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Tkinter Class and Button use

I am having trouble finding a way to accomplish what I want using buttons in tkinter. I am programming a multi-frame tkinter app, for myself, and each frame is a class, each class has buttons that I place on the screen in the __init__ method. I am having trouble trying to link the buttons and the command functions together.
Example:
class frameHome:
def __init__(self,parent, controller)
self.frame=tk.Frame(parent)
self.buttonOne=tk.Button(self.frame,text="Click Me") # I want to add the command here
self.buttonOne.pack()
def buttonOneClick():
print("You clicked me")
When I add the command in the tk.Button() call it says buttonOneClick not defined. One video I watched said to add the function at the top of the code. I would like to keep the function as a method of the class for organization, as well as keep init at the top of the class and was wondering if there is a way to create a reference to the function so I can have it as a method after the the init method and be able to call it in the init method, because I would like the init method to create the gui and link all widget commands for that class/frame in it.
Thank you for any time and help that you can offer

in your command did you write the command as command=buttonOneClick()? if that's the case then you should replace it with self.buttonOneClick()

The answer I needed was that I forgot the self param in the buttonOneClick(self, msg) method.

Python Tkinter - How do I change variables from outside the main window class?

Now i understand the concept of instance variables and classes, I've never had a problem with them before and I use them frequently. However when I make my MainWindow class, everything is peachy until i try accessing instance variables.
http://pastebin.com/tDs5EJhi is the full code, but at this point it's just placing labels and frames and whatnot, no actual logic is going on. The window looks fine and nothing bad happens.
My question comes to be when I try changing things inside of the window externally. I figured I could just make an instance of the class and change variables from there (namely instancevariable.ImageCanvas.itemconfig()) like i can normally, but Tkinter isn't being nice about it and I think it's a result of Tkinter's mainloop().
Here's the tidbit of my class MainWindow() that i'm having trouble with (ln 207)
...
self.C4 = Tk.PhotoImage(file="temp.png")
self.card4 = self.CardCanvas.create_image(120,46,image=self.C4, state=Tk.NORMAL)
#self.CardCanvas.itemconfig(4, state=Tk.HIDDEN) # < It works here
...
self.root.mainloop()
window = MainWindow()
window.CardCanvas.itemconfig(4, state=Tk.HIDDEN) # < It doesn't work here
That's how i learned how to edit instance variables. When the window pops up, the itemconfig command doesn't actually apply like it would were it inside the class (or maybe it did and the window just didn't update?) and after closing the window I get this error:
_tkinter.TclError: invalid command name
which I assume is just because it's trying to apply a method to variables that don't exist anymore, now that the window has closed.
So I guess here's my big question - I have a MainWindow class, and from what I can tell, nothing can be changed from outside of the class because the Tk.mainloop() is running and won't stop to let other code after it run, like the itemconfig. How do I go about changing those variables? Code after the instance variable declaration doesn't seem to run until the MainWindow() is closed.

You are correct that code after mainloop doesn't run. It does, but only after the GUI has been destroyed. Tkinter is designed for the call to mainloop be the last (or very nearly last) line of executable code. Once it is called, all other work must be done as reaction to events. That is the essence of GUI programming.
The answer to "how do I go about changing the variables" is simple: do it before you call mainloop, or do it in reaction to an event. For example, do it in a callback to a button, do it in a function bound to an event, or to a time-based event via after, and so on.

Python: why must Tkinter class instantiation use a Frame?

If I want to create a Tkinter GUI simply with statements, I can do this:
from Tkinter import *
root = Tk()
root.title("Test Window")
tkFrame = Frame(root)
tkButton = Button(tkFrame)
[...]
The documentation, however, advises that Tkinter be used with a class definition, subclassing a Frame widget:
class App(Frame):
[...]
I would like to understand why that is so. Why can't we subclass the Frame's container, the window? It appears that is what is done with statements in the first example, so why not in a class definition?
EDIT (following Bryan Oakley's answer):
I would like to instantiate at the highest level of Tkinter, which I assume to be Tk() (though I have come across references stating Frame is the top level, but never mind). Indeed, the following will create a window:
from Tkinter import *
class Application(Tk):
pass
app = Application()
app.mainloop()
...but as soon as I try to add widgets I either get errors or two windows, with the widgets in a new window, depending on how I structure the code. Here's a basic example that will produce a second window with the button:
from Tkinter import *
class Application(Tk):
tkBtn = Button()
tkBtn.pack()
app = Application()
app.mainloop()
Anything more, using self, __init__, etc., produces errors. Could someone point me to working code that instantiates Tkinter at the highest level? Just like all the Frame subclasses I'm seeing, but at the highest level?

There is nothing that says a tkinter class must inherit from a frame. You can inherit from any of the tkinter widgets, or any other classs. If you have found documentation that states otherwise, that documentation is wrong. Using Frame is a logical choice since it is designed to be a container of other widgets, but it is not the only choice.
Personally I inherit from a frame because I find it convenient. Some of my GUIs need the ability to open more than one identical window. By having my main code in a Frame I am able to create multiple windows simply by creating multiple instances of the frame, and packing them in Toplevel widgets.
When you inherit from Tk, you can only have a single instance. In the real world that's usually enough, and there's absolutely nothing wrong with doing it that way. Since I personally write a fair number of tkinter programs, having them all start out exactly the same is convenient for me.
Another good choice is a Canvas since you can easily add a background image, which is not something you can do with a Frame.
Bottom line: you are absolutely not required to inherit from Frame. Inherit from whatever you want.
(the following was written in response to an edit of the original question)
In reference to this code:
from Tkinter import *
class Application(Tk):
tkBtn = Button()
tkBtn.pack()
app = Application()
app.mainloop()
The reason you see two windows is that you're not creating the class properly. You need to call the __init__ method of the superclass before creating widgets, because that's what actually creates the root window. Because you don't, you end up with two windows. You get one that is created implicitly when you add a button to a not-yet-constructed root window, and you get another when your subclass finishes initializing.
The solution is to not take shortcuts, and instead initialize the class properly:
from Tkinter import *
class Application(Tk):
def __init__(self):
Tk.__init__(self)
tkBtn = Button()
tkBtn.pack()
app = Application()
app.mainloop()
Note that this isn't a tkinter-specific problem. When subclassing, unless you have explicit reasons to do otherwise, you always should call the __init__ method of the superclass.
You asked for working examples, here are a couple:
https://stackoverflow.com/a/22424245/7432
https://stackoverflow.com/a/11405393/7432
You might also want to read the responses in the question Inheriting from Frame or not in a Tkinter application

Enter-Notify-Event Signal not working on gtk.ToolButton

On a happy (if not irrevelent) note, this is the absolute last obstacle in this particular project. If I fix this, I have my first significant dot release (1.0), and the project will be going public. Thanks to everyone here on SO for helping me through this project, and my other two (the answers help across the board, as they should).
Now, to the actual question...
I have a toolbar in my application (Python 2.7, PyGTK) which has a number of gtk.ToolButton objects on it. These function just fine. I have working "clicked" events tied to them.
However, I need to also connect them to "enter-notify-event" and "leave-notify-event" signals, so I can display the button's functions in the statusbar.
This is the code I have. I am receiving no errors, and yet, the status bar messages are not appearing:
new_tb = gtk.ToolButton(gtk.STOCK_NEW)
toolbar.insert(new_tb, -1)
new_tb.show()
new_tb.connect("clicked", new_event)
new_tb.connect("enter-notify-event", status_push, "Create a new, empty project.")
new_tb.connect("leave-notify-event", status_pop)
I know the issue is not with the "status_push" and "status_pop" events, as I've connected all my gtk.MenuItem objects to them, and they work swimmingly.
I know that gtk.ToolButton objects are in the Widgets class, so "enter-notify-event" and "leave-notify-event" SHOULD technically work. My only guess is that this particular object does not emit any signals other than "clicked", and thus I'd have to put each in a gtk.EventBox.
What am I doing wrong here? How do I fix this?
Thanks in advance!

Your guess was correct, you should wrap your widget in a gtk.EventBox, here is an example that i hope will be hopeful:
import gtk
def callback(widget, event, data):
print event, data
class Win(gtk.Window):
def __init__(self):
super(Win, self).__init__()
self.connect("destroy", gtk.main_quit)
self.set_position(gtk.WIN_POS_CENTER)
self.set_default_size(250, 200)
tb = gtk.ToolButton(gtk.STOCK_NEW)
# Wrap ``gtk.ToolButton`` in an ``gtk.EventBox``.
ev_box = gtk.EventBox()
ev_box.connect("enter-notify-event", callback, "enter")
ev_box.connect("leave-notify-event", callback, "leave")
ev_box.add(tb)
self.add(ev_box)
if __name__ == '__main__':
Win()
gtk.main()

It appears, based on experimentation and evidence, this is impossible in PyGtk 2.24.

How to make an arbirtary number of windows using Python and Tkinter?

I'm writing an app that doesn't have a main window (it runs inside a Python interpreter in another app), and I thought I had a good solution for getting Tkinter to cooperate--I made the Tkinter.Tk class into a Borg.
class RootWindow(Tk):
""" Invisible window that serves as the default parent
of all others.
"""
groupDict = {}
def __init__(self):
self.__dict__ = self.groupDict
if self.__dict__ == {}: # first instance
Tk.__init__(self)
self.withdraw()
Then I have my Windows, which are subclassed from Tkinter.Toplevel, default to parent=RootWindow(). The result should be that I can create any number of Windows and they'll use the same root.
It works once fine for the first Window, but after that things get all messed up. :(
see pic
What am I doing wrong? Is this even a feasible solution?
Thanks
EDIT: I should add that even though there's other stuff running in the picture, the problem can be duplicated just by using RootWindow as the parent of a Tkinter.Toplevel.
EDIT: I overrode Window.mainloop so everything uses the RootWindow event loop.
def mainloop(self):
self.master.wait_window(self)
Then I create each visible window like this:
test = Window()
test.mainloop()
It seems to work because the windows do show up, but their contents are packed in an odd way that's hard to describe. It alternates between no contents at all and having everything squished horizontally and expanded vertically.

One problem appears to be that you are forgetting to start the event loop. Or, based on further edits of your question, you may be starting more than one main loop. You need exactly one main loop that is run from the root window.
Tkinter certainly allows an arbitrary number of top level windows, but your question doesn't appear to have enough details to show what is wrong unless my first guess is correct.