python tkinter entry command can't convert to int

Question

Trying to get used to the tkinter gui but I'm running into a problem with setting up an input box. I wanted to make a simple number guessing program using Entry to input an integer and a button to submit the guess. I'm getting an str to int conversion error when I use int(GuessBox.get()) and I'm not sure what to do.

ValueError: invalid literal for int() with base 10: ''

from tkinter import *
import random

def makeAGuess():
    guess = int(GuessBox.get())
    print(guess)

    if guess == Answer:
        print("you got it!")
        return False
    elif guess > Answer:
        print("Too High, try again")
        return True
    else :
        print("Too low, try again")
        return True

Answer = random.randint(1, 100)


main = Tk()
label = Label(main, text = "Guess a number")
label.pack()
GuessBox = Entry(master = main)
GuessBox.pack()
submitGuess = Button(master = main, text = "Submit Guess", command = makeAGuess())
submitGuess.pack()
main.mainloop()

Answer 1

You need to pass the function as an object, don't call it.

submitGuess = Button( master = main, text = "Submit Guess", command = makeAGuess )

Otherwise makeAGuess is called when the Button is created, but not passed any arguments. With this change your code works perfectly for me.