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How to limit the rightest Gtk.TreeViewColumn's width inside a Gtk.ScrolledWindow?

I cannot prevent the rightest column of a Gtk.TreeView to expand.
As the real Gtk.TreeView may display a greater number of rows, making it usually somewhat greater than the screen's height, it is embedded in a Gtk.ScrolledWindow. This is required. Without it, attaching an empty grid at the right of the treeview, expanding itself horizontally, would fix the problem. Based on this idea, I've tried a workaround that introduces another difficulty (see below).
I have built a minimal working example from the example from https://python-gtk-3-tutorial.readthedocs.io/en/latest/treeview.html#filtering, without filtering nor buttons; and the columns are 80 px wide at least (this works) and their content is horizontally centered. This last detail makes the horizontal expansion of the rightest column visible. In the original example, it does expand too, but as everything is left aligned, this is not really visible. I'd liked to keep the columns' content centered, without seeing the rightest expanded.
This example is minimal, but contains some helping features: you'll find clickable column titles, that will display some information about the clicked column in the console; a remove button (works fine, remove the selected rows) and a paste button that allows to paste new rows from a selection (e.g. from selected lines from a spreadsheet, but there's nothing to check the data are correct, if you paste something that does not convert to int, it will simply crash).
Workaround
A workaround I've tried consist of gathering both the treeview and a horizontally expanding empty right grid at its right inside a grid that would be put inside the Gtk.ScrolledWindow. It works, but causes other subtle problems: in some situations, the treeview does not get refreshed (it happens after a while), yet nothing prevents the main loop to refresh the view (there's no other processing in the background, for instance). To experiment this workaround: comment and uncomment the lines as described in the code below; run the program via python script.py (if you need to install pygobject in a venv, see here), notice the rightest column does not expand to the right any longer, select the 3 first rows and press "remove", then from a spread sheet, select 3 lines of dummy integers as shown below and then press "paste". Scroll down to the last rows: you'll see most of the time that the 3 pasted lines do not show up, even if it is possible to scroll over the last row. Maybe one of them will show up after some time, then another... (or simply select a row, and they'll show up). Strangely, it happens if one has just removed as many lines as one wants to paste after the removal (3 removed, 3 pasted; or 4 removed, 4 pasted etc.).
Example spreadsheet selection:
Question
So, I'd prefer to avoid the workaround (I'm afraid I may find other situations triggering a bad refreshing of the treeview), that I could not fix itself (for instance, setting self.scrollable_treelist.set_propagate_natural_height(True) proved useless, maybe I'm not using it correctly though?) and only attach the treeview itself directly in the Gtk.ScrolledWindow. How to prevent the rightest column to expand, then?
(I've tried to use a fair amount of setters and properties of the cell renderers, the treeview, the treeview columns, the scrolled window, to no avail. Some of them are still in the code below.)
Any solution using and fixing the workaround above would be accepted though.
In any case, the treeview may be scrolled, and lines may be added and removed from it without any refreshing problem.
Source Code
import gi
try:
gi.require_version('Gtk', '3.0')
except ValueError:
raise
else:
from gi.repository import Gtk, Gdk
# ints to feed the store
data_list = [(i, 2 * i, 3 * i, 4 * i, 5 * i) for i in range(40)]
class AppWindow(Gtk.Window):
def __init__(self):
super().__init__(title="Treeview Columns Size Demo")
self.set_border_width(10)
# Setting up the self.grid in which the elements are to be positioned
self.grid = Gtk.Grid()
self.grid.set_column_homogeneous(True)
self.grid.set_row_homogeneous(True)
self.add(self.grid)
# Creating the ListStore model
self.store = Gtk.ListStore(int, int, int, int, int)
for data_ref in data_list:
self.store.append(list(data_ref))
# creating the treeview and adding the columns
self.treeview = Gtk.TreeView(model=self.store)
rend = Gtk.CellRendererText()
rend.set_alignment(0.5, 0.5)
for i, column_title in enumerate([f'n×{p}' for p in [1, 2, 3, 4, 5]]):
column = Gtk.TreeViewColumn(column_title, rend, text=i)
column.set_min_width(80)
# column.set_max_width(80)
# column.set_fixed_width(80)
# column.set_sizing(Gtk.TreeViewColumnSizing(1))
column.set_alignment(0.5)
column.set_clickable(True)
column.connect('clicked', self.on_column_clicked)
self.treeview.append_column(column)
self.treeview.set_hexpand(False)
self.treeview.get_selection().set_mode(Gtk.SelectionMode.MULTIPLE)
# Put the treeview in a scrolled window
self.scrollable_treelist = Gtk.ScrolledWindow()
self.scrollable_treelist.set_vexpand(True)
self.grid.attach(self.scrollable_treelist, 0, 0, 8, 10)
self.scrollable_treelist.add(self.treeview)
# WORKAROUND
# Alternatively, embed the treeview inside a grid containing an
# empty grid to the right of the treeview
# To try it: comment out the previous line; uncomment next lines
# scrolled_grid = Gtk.Grid()
# empty_grid = Gtk.Grid()
# empty_grid.set_hexpand(True)
# scrolled_grid.attach(self.treeview, 0, 0, 8, 10)
# scrolled_grid.attach_next_to(empty_grid, self.treeview,
# Gtk.PositionType.RIGHT, 1, 1)
# self.scrollable_treelist.add(scrolled_grid)
# self.scrollable_treelist.set_propagate_natural_height(True)
# Buttons
self.remove_button = Gtk.Button(label='Remove')
self.remove_button.connect('clicked', self.on_remove_clicked)
self.paste_button = Gtk.Button(label='Paste')
self.paste_button.connect('clicked', self.on_paste_clicked)
self.grid.attach_next_to(self.remove_button, self.scrollable_treelist,
Gtk.PositionType.TOP, 1, 1)
self.grid.attach_next_to(self.paste_button, self.remove_button,
Gtk.PositionType.RIGHT, 1, 1)
self.set_default_size(800, 500)
self.show_all()
# Clipboard (to insert several rows)
self.clip = Gtk.Clipboard.get(Gdk.SELECTION_PRIMARY)
self.clip2 = Gtk.Clipboard.get(Gdk.SELECTION_CLIPBOARD)
def on_column_clicked(self, col):
print(f'col.get_sizing()={col.get_sizing()}')
print(f'col.get_expand()={col.get_expand()}')
print(f'col.get_width()={col.get_width()}')
print(f'col.get_min_width()={col.get_min_width()}')
print(f'col.get_max_width()={col.get_max_width()}')
print(f'col.get_fixed_width()={col.get_fixed_width()}')
def on_remove_clicked(self, widget):
model, paths = self.treeview.get_selection().get_selected_rows()
refs = []
for path in paths:
refs.append(Gtk.TreeRowReference.new(model, path))
for ref in refs:
path = ref.get_path()
treeiter = model.get_iter(path)
model.remove(treeiter)
# print(f'AFTER REMOVAL, REMAINING ROWS={[str(r[0]) for r in model]}')
def on_paste_clicked(self, widget):
text = self.clip.wait_for_text()
if text is None:
text = self.clip2.wait_for_text()
if text is not None:
lines = text.split('\n') # separate the lines
lines = [tuple(L.split('\t')) for L in lines] # convert to tuples
print(f'PASTE LINES={lines}')
for line in lines:
if len(line) == 5:
line = tuple(int(value) for value in line)
self.store.append(line)
win = AppWindow()
win.connect("destroy", Gtk.main_quit)
win.show_all()
Gtk.main()

