python - Meaning of "AttributeError: NoneType object has no attribute tk"?

Question

What does the following error message mean?

AttributeError: 'NoneType' object has no attribute 'tk'

Answer 1

I have had this problem but found the solution. This problem arises when you declare the variable before you make an instance of Tk().

For example, this will bring the error

count = IntVar()
....
....
app = Tk()

Solution!! Make the declarations after creating a tkinter application window

app = Tk()
....
count = IntVar()