Python Tkinter：在同一框架的相对侧放置两个标签

Question

in Tkinter I have a frame that fills the X-dimension of my root window. Inside this frame I want to place two labels: one on the left side and one on the right side. However it seems I am still using grid and sticky the wrong way and need your advice:

from Tkinter import *

root = Tk()
root.geometry("250x200")

myFrame = Frame(root, bd=1, relief="sunken")
myFrame.pack(fill=X, padx=10)

myLabel1 = Label(myFrame, text="left").grid(sticky=W)
myLabel2 = Label(myFrame, text="right").grid(sticky=E)

root.mainloop()

This code places the two labels on the left side but on top of each other. If I place them both into the same row

myLabel1 = Label(myFrame, text="left").grid(row=0, sticky=W)
myLabel2 = Label(myFrame, text="right").grid(row=0, sticky=E)

they are at the exact same position, so that myLabel2 covers myLabel1.

If I do

myLabel1 = Label(myFrame, text="left").grid(row=0, column=0, sticky=W)
myLabel2 = Label(myFrame, text="right").grid(row=0, column=1, sticky=E)

then myLabel2 is indeed right of myLabel1, but not at the right side of the frame (although the frame is not resized).

I guess the actual question is: how do I get grid to expand to the whole frame (in x-dimension), so that sticky=E means indeed "right side of the frame" and not "right side of the first column which is as wide as myLabel1".

Answer 1

In order to put myLabel2 on the right side of the frame, you need to use myFrame.columnconfigure(1, weight=1) so that the column 1 will expand to fill the frame.

If you do

myFrame.columnconfigure(0, weight=1)
myFrame.columnconfigure(1, weight=1)

then each column will take half the frame, but you can also specify different weights to have one column bigger than the other. The columns for which you have not specified any weight adjust their width to fit their content.

The method rowconfigure does exactly the same but for rows.

Answer 2

I guess the actual question is: how do I get grid to expand to the whole frame (in x-dimension), so that sticky=E means indeed "right side of the frame" and not "right side of the first column which is as wide as myLabel1"

The short answer to that is to make sure that within a frame, at least one column has a non-zero weight. The weight attribute of a column tells tkinter how to distribute any extra space. The default is zero, meaning that a column won't get any extra space. The extra space goes unused to the right and below the last column and row.

note: the weight value can be any positive integer. The numbers are relative, so a weight of 2 will create a column that gets twice as much extra space as a column with a weight of 1.

As a rule of thumb, you should always designate at least one row and one column to have a positive weight. Usually this is the "hero" widget (typically a canvas or text widget), but it can also be an empty row or column used as a spacer.

Layout is highly dependent on everything that is in a container. If you are only ever going to have just the two labels, I recommend creating a three column configuration. myLabel1 can go in column 0, myLabel2 can go in column 2, and you can configure column 1 to be empty and to fill all of the empty space

myLabel1 = Label(...)
myLabel2 = Label(...)

myLabel1.grid(row=0, column=0, sticky="w")
myLabel2.grid(row=0, column=2, sticky="e")

myFrame.grid_columnconfigure(1, weight=1)
myFrame.grid_rowconfigure(0, weight=1)

Another option would be to go with just two columns, and let each column have an equal weight so all extra spaces is evenly divided between the two columns.