Java基于swing实现的弹球游戏代码(5)

                                }
                                if (command.equals("困难") && list.size() == 0) {
                                        creatBall(40, 2);
                                }
                                if (command.equals("游戏说明")) {
                                        JOptionPane.showMessageDialog(null,
                                                        "移动鼠标，用挡板接球，如果接不住，就算输了……\n游戏可以选择难度，包括简单、中等、困难");
                                }
                                if (command.equals("关于")) {
                                        JOptionPane
     .showMessageDialog(null,
      "这是一个用Java编写的小游戏……\n制作人：沈冠军\n时间：2010年8月\n版权所有,翻版必究！");
                                }
                        }
                };
                // 添加动作监听器
                star_item.addActionListener(listener);
                exit_item.addActionListener(listener);
                easy_item.addActionListener(listener);
                middle_item.addActionListener(listener);
                hard_item.addActionListener(listener);
                help_item.addActionListener(listener);
                about_item.addActionListener(listener);

                // 将菜单选项对象添加到菜单对象上
                menu_menu.add(star_item);
                menu_menu.add(exit_item);
                help_menu.add(help_item);
                help_menu.add(about_item);
                // 将菜单对象添加到菜单条上
                bar.add(menu_menu);
                bar.add(difficulty_menu);
                bar.add(help_menu);
                // 返回菜单条对象
                return bar;
        }