从输入字段tkinter存储用户输入

Question

So, I've seen other questions on a similar topic to this, I've struggled to make sense of them so I'm asking this one.

I have this program, the majority of the code is below, It's a basic GUI.

I'm having problems with the entry fields that take the users first name and surname, the block of code associated with this is here:

tk.Label(self, text='First Name: ').pack(side=TOP)
EntryFieldFN = Entry(self)
EntryFieldFN.pack(pady=2, padx=2)

tk.Label(self, text='Surname: ').pack()
EntryFieldSN = Entry(self)
EntryFieldSN.pack(pady=2, padx=2)

FirstName = EntryFieldFN.get()
Surname = EntryFieldSN.get()  

I've been unable to work out how to store the user input from these fields into variables that I can then use later. I wish to use the first name and surname of the user in the FinalWindow() function, which I want to act as a receipt of purchase for the order.

def FinalWindow():
    win = Toplevel()
    LabelRW = Label(win, text='Receipt of Purchase')
    ExitProg = Button(win, text='Exit', command=sys.exit)
    LabelRW.pack()
    ExitProg.pack()
    win.title('Virtual Receipt')

class Till(tk.Frame):
    def __init__(self, master=None, **kw):
        tk.Frame.__init__(self, master=master, **kw)
        self.price_string = tk.StringVar()
        tk.Label(self, text='GUI Program - Till System').pack(side=TOP)
        tk.Label(self, text='First Name: ').pack(side=TOP)

        EntryFieldFN = Entry(self)
        EntryFieldFN.pack(pady=2, padx=2)

        tk.Label(self, text='Surname: ').pack()
        EntryFieldSN = Entry(self)
        EntryFieldSN.pack(pady=2, padx=2)

        FirstName = EntryFieldFN.get()
        Surname = EntryFieldSN.get()

        tk.Label(self, textvariable=self.price_string).pack(side=BOTTOM)
        tk.Label(self, text="Total Price: ").pack(side=BOTTOM)
        self.items = []

    # For each stock item, create an IntVar, a checkbox and keep record of the price/name

        for idx, item in enumerate(stock_items):
            new_item = {}
            new_item['var'] = tk.IntVar()
            new_item['check'] = tk.Checkbutton(self, text=item['name'], variable=new_item['var'], command=self.recalculate)
            new_item['check'].pack()
            new_item['name'] = item['name']
            new_item['price'] = item['price']
            self.items.append(new_item)

        ExitButton = Button(root, text='Exit', command=sys.exit)
        OrderButton = Button(root, text='Order', command=FinalWindow)
        ExitButton.pack(side=BOTTOM, padx=2, pady=2)
        OrderButton.pack(side=BOTTOM, padx=2, pady=2)
        ExitButton.config(height=1, width=8)
        OrderButton.config(height=1, width=8)

# Recalculate is called when ever a checkbox is checked/unchecked

    def recalculate(self):
        total_price = 0

    # Go through each item and if it is selected add its price to the total

        for item in self.items:
            if item['var'].get():
                total_price += item['price']

    # Display out total price

        self.price_string.set('£ {:.2f}'.format(total_price))

if __name__ == '__main__':
    root = tk.Tk()
    Till(root).pack()
    root.mainloop()

I've tried a couple of things so far, none of which have worked, I don't know if it would be a good idea to use global variables for the inputs.

Answer 1

There are at least two ways to solve this problem. Both of them start by having your button call a method which is part of the class:

OrderButton = Button(root, text='Order', command=self.do_order)

You also need to make sure that you keep a reference to the entry widgets, so instead of EntryFieldFN and EntryFieldSN you should use self.EntryFieldFN and self.EntryFieldSN . This is so that you can get access to the widgets from anywhere in the class.

def __init__(self, master=None, **kw):
    ...
    self.EntryFieldFN = Entry(self)
    self.EntryFieldSN = Entry(self)
    ...

Note: this concept applies to all other input widgets (eg: the Checkbuttons). I'm limiting the answer to these two widgets to make the code examples smaller and easier to manage.

With that out of the way, you can do one of two things: your function can get the values and pass it to FinalWindow , or it can pass itself to FinalWindow and let FinalWindow get the values it needs.

Passing the individual values

For the first case, you need to define FinalWindow to take the values as parameters:

def FinalWindow(first, last):
    ...

Next, have do_order get the values and call the function:

def do_order(self):
    first_name = self.EntryFieldFN.get()
    surname = self.EntryFieldSN.get()
    window = FinalWindow(first_name, surname)

Passing the class instance

Instead of passing the values, you can pass the instance of Till to FinalWindow .

First, modify FinalWindow to accept a single parameter, which is a instance of Till . It can then use this instance to get the data it needs.

def FinalWindow(till):
    first_name = till.EntryFieldFN.get()
    surname = till.EntryFieldSN.get()
    ...

Next, modify do_order to simply pass itself to the function:

def do_order(self):
    window = FinalWindow(self)