tkinter - resizing empty frame

How do you force a frame to get window_height 0?
the general case where my problem occurs:
import Tkinter as Tk
class App(Tk.Frame):
def __init__(self, master):
Tk.Frame(self, master)
self.place_holder = Tk.Frame(master=self)
self.content = Tk.Frame(master=self)
self.place_holder.pack()
self.content.pack(side=Tk.RIGHT)
Tk.Button(master=self,command=self.add_something).pack(side=Tk.TOP)
self.to_destroy = []
def add_something(self):
foo = Tk.button(master=self.place_holder, command=self.destroy_last)
self.too_destroy.append(foo)
def destroy_last(self):
self.to_destroy[-1].destroy()
the problem:
As I add more elements to the place_holder, it rescales nicely.
When I remove elements from the place_holder, it rescales nicely.
EXCEPT when I remove the last element.
Before i added anything, even when i do place_holder.pack(), it will not show. But after removing the last element, the place_holder will keep the size of this last element. Is there a way to hide the place_holder again untill i add content again?
example image
The empty container at the bottom left does not contain any elements, but still has the size of the last element in it, how can i get this to disappear without removing it (i want it again in the same place)?

What is happening is that when you remove the last widget, pack no longer is managing the frame so it isn't responsible for setting the frame size.
The simplest solution is just to temporarily pack a 1x1 pixel frame, which wil cause the placeholder frame to shrink.
There's no way to make a frame of zero pixels, so this method will always result in a one pixel tall/wide area for the placeholder. If you don't want that one pixel, you can install call pack_forget on the placeholder to completely remove it from the display, and then use pack with suitable options to re-add it when you put something in it.
Example:
def destroy_last(self):
self.to_destroy.pop().destroy()
if len(self.to_destroy) == 0:
tmp = Tk.Frame(self.place_holder, width=1, height=1, borderwidth=0)
tmp.pack()
self.place_holder.update()
tmp.destroy()

Python Tkinter: Buttons for every row in a .csv?

Trying my best at learning Tkinter and failing miserably every step of the way.
I'm trying to write a GUI that creates me either a drop-down list, either a button grid, based on row entries in a .csv file that my script imports.
Thing is, both attempts went up in flames, as I am new to this.
Can anyone link me to a resource/ give me the steps for achieving what I want?

