组件无法做到这一点？）。我真的不想“编辑”节点，只是在节点被右键单击时弹出一个菜单，但这是我现在能想到的唯一方法......

以下是我到目前为止拥有的代码 - 我只是试图弄清楚如何捕获MouseEvents。它有点管用，但很糟糕。有什么更好的方法来完成我在这里想要做的事情？

private class My_TreeCellRenderer extends DefaultTreeCellRenderer { 
    My_TreeCellRenderer() {
        super ();
    }   

    public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected, boolean expanded, boolean leaf, int row, boolean hasFocus) {
        super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, hasFocus);

        // set label text and tool tips
        setText(((My_Object)value).getTreeLabel());
        setToolTipText(((My_Object)value).getTreeToolTip());

        return this;
    }
}

private class My_TreeCellEditor extends DefaultTreeCellEditor { 
    private MouseAdapter ma;

    My_TreeCellEditor(JTree tree, DefaultTreeCellRenderer renderer) {
        super (tree, renderer);
        ma = new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                if (e.isPopupTrigger()) {
                    System.out.println("My Popup");
                }
            }
            public void mouseReleased(MouseEvent e) {
                if (e.isPopupTrigger()) {
                    System.out.println("My Popup");
                }
            }
        };
    }

    public Component getTreeCellEditorComponent(JTree tree, Object value, boolean selected, boolean expanded, boolean leaf, int row) {
        String src_filename = null;

        // return non-editing component
        Component c = renderer.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, true);

        // add mouse listener if it's not listening already
        MouseListener mouseListeners[] = c.getMouseListeners();
        int i;
        for (i=0; i < mouseListeners.length && mouseListeners[i] != ma; i++);
        if (i >= mouseListeners.length)
            c.addMouseListener(ma);

        return c;
    }

    protected boolean canEditImmediately(EventObject event) {
        if (event instanceof MouseEvent && ((MouseEvent)event).getClickCount() == 1)
            return true;
        else
            return false;
    }
}

答案 1

此任务简单易行，以下是您所需要的：

//create a class which implements the MouseListener interface and
//implement the following in your overridden mouseClicked method

@Override
public void mouseClicked(MouseEvent e) {

    if (SwingUtilities.isRightMouseButton(e)) {

        int row = tree.getClosestRowForLocation(e.getX(), e.getY());
        tree.setSelectionRow(row);
        popupMenu.show(e.getComponent(), e.getX(), e.getY());
    }
}

然后，您可以将此自定义侦听器添加到所需的树中。

答案 2

直接从 JTree API 中取出

 // If you are interested in detecting either double-click events or when a user clicks on a node, regardless of whether or not it was selected, we recommend you do the following:

 final JTree tree = ...;

 MouseListener ml = new MouseAdapter() {
     public void mousePressed(MouseEvent e) {
         int selRow = tree.getRowForLocation(e.getX(), e.getY());
         TreePath selPath = tree.getPathForLocation(e.getX(), e.getY());
         if(selRow != -1) {
             if(e.getClickCount() == 1) {
                 mySingleClick(selRow, selPath);
             }
             else if(e.getClickCount() == 2) {
                 myDoubleClick(selRow, selPath);
             }
         }
     }
 };
 tree.addMouseListener(ml);

当然，您需要对其进行一些修改以进行右键单击而不是左键单击