Why do I get "AttributeError: NoneType object has no attribute" using Tkinter? Where did the None value come from?
python, tkinter, user-interface
Solution
The `grid`, `pack` and `place` functions of the `Entry` object and of all other widgets returns `None`. In python when you do `a().b()`, the result of the expression is whatever `b()` returns, therefore `Entry(...).grid(...)` will return `None`.
You should split that on to two lines like this:
entryBox = Entry(root, width=60)
entryBox.grid(row=2, column=1, sticky=W)
That way you get your `Entry` reference stored in `entryBox` and it's laid out like you expect. This has a bonus side effect of making your layout easier to understand and maintain if you collect all of your `grid` and/or `pack` statements in blocks.
Problem
I've created this simple GUI: ``` from tkinter import * root = Tk() def grabText(event): print(entryBox.get()) entryBox = Entry(root, width=60).grid(row=2, column=1, sticky=W) grabBtn = Button(root, text="Grab") grabBtn.grid(row=8, column=1) grabBtn.bind('<Button-1>', grabText) root.mainloop() ``` When I click on the `Grab` button, an error occurs: ``` C:\Python> python.exe myFiles\testBed.py Exception in Tkinter callback Traceback (most recent call last): File "C:\Python\lib\lib-tk\Tkinter.py", line 1403, in __call__ return self.func(*args) File "myFiles\testBed.py", line 10, in grabText if entryBox.get().strip()=="": AttributeError: 'NoneType' object has no attribute 'get' ``` Why is `entryBox` set to `None`? See also Why do I get AttributeError: 'NoneType' object has no attribute 'something'? for the general case.