Calculating totals from entries in GUI-CodePudding

Struggling with making this code work in my GUI. I am overloaded with errors and trying to understand syntactically how I can make this work. I am trying to make an order form that takes the number of cookies a customer wants and computes their total. I know that this certainly has to be some simple thing I'm overlooking.

from tkinter import Button, Entry, Label,Tk
from tkinter.messagebox import showinfo

class CookieOrderForm(Tk):

    def __init__(self,parent=None):
        Tk.__init__(self, parent)
        self.title("Cookie Form")
        self.make_widgets()

    def total(self):
        order = sum(int(e.get()) for e in (self.chipEn, self.oatEn, self.oreoEn))
        txt = ("Your Order Total Is: "   str(order))
        self.new.config(text = txt)
        
        

    def make_widgets(self):
        chip = Label(self, text='Chocolate Chip ($1.00)').grid(row=1, column=0)
        self.chipEn = Entry(self)
        self.chipEn.grid(row=1, column=1, columnspan=4)
        oat = Label(self, text='Oatmeal ($1.50)').grid(row=2, column=0)
        self.oatEn = Entry(self)
        self.oatEn.grid(row=2, column=1, columnspan=4)       
        Button(self,text='Order Total', command=lambda:self.total()).grid(row=4, column=2)
        oreo = Label(self, text='Oreo ($2.00)').grid(row=3, column=0)
        self.oreoEn = Entry(self)
        self.oreoEn.grid(row=3, column=1, columnspan=4)
        self.new = Label(self)
        self.new.grid(row=3, column=1)

CookieOrderForm().mainloop()

I think my main issue is coming from this line here order = sum(int(e.get()) for e in (self.chipEn, self.oatEn, self.oreoEn))

EDIT:::: Error Messages Included

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\17734\AppData\Local\Programs\Python\Python39\lib\tkinter\__init__.py", line 1884, in __call__
    return self.func(*args)
  File "C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\CSC242hw4.py", line 91, in <lambda>
    Button(self,text='Order Total', command=lambda:self.total()).grid(row=4, column=2)
  File "C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\CSC242hw4.py", line 78, in total
    order = sum(int(e.get()) for e in (self.chipEn, self.oatEn, self.oreoEn))
  File "C:\Users\17734\OneDrive\Desktop\fall 2021\csc242\homework\CSC242hw4.py", line 78, in <genexpr>
    order = sum(int(e.get()) for e in (self.chipEn, self.oatEn, self.oreoEn))
ValueError: invalid literal for int() with base 10: ''

CodePudding user response：

You may get this error only if you have empty Entry when you press Button.

Try int("") and you see the same error.

You may get similar error when you put some text (like Hello World) instead number.

You could put sum() in try/except to catch errors.

    def total(self):
        try:
            order = sum(int(e.get()) for e in (self.chipEn, self.oatEn, self.oreoEn))
            txt = ("Your Order Total Is: "   str(order))
        except Exception as ex:
            print('Exception:', ex)
            txt = 'Your have wrong values in Order'

        self.new.config(text = txt)

Eventually you should convert every value separatelly in separated try/catch to see which Entry has wrong value and display message with better information.

CodePudding user response：

This may not be the best solution but it works. Added function to check if your input is a digit, if not it will return 0 if yes it will return int

from tkinter import Button, DoubleVar, Entry, Label, StringVar,Tk
from tkinter.messagebox import showinfo


class CookieOrderForm(Tk):

    def __init__(self,parent=None):
        Tk.__init__(self, parent)
        self.title("Cookie Form")
        self.make_widgets()

    def entryIsDigit(self, number: str) -> int:
        if number.isdigit() == True:
            return int(number)
        return 0

    def total(self):
        order = sum(e for e in (self.entryIsDigit(self.chipEn.get()), self.entryIsDigit(self.oatEn.get()), self.entryIsDigit(self.oreoEn.get())))
        txt = ("Your Order Total Is: "   str(order))
        self.new.config(text = txt)
        
        

    def make_widgets(self):
        chip = Label(self, text='Chocolate Chip ($1.00)').grid(row=1, column=0)
        self.chipEn = Entry(self)
        self.chipEn.grid(row=1, column=1, columnspan=4)
        oat = Label(self, text='Oatmeal ($1.50)').grid(row=2, column=0)
        self.oatEn = Entry(self)
        self.oatEn.grid(row=2, column=1, columnspan=4)       
        Button(self,text='Order Total', command=lambda:self.total()).grid(row=4, column=2)
        oreo = Label(self, text='Oreo ($2.00)').grid(row=3, column=0)
        self.oreoEn = Entry(self)
        self.oreoEn.grid(row=3, column=1, columnspan=4)
        self.new = Label(self)
        self.new.grid(row=3, column=1)

CookieOrderForm().mainloop()```