Automatically resize listbox when main window is maximized (Tk) - tk-toolkit

Question

I am using grid that has inside a listbox and 3 buttons below the listbox. When I maximize the window, they stay the same, while I need them to expand. I would not like to substitute grid with pack, as I am going to make layoung more complicated, which is simpler with grid. Is it somehow possible to expand a grid or make a grid work together with a pack? Thanks.

Answer 1

You need to do two things to have a gridded widget expand as the parent resizes. The widget should use the sticky option to specify which sides of the parent container it should adhere to. You also need to tell the parent how it should distribute space as it changes size using the grid_columnconfigure and grid_rowconfigure methods.
Here is an example of a gridded listbox. You should experiment with changing the sticky options to an empty string and to various other combinations of north, east, south and west to see what happens. Also try commenting out the grid_rowconfigure and grid_columnconfigure to see how that affects things.
import tkinter as tk
def main():
root = tk.Tk()
listbox = tk.Listbox(root)
listbox.grid(sticky='NEWS')
root.grid_rowconfigure(0, weight=1)
root.grid_columnconfigure(0, weight=1)
root.mainloop()
if __name__ == '__main__':
main()
To illustrate how this can work with some extra widgets, here is another sample with buttons on the top right. The listbox now spans 3 rows and the third row (row 2) is set to get the additional space on resizing so that the buttons do not spread out.
import tkinter as tk
import tkinter.ttk as ttk
def main():
root = tk.Tk()
listbox = tk.Listbox(root)
listbox.grid(column=0, row=0, rowspan=3, sticky='NEWS')
buttonOne = ttk.Button(root, text="One")
buttonOne.grid(column=1, row=0, sticky='NE')
buttonTwo = ttk.Button(root, text="Two")
buttonTwo.grid(column=1, row=1, sticky='NE')
root.grid_rowconfigure(2, weight=1)
root.grid_columnconfigure(0, weight=1)
root.mainloop()
if __name__ == '__main__':
main()

Answer 2

When having problems with widgets not growing or shrinking properly with grid, it's usually because of one or both of the following factors:
the widget hasn't been told to "stick" to the sides of the space given to it
the master hasn't been told how to allocate extra space
The first problem can be solved with using the sticky option to grid. For example:
grid .listbox -row 0 -column 0 -sticky nsew
The second problem has to do with how grid allocates extra space. By default it will leave extra space unused. It does this by allocating extra space based on a row or columns weight, which defaults to 0 (zero).
By giving a row or column a positive weight, you are asking tk to give extra space to that row and/or that column. The amount it gets is proportional to its weight. For example, if one row has a weight of one and another has a weight of two, the one with a weight of two will get twice as much of the extra space as the other row.
As a rule of thumb when using grid, always give at least one row and one column a non-zero weight so that any extra space will get used.
Here's a complete example. Run the code and resize the window to see how everything grows and shrinks. Next, comment out the final four lines and run it again to see the effect that weight has. You might also want to experiment with setting the weight on only the middle column.
package require Tk
listbox .lb
button .b1 -text "Button 1"
button .b2 -text "Button 1"
button .b3 -text "Button 1"
grid .lb -row 0 -column 0 -columnspan 3 -sticky nsew
grid .b1 -row 1 -column 0
grid .b2 -row 1 -column 1
grid .b3 -row 1 -column 2
grid rowconfigure . 0 -weight 1
grid columnconfigure . 0 -weight 1
grid columnconfigure . 1 -weight 1
grid columnconfigure . 2 -weight 1