The steps for this section are: 这一期的步骤是Add a new screen that shows all the checklists.添加一个新的屏幕显示所有的清单。Create a screen that lets users add/edit checklists.创建一个屏幕,用户可以添加/编辑清单。Show the to-do items that belong to a particular checklist when you tap the name of that list.当你点击列表的名称时显示待办项属于一个特定的清单。Save all the checklists to a file and load them in again.保存所有清单文件并再次加载它们。