Here is the solution. Next time please paste some code you've written so we know what exactly you've tried.
import tkinter as tk
dataMatrix = [] #this will be 2d list containing csv table elements as strings
with open("filename.csv") as file:
for row in file:
dataMatrix.append(row[:-1].split(";"))
mainWindow = tk.Tk()
######## EITHER THIS
optionMenus = []
strVars = []
for i in range(len(dataMatrix)):
strVars.append(tk.StringVar(mainWindow, dataMatrix[i][0]))
#variable containing currently selected value in i-th row, initialised to first element
optionMenus.append(tk.OptionMenu(mainWindow, strVars[-1], *dataMatrix[i])) #drop-down list for i-th row
optionMenus[-1].grid(row = 0, column = i) #placing i-th OptionMenu in window
######## OR THIS
for r in range(len(dataMatrix)):
for c in range(len(dataMatrix[r])):
b = tk.Button(mainWindow, text = dataMatrix[r][c], width = 10)
#creating button of width 10 characters
b.grid(row = r, column = c)
OptionMenu
Control Variables
Generally infohost.nmt.edu and effbot.org are the best resources for learning tkinter.

Beginner Python Keyboard GUI setup

I am beginning GUI in Python 3.5, and I am trying to setup a simple qwerty keyboard. Based on the examples, I tried the following code
from tkinter import Tk, Label, RAISED, Button, Entry
self.window = Tk()
#Keyboard
labels = [['q','w','e','r','t','y','u','i','o','p'],
['a','s','d','f','g','h','j','k','l'],
['z','x','c','v','b','n','m','<']]
n = 10
for r in range(3):
for c in range(n):
n -= 1
label = Label(self.window,
relief=RAISED,
text=labels[r][c])
label.grid(row=r,column=c)
continue
This gives me the first row, but it does not return anything else. I tried simply using 10 as the range, which created the first two rows of the keyboard, but it still did not continue onto the last row.

Your issue is in the line n -= 1. Every time a label is created, you make n one less- after the first whole row, n==0, and thus the range is 0>0, and ranges never include the high bound- for c in range(0) will just drop from the loop (as it has looped through all the nonexistent contents).
A better solution involves iterating through the lists instead of through the indexes- for loops take any iterable (list, dictionary, range, generator, set, &c.);
for lyst in labels:
# lyst is each list in labels
for char in lyst:
# char is the character in that list
label = Label(... text=char) # everything else in the Label() looks good.
label.grid(...) # You could use counters for this or use ennumerate()-ask if you need.
# The continue here was entirely irrelevant.

Is this what you want it to do? Let me know if you need me to explain it further but basically what I'm doing is first filling the columns in each row. So row remains 0 and then as I loop through the column (the inner list) I fill in each of the keys, then on to the next row and etc.
from tkinter import Tk, Label, RAISED, Button, Entry
window = Tk()
#Keyboard
labels = [['q','w','e','r','t','y','u','i','o','p'],
['a','s','d','f','g','h','j','k','l'],
['z','x','c','v','b','n','m','<']]
for r in labels:
for c in r:
label = Label(window, relief=RAISED, text=str(c))
label.grid(row=labels.index(r), column=r.index(c))
window.mainloop()

How to use tkinter slider `Scale` widget with discrete steps?

Is it possible to have a slider (Scale widget in tkinter) where the possible values that are displayed when manipulating the slider are discrete values read from a list?
The values in my list are not in even steps and are situation dependent.
From all the examples I've seen, you can specify a minimum value, a maximum value and a step value (n values at a time), but my list might look like this:
list=['0', '2000', '6400', '9200', '12100', '15060', '15080']
Just as an example. To reiterate, I want it go from for instance list[0] to list[1] or list[6] to list[5] when pulling the slider.
If anyone has any other suggestion for easily being able to pick a value from hundreds of items in a list, I'm all ears. I tried the OptionMenu widget but it gets to extensive and hard get a view of.

Edit you could set the command of the slider to a callback, have that callback compare the current value to your list and then jump to the nearest by calling set() on the slider
so:
slider = Slider(parent, from_=0, to=100000, command=callback)
and:
def callback(event):
current = event.widget.get()
#compare value here and select nearest
event.widget.set(newvalue)
Edit:
to show a complete (but simple example)
try:
import tkinter as tk
except ImportError:
import Tkinter as tk
valuelist = [0,10,30,60,100,150,210,270]
def valuecheck(value):
newvalue = min(valuelist, key=lambda x:abs(x-float(value)))
slider.set(newvalue)
root = tk.Tk()
slider = tk.Scale(root, from_=min(valuelist), to=max(valuelist), command=valuecheck, orient="horizontal")
slider.pack()
root.mainloop()
i've tested this in python 2.7.6 and 3.3.2, even when dragging the slider this jumps to the nearest value to where the mouse is currently as opposed to only jumping when you let go of the slider.