我正在研究这个问题：编写一个 Python 程序，允许用户从餐厅的菜单中订购项目。
GUI 应允许客户输入他或她的姓名和电话号码。
系统必须生成一个随机数来指示订单号。
应允许顾客选择：(1) 沙拉菜单中的任何项目，(2) 任何一种开胃菜，(3) 任何一种主菜
当用户单击订单按钮时，程序应显示客户详细信息（姓名和电话号码）以及基于他或她的选择的订单详细信息。
应该有一个字段将显示订单的总金额。
6. 交易成功后，必须将订单号和订单总金额等信息写入文本文件。注意不要在文本文件中覆盖以前的信息。
我的程序运行良好，但我不知道如何执行第 6 项。将订单号广告总额写入文本文件而不覆盖。
这是我的代码：#创建一个菜单程序
import random
from Tkinter import *
class App(Frame):
#GUI application
def __init__(self,master):
Frame.__init__(self,master)
self.grid()
self.create_widgets()
def create_widgets(self):
#Label to welcome the user
Label(self, text="Welcome to Costa's restaurant menu"
).grid(row=0, column=0, sticky=W)
#Label to request the name of the customer
Label(self, text="Customer Name: "
).grid(row=1, column=0, sticky=W)
self.ent_cust = Entry(self)
self.ent_cust.grid(row=1, column=1, sticky=W)
#Label to request the telephone number:
Label(self, text="Telephone number: "
).grid(row=1, column=2, sticky=W)
self.ent_tel = Entry(self)
self.ent_tel.grid(row=1, column=3, sticky=W)
#Label to generate a random order number
rnd = (int(random.randrange(50)) + 1)
Label(self, text=("Your order number " + str(rnd))).grid(row=0, column=2, sticky=W)
n = 4
#MENU items to choose from
#the salads
Label(self, text="Select any items from the salad menu: @R30").grid(row=n, column=0, sticky=W)
self.has_greensalad = BooleanVar()
# the green salad
Checkbutton(self, text="Special mixed green salad"
, variable=self.has_greensalad).grid(row=(n + 1), column=0, sticky=W)
#the blue cheese salad
self.has_bluecheese = BooleanVar()
Checkbutton(self, text="Blue cheese salad"
, variable=self.has_bluecheese).grid(row=(n + 1), column=1, sticky=W)
#the greek salad
self.has_greek = BooleanVar()
Checkbutton(self, text="Greek salad"
, variable=self.has_greek).grid(row=(n + 1), column=2, sticky=W)
#the starters
z = (n + 2)
Label(self, text="Select any one of the starter menu: @60:"
).grid(row=z, column=0, sticky=W)
#the oysters
self.startermenu = StringVar()
Radiobutton(self, text="6 oysters",
variable=self.startermenu, value="6 oysters"
).grid(row=(z + 1), column=0, sticky=W)
#the prawns
Radiobutton(self, text="Prawns",
variable=self.startermenu, value="Prawns"
).grid(row=(z + 1), column=1, sticky=W)
#chicken wings
Radiobutton(self, text="Chicken wings",
variable=self.startermenu, value="Chicken wings"
).grid(row=(z + 1), column=2, sticky=W)
#main course
x = (z + 3)
Label(self, text="Select any one of the main menu @ R150"
).grid(row=x, column=0, sticky=W)
self.maincourse = StringVar()
main_courses = ["Hamburger with chips", "Lasagne","Pasta Carbonara","Risotto alla milanese"]
column = 0
for main in main_courses:
Radiobutton(self,
text = main,
variable=self.maincourse,
value = main
).grid(row=(x + 1), column=column, sticky=W)
column += 1
q = (x + 5)
Button(self, text='Place the Order', command=self.determine_order).grid(row=q, column=1, sticky=W)
self.txt_order = Text(self, width=75, height=10, wrap=WORD)
self.txt_order.grid(row=(q + 1), column=0, columnspan=4)
Label(self, text="Total: R",
).grid(row=(q + 11)
, column=0, sticky=W)
self.txt_total = Text(self, width=8, height=1, wrap=NONE)
self.txt_total.grid(row=(q + 11), column=0)
def determine_order(self):
""" Fill text box with order based on user input. """
totalprice = 0
salads = 30
starters = 60
mainmenu = 150
name = self.ent_cust.get()
tel = self.ent_tel.get()
salads = ""
if self.has_greensalad.get():
salads += "Special mixed Green Salad\n"
totalprice = (totalprice + starters)
if self.has_bluecheese.get():
salads += "Blue cheese salad\n"
totalprice = (totalprice + starters)
if self.has_greek.get():
salads += "Greek Salad\n"
totalprice = (totalprice + starters)
if (salads == ""):
salads = "No salads ordered\n"
totalprice = (totalprice + 0)
startermenu = self.startermenu.get()
if (len(startermenu) == 0):
startermenu = "You didn't order a starter"
else:
totalprice = (totalprice + starters)
maincourse = self.maincourse.get()
if (len(maincourse) == 0):
maincourse = "You didn't order a main course"
else:
totalprice = (totalprice + mainmenu)
order = ((((((((name + " (") + tel) + ") ordered from the salad menu:\n") + salads) + "\nFrom the starters menu:\n ") + startermenu) + "\n\nFrom the main menu:\n") + maincourse)
self.txt_order.delete(0.0, END)
self.txt_order.insert(0.0, order)
self.txt_total.delete(0.0, END)
self.txt_total.insert(0.0, float(totalprice))
def main():
root = Tk()
root.title("Costa's Restaurant Menu")
app = App(root)
root.mainloop()
main()