SWT制作下拉式toolbar菜單按鈕的代碼片段

SWT制作下拉式toolbar菜單按鈕的代碼片段:final ToolItem dropdown = new ToolItem(bar, SWT.DROP_DOWN);dropdown.setText("Drop-down");//一個popoupMenufinal Menu menu = new Menu(shell, SWT.POP_UP);MenuItem choice = new MenuItem(menu, SWT.PUSH);choice.setText("Choices");dropdown.addListener(SWT.Selection, new Listener() { public void handleEvent(Event event) { if (event.detail == SWT.ARROW) { Rectangle rect = dropdown.getBounds(); Point pt = new Point(rect.x, rect.y + rect.height); pt = bar.toDisplay(pt); menu.setLocation(pt.x, pt.y); menu.setVisible(true); } }});