Tkinter - AttributeError: 'str' object has no attribute 'set'

Question

This is the code I have created and am trying to run:

import tkinter as tk


def ok(val):
    print("Value is: ", val)

def say_hi(self):
    print("hi there, everyone!")

class Application(tk.Frame):

    def __init__(self, master=None):
        tk.Frame.__init__(self, master)
        master.title("Hi There")
        master.geometry("400x400")
        self.createWidgets(master)

    def createWidgets(self, master=None):
        var = str()

        self.select = tk.OptionMenu(master, var, "one", "two","three", command=ok).grid(column=1, row=1)

        self.QUIT = tk.Button(master, text="QUIT", fg="red", command=root.destroy).grid(column=2, row=1)
        print ("HI")

root = tk.Tk()
app = Application(master=root)
app.mainloop()

But I am receiving the following error:

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python34\lib\tkinter\__init__.py", line 1533, in __call__
    return self.func(*args)
  File "C:\Python34\lib\tkinter\__init__.py", line 3308, in __call__
    self.__var.set(self.__value)
AttributeError: 'str' object has no attribute 'set'

I tried messing with some of the variables and using different methods to get the menu to work, but nothing seemed to get rid of the error.

Any idea on how to fix the error?

Answer 1

Use a StringVar not a str

  def createWidgets(self, master=None):
        var = tk.StringVar()

A python str has no set method or attribute, a StringVar is specific to tkinter and what you are meant to be using.