Access function and variable of parent(not exactly) class in tkinter of python

Question

Please see the code below I got from OysterShucker

import tkinter as tk


class Table(tk.Frame):
    def __init__(self, master, header_labels:tuple, *args, **kwargs):
        tk.Frame.__init__(self, master, *args, **kwargs)
        
        # configuration for all Labels
        # easier to maintain than directly inputting args
        self.lbl_cfg = {
            'master'     : self,
            'foreground' : 'blue',
            'relief'     : 'raised',
            'font'       : 'Arial 16 bold',
            'padx'       : 0,
            'pady'       : 0,
            'borderwidth': 1,
            'width'      : 11,
        }
        
        self.headers = []
        self.rows    = []
        
        for col, lbl in enumerate(header_labels):
            self.grid_columnconfigure(col, weight=1)
            
            # make and store header
            (header := tk.Label(text=lbl, **self.lbl_cfg)).grid(row=0, column=col, sticky='nswe')
            self.headers.append(header)
            
    def add_row(self, desc:str, quantity:int, rate:float, amt:float, pending:bool) -> None:
        print("how can I update variable total and call show_total")
        self.rows.append([])
        for col, lbl in enumerate((desc, quantity, rate, amt, pending), 1):
            (entry := tk.Label(text=lbl, **self.lbl_cfg)).grid(row=len(self.rows), column=col, sticky='nswe')
            self.rows[-1].append(entry)
            
    def del_row(self, i:int) -> None:
        for ent in self.rows[i]:
            ent.destroy()
            
        del self.rows[i]
        
        for r, row in enumerate(self.rows, 1):
            for c, ent in enumerate(row, 1):
                ent.grid_forget()
                ent.grid(row=r, column=c, sticky='nswe')

class Application(tk.Tk):
    def __init__(self, title:str="Sample Application", x:int=0, y:int=0, **kwargs):
        tk.Tk.__init__(self)

        self.title(title)
        self.config(**kwargs)
        
        header_labels = ('', 'Description', 'Quantity', 'Rate', 'Amt', 'pending')
        self.total=0
        self.table = Table(self, header_labels)
        self.table.grid(row=0, column=0, sticky='nswe')
        
        # update so we can get the current dimensions           
        self.update_idletasks()
        self.geometry(f'{self.winfo_width()}x{self["height"] or self.winfo_screenheight()}+{x}+{y}')
        
        # test
        self.table.add_row("A", 2, 12.5, 25, True)
        self.table.add_row("B", 4, 12.5, 50, False)
        self.table.del_row(0)
        self.table.add_row("A", 2, 12.5, 25, True)

    def show_total(self):
        print(self.total)
        print("Total has been updated")
        return


if __name__ == "__main__":
    # height of 0 defaults to screenheight, else use height
    Application(title="My Application", height=0).mainloop()
    

Please correct me if my understanding is wrong.
I think Table object is used by Application object.
I have put 'not exactly' in title because Table and Application are not child and parent respectively. Isn't it ?
There is a variable 'total' in Application object.
You can assume that 'total' is also affected by other widgets in Application which I have not shown because that will not be relevant to this question.
My aim is to update 'total' according to Quantity column in table . So, when entry is added to table then total should be updated and show_total function has to be called from inside add_row. Same will be case in del_row.
Also note that del_row can be called by clicking of a button inside table which I have not shown (actually, there is a delete button in every row which I have not shown to keep code short). How can this be done ?
Thanks.

Answer 1

In the Application class, you create an instance of Table by passing self:

self.table = Table(self, header_labels)

This means that the master parameter in the __init__ method of Table is an instance of Application. So, update the Table class as follows:

in the __init__ method of Table, add:

self.master = master

in add_row

self.master.total += quantity
self.master.show_total()

similarly you modify del_row as needed