How to define Tkinter controller?

Question

Code Background: trying to have a popup window call a function in another class.

I am having trouble defining controller and configuring my functions correctly. I get an error about controller not being defined before it passes to the popupWindow class which makes sense because I have not defined controller somewhere else but I don't know where to do that:

NameError: name 'controller' is not defined

I have studied these past answers for help but am still stuck:

Calling Tkinter frame controller from function rather then button command

Calling functions from a Tkinter Frame to another

Here is my simplified code (Note: I define the various variables in the values function in other functions within the class BoundingBox but I have not included those functions for clarity and to shorten the code):

I also don't understand how to make the get_page function work which is part of my problem with figuring out how and where to define controller.

import tkinter as tk
from tkinter import *

class BoundingBox(tk.Tk):
    def __init__(self):
        tk.Tk.__init__(self)

    def get_page(self, page_class):
        return self.frames[page_class]

    def popup(self):
        self.w=popupWindow(self.master,controller)

    def values(self):     
        print(self.start_x, self.start_y, self.end_x, self.end_y, self.totwidth, self.totheight, self.value1, self.value2)
        self.allcord.append([self.start_x, self.start_y, self.end_x, self.end_y, self.totwidth, self.totheight, self.value1, self.value2])
        self.allrect.append(self.rect)
        print (len(self.allcord))     

class popupWindow(tk.Toplevel):
    def __init__(self, master, controller):
        super().__init__(master)
        self.controller = controller
        self.l1=Label(self,text="Breed")
        self.l1.grid(row=0, column=0)
        self.e1=Entry(self)
        self.e1.grid(row=0, column=1)
        self.l2=Label(self,text="Color")
        self.l2.grid(row=1, column=0)
        self.e2=Entry(self)
        self.e2.grid(row=1, column=1)
        self.b=Button(self,text='Save',command=self.cleanup)
        self.b.grid(row=2, column=1)

    def cleanup(self):
        self.value1=self.e1.get()
        self.value2=self.e2.get()
        self.controller.values()
        self.top.destroy()

if __name__ == "__main__":
    draw = BoundingBox()
    draw.mainloop()

Your `BoundingBox` class does not have a controller defined anywhere. So the `popup` function does not know it from class scope. Define it somewhere in the init. — Dschoni, Mar 09 '20 at 13:29
See this answer for a minimal working example: https://stackoverflow.com/questions/7546050/switch-between-two-frames-in-tkinter/7557028#7557028 — Dschoni, Mar 09 '20 at 13:30
You can do: `class PopupWindow(tk.Toplevel):` and use `self` instead of `top`. — stovfl, Mar 09 '20 at 14:10
@Dschoni what is the best way to define controller in the BoundingBox init? Would it be something like `controller=None`? — thegreatyonini, Mar 09 '20 at 14:42
@stovfl could you clarify? So class `PopupWindow(tk.Toplevel):` then `self=self.Toplevel(master)`? How does this relate to controller? — thegreatyonini, Mar 09 '20 at 14:45
***"How does this relate to controller? "***: It's unrelated. Don't use `self=self.Toplevel(master)` in general, you never have to assign anything to `self=`. Think of `class PopupWindow` **IS THE** `tk.Toplevel`! — stovfl, Mar 09 '20 at 14:51
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/209322/discussion-between-thegreatyonini-and-stovfl). — thegreatyonini, Mar 09 '20 at 15:57

Bryan Oakley · Accepted Answer · 2020-03-09T16:49:53.727

0

In this specific case, controller simply refers to the main window. So, you simply need to pass self as the controller argument:

def popup(self):
    self.w=popupWindow(self.master, self)

Notice how the cleanup method calls self.controller.values(). values is defined in BoundingBox, so it's clear that popupwindow was designed to have BoundingBox as the controller.

edited Mar 09 '20 at 16:49

answered Mar 09 '20 at 16:29

Bryan Oakley

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Hi @Bryan, thank you for your clear answer, I am going to try it out now. My references to `top` were a holdover that I forgot to change after @stovfl helped be modify my original init to be `super().__init__(master)`. – thegreatyonini Mar 09 '20 at 16:47

How to define Tkinter controller?

1 Answers1