Tkinter - Entry .get() Function

Question

class FCMenu:
def __init__(self,master):
    frame=Frame(master)
    frame.pack()
    Label(frame, text="What is the number?").grid(row=0)
    self.num = IntVar()
    self.entry = Entry(frame,textvariable=self.num).grid(row=1)
    button = Button(frame, text="Factorize", command=self.calc).grid(row=2)
    self.resultvar = StringVar()
    Label(frame, textvariable=self.resultvar).grid(row=3)

def calc(self):
    e = int(self.entry.get())
    print(e,self.num.get())
    ...

I am trying to create a Python GUI with tkinter, as shown above. However, every time I call .get() on the entry or the textvariable, it fails. With the entry itself, it explains that there is no .get() function for NoneType. If I remove that and use only self.num.get(), it prints 0 or 0.0, depending on whether or not I turn it to an integer. If I turn self.num to a StringVar, it prints nothing at all. Simply, I cannot find a way to obtain the input that I want to retrieve.

score 1 · Accepted Answer · answered Dec 31 '15 at 00:16

Made a simplified version of your code, and it prints correctly as the Entry widget is changed. Could be error elsewhere in your code? Or wrong indentation? Here is the code I tested with (this is 2.7 code, but worked with a 3.5 version of the code also):

import Tkinter as tk

class FCMenu:
    def __init__(self, master):
        frame = tk.Frame(master)

        self.num = tk.IntVar()
        self.entry = tk.Entry(frame, textvariable=self.num)
        self.button = tk.Button(frame, text='Calc', command=self.calc)

        frame.pack()
        self.entry.pack()
        self.button.pack()

    def calc(self):
        print(self.num.get(), self.entry.get())

root = tk.Tk()
frame = FCMenu(root)
root.mainloop()

It prints from both self.num.get() and self.entry.get(). The first is an Int and the second as String it seems.

Thank you very much! It seems that the grid was the issue, as your .pack() solution works perfectly. — StardustGogeta, Dec 31 '15 at 00:33
Good that you got it to work. I think mixing pack and grid might cause problems, now that you mention it. Personally I have used only Grid for the GUIs I have made, never tried mixing them. Pack I have only used for quick tests. — oystein-hr, Dec 31 '15 at 04:04

Tkinter - Entry .get() Function

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