Child widgets of child widget not showing - why and how to fix it?-CodePudding

I've encountered the problem, that I can not create a child widget of a child widget. I've tried using a class to create a window with widgets and alternatively a function to see if I don't understand something about how classes work, but the failure was the same.

I've boiled down the issue to the following code:

import tkinter as tk

root = tk.Tk()
root.geometry('900x400')

frame1=tk.LabelFrame(root, text="frame1",width=800, height=400, bg='blue', bd=5).pack()
labelframe1=tk.LabelFrame(frame1, text="labelframe1",width=300, height=300, bg='green', bd=15).pack()
labelframe2=tk.LabelFrame(frame1, text="labelframe2",width=300, height=300, bg='yellow', bd=15).pack()

button1 = tk.Button(labelframe1,text="text").pack()

I don't get errors with this code, but the outcome is the same. Only the child of root is created, but not the children of the root child.

How can I create "grandchild" widgets?

CodePudding user response：

In python, x().y() returns the value of y(). Thus, when you do tk.LabelFrame(...).pack() it returns None. Therefore, when you do tk.Button(labelframe1, ...) it's the same as tk.Button(None, ..., which causes the button to be a child of the root window.

Bottom line, it's a best practice to separate widget creation from widget layout. I also personally find that grouping layout code together makes the code much easier to understand. I think it's also a good practice to explicitly define which side the widget is being packed into.

frame1=tk.LabelFrame(root, text="frame1",width=800, height=400, bg='blue', bd=5))
labelframe1=tk.LabelFrame(frame1, text="labelframe1",width=300, height=300, bg='green', bd=15)
labelframe2=tk.LabelFrame(frame1, text="labelframe2",width=300, height=300, bg='yellow', bd=15)
button1 = tk.Button(labelframe1,text="text")

frame1.pack(side="top")
labelframe1.pack(side="top")
labelframe2.pack(side="top")
button1.pack(side="top").
button1 = tk.Button(labelframe1,text="text").pack()