Convert Matplotlib embedding in tkinter code from defs to a class - python-3.x

Question

I am trying to convert some code from the matplotlib documentation site that embeds a matplotlib graph into tkinter from a module containing defs into a module containing a class. This code is taken directly from matplotlib (https://matplotlib.org/gallery/user_interfaces/embedding_in_tk_sgskip.html) and works exactly as expected. However for my purposes I need this in the format of a class rather than a grouping of defs within a module. Here is the original matplotlib code:
import tkinter
from matplotlib.backends.backend_tkagg import (
FigureCanvasTkAgg, NavigationToolbar2Tk)
# Implement the default Matplotlib key bindings.
from matplotlib.backend_bases import key_press_handler
from matplotlib.figure import Figure
import numpy as np
root = tkinter.Tk()
root.wm_title("Embedding in Tk")
fig = Figure(figsize=(5, 4), dpi=100)
t = np.arange(0, 3, .01)
fig.add_subplot(111).plot(t, 2 * np.sin(2 * np.pi * t))
canvas = FigureCanvasTkAgg(fig, master=root) # A tk.DrawingArea.
canvas.draw()
canvas.get_tk_widget().pack(side=tkinter.TOP, fill=tkinter.BOTH,
expand=1)
toolbar = NavigationToolbar2Tk(canvas, root)
toolbar.update()
canvas.get_tk_widget().pack(side=tkinter.TOP, fill=tkinter.BOTH,
expand=1)
def on_key_press(event):
print("you pressed {}".format(event.key))
key_press_handler(event, canvas, toolbar)
canvas.mpl_connect("key_press_event", on_key_press)
def _quit():
root.quit() # stops mainloop
root.destroy() # this is necessary on Windows to prevent
# Fatal Python Error: PyEval_RestoreThread: NULL
tstate
button = tkinter.Button(master=root, text="Quit", command=_quit)
button.pack(side=tkinter.BOTTOM)
tkinter.mainloop()
# If you put root.destroy() here, it will cause an error if the window
# is closed with the window manager.
It is easy enough to convert the figure creation portion of this code into a class, but I am unable to figure out how to get the on_key_press and the toolbar sections to code properly.
This is my class code, which creates the plot but all my attempts at adding the toolbar and having key presses work have failed.
class matplotlibAsClass:
def __init__(self, master):
self.master = master
self.frame = Frame(self.master)
self.create_chart()
self.frame.pack(expand=YES, fill=BOTH)
def create_chart(self):
fig = Figure(figsize=(5, 4), dpi=100)
t = np.arange(0, 3, .01)
fig.add_subplot(111).plot(t, 2 * np.sin(2 * np.pi * t))
canvas = FigureCanvasTkAgg(fig, self.master)
canvas.draw()
canvas.get_tk_widget().pack(side=TOP, fill=BOTH, expand=1)
if __name__ == '__main__':
root = Tk()
matplotlibAsClass(root)
root.mainloop()
Any help on how to convert the full matplotlib code, where the key presses and the toolbar works, into a fully functioning class would be greatly appreciated.
Here is code I have written that does not work:
The following code has been corrected and now works properly.
class matplotlibAsClass:
def __init__(self, master):
self.master = master
self.frame = Frame(self.master)
self.create_chart()
self.frame.pack(expand=YES, fill=BOTH)
def create_chart(self):
self.master.wm_title("Embedding in Tk")
fig = Figure(figsize=(5, 4), dpi=100)
t = np.arange(0, 3, .01)
fig.add_subplot(111).plot(t, 2 * np.sin(2 * np.pi * t))
canvas = FigureCanvasTkAgg(fig, self.master)
canvas.draw()
canvas.get_tk_widget().pack(side=TOP, fill=BOTH, expand=1)
canvas.mpl_connect("key_press_event", self.on_key_press)
toolbar = NavigationToolbar2Tk(canvas, self.master)
toolbar.update()
canvas.get_tk_widget().pack(side=TOP, fill=BOTH, expand=1)
self.button = Button(self.master, text="Quit",command=self._quit)
self.button.pack(side=BOTTOM)
def on_key_press(event):
print("you pressed {}".format(event.key))
key_press_handler(event, canvas, toolbar)
def _quit(self):
self.master.quit() # stops mainloop
#self.master.destroy()
if __name__ == '__main__':
root = Tk()
matplotlibAsClass(root)
root.mainloop()
when I run this code I get the following error:
File
"/Users/Me/Mee/python_db_programs/simpletestgui_sc_two.py",
line 104, in create_stockchart
canvas.mpl_connect("key_press_event", on_key_press)
NameError: name 'on_key_press' is not defined
After changing the on_key_press to self.on_key_press I get the following error:
File "/Users/Me/Mee/python_db_programs/simpletestgui_sc_two.py", line
111, in create_stockchart
self.button = Button(self.master,
text="Quit",command=self._quit())
TypeError: _quit() takes 0 positional arguments but 1 was given
After correcting the def _quit() to def _quit(self) I get the following error:
File
"/Users/Me/Mee/python_db_programs/simpletestgui_sc_two.py",
line 111, in create_stockchart
self.button = Button(self.master, text="Quit",
command=self._quit())
_tkinter.TclError: can't invoke "button" command: application has been
destroyed
Based upon the previous error I commented out the self.master.destroy() portion of the def _quit and now the chart loads and the toolbar works but the quit button doesn't actually cause the widget to quit.
The final correction, which I didn't fully catch from a previous comment was to change command=self._quit() to command=self._quit and now everything works correctly.