How to horizontally center a widget using grid()?

Question

I am using grid() to place widgets in a tkinter window. I am trying to put a label on the horizontal center of a window and have it stay there, even if the window is resized. How could I go about doing this?

I don't want to use pack(), by the way. I would like to keep using grid().

Answer 1

There's no trick -- the widget is centered in the area allocated to it by default. Simply place a label in a cell without any sticky attributes and it will be centered.

Now, the other question is, how to get the area it is allocated to be centered. That depends on many other factors, such as what other widgets are there, how they are arranged, etc.

Here's a simple example showing a single centered label. It does this by making sure the row and column it is in takes up all extra space. Notice that the label stays centered no matter how big you make the window.

import Tkinter as tk

class Example(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        label = tk.Label(self, text="This should be centered")
        label.grid(row=1, column=1)
        self.grid_rowconfigure(1, weight=1)
        self.grid_columnconfigure(1, weight=1)

if __name__ == "__main__":
    root = tk.Tk()
    Example(root).grid(sticky="nsew")
    root.grid_rowconfigure(0, weight=1)
    root.grid_columnconfigure(0, weight=1)
    root.mainloop()

You can get a similar effect by giving a weight to all rows and columns except the one with the label.

import Tkinter as tk

class Example(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        label = tk.Label(self, text="This should be centered")
        label.grid(row=1, column=1)

        self.grid_rowconfigure(0, weight=1)
        self.grid_rowconfigure(2, weight=1)
        self.grid_columnconfigure(0, weight=1)
        self.grid_columnconfigure(2, weight=1)

if __name__ == "__main__":
    root = tk.Tk()
    Example(root).grid(sticky="nsew")
    root.grid_rowconfigure(0, weight=1)
    root.grid_columnconfigure(0, weight=1)

    root.mainloop()