javax.swing.JMenu#getMenuComponent ( )源码实例Demo

/**
 * Convenience method that recursively enables every JMenu and JMenuItem inside
 * "menu".
 *
 * @param menu - the menu to start the recursive search
 */
public static void enableAll(JMenu menu) {
    for (int i = 0; i < menu.getMenuComponentCount(); i++) {
        Component x = menu.getMenuComponent(i);
        if (x instanceof JMenuItem)
            ((JMenuItem) x).setEnabled(true);
        else if (x instanceof JMenu)
            enableAll((JMenu) x);
    }
}
 

private static void setMnemonics(final JMenuItem item) {
    if (item instanceof JMenu) {
        final JMenu menu = (JMenu) item;
        final int c = menu.getMenuComponentCount();
        final ArrayList<JMenuItem> list = new ArrayList<JMenuItem>(c);
        for (int i = 0; i < c; i++) {
            final Component co = menu.getMenuComponent(i);
            if (co instanceof JMenuItem)
                list.add((JMenuItem) co);

        }
        if (list.size() > 0)
            setMnemonics(list);
    }
}
 

/**
 * Remove any potential orphan separator at the end of the menu.
 *
 * @param menu the menu to purge
 */
public static void trimSeparator (JMenu menu)
{
    int count = menu.getMenuComponentCount();

    if ((count > 0) && menu.getMenuComponent(count - 1) instanceof JSeparator) {
        menu.remove(count - 1);
    }
}
 

/**
 * Take any given memu object and turn on scrollbars if it contains more than 20 items.
 * Then, cycle through all submenus recursively.
 * 
 * @param menu
 */
public static void createScrollBarsOnMenus(JMenu menu) {
    if (menu.getMenuComponentCount() > 20) {
        MenuScroller.setScrollerFor(menu, 20);
    }
    for (int i = 0; i < menu.getMenuComponentCount(); i++) {
        if (menu.getMenuComponent(i) instanceof JMenu) {
            MenuScroller.createScrollBarsOnMenus(((JMenu)menu.getMenuComponent(i)));
        }
    }
}
 

/**
 * Add a separator to a menu if useful.
 * 
 * @param menu Menu.
 * @return Number of items added.
 */
public int addSeparator(JMenu menu) {
  if ((menu == null) || (menu.getMenuComponentCount() == 0)) {
    return 0;
  }
  Component item = menu.getMenuComponent(menu.getMenuComponentCount() - 1);
  if (!(item instanceof JMenuItem)) {
    return 0;
  }
  menu.add(new JSeparator());
  return 1;
}
 

@Override
public void finishMenu(String path) {
    path = mapping(path);
    if (path.equals("_") || path.startsWith("_/")) {
        return;
    }
    if (!menuElements.containsKey(path)) {
        throw new IllegalArgumentException("Invalid menu: " + path);
    }
    if (path.startsWith("/file/recent")) {
        return;
    }
    MenuElement me = menuElements.get(path);
    if (me instanceof JMenu) {
        JMenu jm = (JMenu) me;
        if (jm.getMenuComponentCount() == 1) {
            String parentPath = path.contains("/") ? path.substring(0, path.lastIndexOf('/')) : "";
            MenuElement parMe = menuElements.get(parentPath);
            JMenuItem mi = (JMenuItem) jm.getMenuComponent(0);
            jm.remove(mi);
            if (parMe instanceof JMenu) {
                JMenu parMenu = (JMenu) parMe;
                parMenu.remove(jm);
                parMenu.add(mi);
            } else if (parMe instanceof JMenuBar) {
                JMenuBar parMenuBar = (JMenuBar) parMe;
                parMenuBar.remove(jm);
                parMenuBar.add(mi);
            }
        }
    }
}
 

/**
 * Remove any potential orphan separator at the end of the menu.
 *
 * @param menu the menu to purge
 */
public static void trimSeparator (JMenu menu)
{
    int count = menu.getMenuComponentCount();

    if ((count > 0)
        && menu.getMenuComponent(count - 1) instanceof JSeparator) {
        menu.remove(count - 1);
    }
}
 

/**
 * Sets the menu font.
 *
 * @param m a menu
 * @param font the font
 */
private static void setMenuFont(JMenu m, Font font) {
  m.setFont(font);
  for(int i = 0; i<m.getMenuComponentCount(); i++) {
    m.getMenuComponent(i).setFont(font);
    if(m.getMenuComponent(i) instanceof JMenu) {
      setMenuFont((JMenu) m.getMenuComponent(i), font);
    }
  }
}