How to pass information which button is clicked into another class?

Question

I've searched and read, but don't quite understand other posts and/or it doesn't reflect problem I have.

I've tried different things from similar posts, like this one: Passing variables, creating instances, self, The mechanics and usage of classes: need explanation, but apparantly, I don't understand classes, self quite enough (as can be seen I'm absolute beginner)

from tkinter import Tk, ttk, Frame, Label, StringVar, OptionMenu, Entry, Button, Toplevel
import pymysql as mdb
from functools import partial
from PIL import Image, ImageTk

class Home(object):
    def __init__(self, master):
        self.master = master
        self.master.title("Control Panel")
        self.master.configure(background="#%02x%02x%02x" % (61, 72, 73))
        self.master.geometry("475x190")
        self.master.resizable(width=False, height=False)
        self.main_frame = Frame(master, background="#%02x%02x%02x" % (61, 72, 73))
        self.main_frame.grid(row=1, column=1, columnspan=4, padx=15, pady=15)
        load1 = Image.open('plan.jpg')
        render1 = ImageTk.PhotoImage(load1)
        self.button_plan = Button(self.main_frame, image=render1, command=self.b_clicked('Planning'))
        self.button_plan.image = render1
        self.button_plan.grid(row=1, column=1, padx=12)
        self.label_plan = Label(self.main_frame, text='Planning', font='Calibri 9',
                            background="#%02x%02x%02x" % (61, 72, 73),
                            foreground="#%02x%02x%02x" % (255, 201, 14))
        self.label_plan.grid(row=2, column=1, padx=12)
        load2 = Image.open('consumption.jpg')
        render2 = ImageTk.PhotoImage(load2)
        self.button_consumption = Button(self.main_frame, image=render2, command=self.b_clicked('Consumption'))
        self.button_consumption.image = render2
        self.button_consumption.grid(row=1, column=2, padx=12)
        self.label_consumption = Label(self.main_frame, text='Consumption', font='Calibri 9',
                                   background="#%02x%02x%02x" % (61, 72, 73),
                                   foreground="#%02x%02x%02x" % (255, 201, 14))
        self.label_consumption.grid(row=2, column=2, padx=12)


    def b_clicked(self, id):
        self.button_id = id
        self.master.withdraw()
        self.second_w = Toplevel(self.master)
        self.app = Second(self.second_w, self.button_id)


class Second(object):
    def __init__(self, master, arg1):
        self.master = master
        self.master.title("Second")
        self.master.configure(background="#%02x%02x%02x" % (61, 72, 73))
        self.master.geometry("190x165")
        self.master.resizable(width=False, height=False)
        print(arg1)

root = Tk()
GUI = Home(root)
root.mainloop()

I would like to pass a variable value into another class. In this case I would like to get self.button_id value 'Planning' from class Home to be passed to class Second. Point is... I don't need just solution. I would really like to understand it and this would be a great opportunity to learn it on my own example!

Answer 1

A couple of things:

I reduced your code to get rid of all the code which is not problematic.

When you create the buttons, the command argument runs the callback function instead of just assigning it.

command=self.b_clicked('Planning')   # Will run self.b_clicked

Instead you can use a lambda expression in this assignment:

command=lambda:self.b_clicked('Planning')

In short: the function name is self.b_clicked and normally you would assign command=self.b_clicked, but as you want to pass an argument you will have to use lambda or partial, because ending a function name with parenthesis will just run the function.

As you create two buttons, your program immediately creates two new toplevel windows. When you reuse the name self.second_w for the second window you also lose the reference to the first toplevel window.

Also, you are using the name id for a variable which is not good as id is a builtin function.

Otherwise it seems to work just fine:

from tkinter import *

class Home():
    def __init__(self, master):
        self.master = master
        self.main_frame = Frame(master, bg='tan')
        self.main_frame.pack()

        self.button_plan = Button(self.main_frame, text='Plan', 
                                  command=lambda:self.b_clicked('Planning'))
        self.button_plan.grid(row=1, column=1, padx=12)

    def b_clicked(self, idty):      # "id" is a builtin function
        self.button_id = idty
        self.master.withdraw()
        self.second_w = Toplevel(self.master)
        self.app = Second(self.second_w, self.button_id)

class Second():
    def __init__(self, master, arg1):
        self.master = master
        self.master.configure(bg='tomato')
        print(arg1)

root = Tk()
GUI = Home(root)
root.mainloop()