Troubles laying out frames with python tkinter (frame within frame makes parent frame invisible)

Question

I'm using python to make a small app (for personal use/training) and I'm having trouble understanding how the frame module from tkinter works. All I have done so far is tried to place colored squares to "map" the window visually but I'm already having problems.

• I have set my "main" window frame as green (600*400 size, resizable)
• a container frame that's yellow (600*400, so that it should cover the whole window and so that we can see the green background from main window when resizing the window)
• and a third frame that's blue and contained in the yellow one (450*400)

Problem is, whenever I try to "print" the blue frame, the yellow one doesn't.

import tkinter

class leftFrame(tkinter.Frame):
    def __init__(self, parent):
        self.frame = tkinter.Frame(parent, width=450, height=400, bg="blue")
        self.parent = parent
        self.initialize()

    def initialize(self):
        self.frame.grid()
        #if I comment this previous line, the yellow frame will be printed
        #pass


class mainFrame(tkinter.Frame):
    def __init__(self, master=None):
        self.frame = tkinter.Frame(master, width=600, height=400, bg="yellow")
        self.master = master
        self.initialize()

    def initialize(self):
        self.frame.grid()
        self.left = leftFrame(self.frame)


root = tkinter.Tk()
root.geometry("600x400")
root.wm_title("Tkinter test")
root.configure(bg="green")
#root.resizable(False, False)

app = mainFrame(root)

root.mainloop()

I've used classes to handle my "layout objects" as it seemed a cleaner way to do so, but as I am new to python & object programming, so chances are I did something wrong there, if someone cares to explain me why this bit of code isn't working it would be a great help! Thanks ;)

Answer 1

The background of your root ends up covered by the two frames you are inserting.
I suggest the following:

-> a placeholder label was inserted to offset the inner frames, so you can see the background color of the root.

import tkinter as tk


class InnerFrame(tk.Frame):
    """A tk.Frame to be inserted in a container
    """ 
    def __init__(self, master, **kwargs):
        super().__init__(master, **kwargs)
        self.master = master


class MainFrame(tk.Frame):
    """Container for two InnerFrame
    """
    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.left_frame = InnerFrame(self, width=450, height=400, bg="blue")
        self.left_frame.grid(row=0, column=0)
        self.right_frame = InnerFrame(self, width=450, height=400, bg="green")
        self.right_frame.grid(row=0, column=1)


class App(tk.Tk):   # NOTE: not a tk.Frame
    """A tk.root that contains the entire GUI app
    """
    def __init__(self, title, color, width, height):
        super().__init__()
        self.title(title)
        self.configure(bg=color)
        self.geometry(f'{width}x{height}')

        self.placeholder_label = tk.Label(self, text='placeholder')
        self.placeholder_label.grid(row=1, column=0)

        self.mainframe = MainFrame(self)
        self.mainframe.grid()


# create and launch
App(title='Tkinter test', color='yellow', width=900, height=400).mainloop()

aspect on OSX: