Develop Reference

Python tkinter window resizes, but widgets never change or move

Python beginner. I placed a scrollbar widget in window and that works, but no matter what I do I can't get the scrollbox widget to change size. Could go with a larger scrollbox or for it to resize when the window resizes, but can't figure out how to force either to happen. Tried lots of different solutions, but feels like the grid and canvas are defaulting to a size and can't figure out how to change that. Help would be appreciated. Code is below:
import tkinter as tk
from tkinter import ttk
import os
import subprocess
class Scrollable(tk.Frame):
"""
Make a frame scrollable with scrollbar on the right.
After adding or removing widgets to the scrollable frame,
call the update() method to refresh the scrollable area.
"""
def __init__(self, frame, width=16):
scrollbar = tk.Scrollbar(frame, width=width)
scrollbar.pack(side=tk.RIGHT, fill=tk.Y, expand=True)
self.canvas = tk.Canvas(frame, yscrollcommand=scrollbar.set)
self.canvas.pack(side=tk.LEFT, fill=tk.BOTH, expand=True)
scrollbar.config(command=self.canvas.yview)
self.canvas.bind('<Configure>', self.__fill_canvas)
# base class initialization
tk.Frame.__init__(self, frame)
# assign this obj (the inner frame) to the windows item of the canvas
self.windows_item = self.canvas.create_window(0,0, window=self, anchor=tk.NW)
def __fill_canvas(self, event):
"Enlarge the windows item to the canvas width"
canvas_width = event.width
self.canvas.itemconfig(self.windows_item, width = canvas_width)
def update(self):
"Update the canvas and the scrollregion"
self.update_idletasks()
self.canvas.config(scrollregion=self.canvas.bbox(self.windows_item))
root = tk.Tk()
root.title("application")
root.geometry('750x800')
dbEnvs = ['a','b']
x = 1
header = ttk.Frame(root)
body = ttk.Frame(root)
footer = ttk.Frame(root)
header.pack(side = "top")
body.pack()
footer.pack(side = "top")
#setup Environment selection
envLabel = tk.Label(header, text="Environment:")
envLabel.grid(row=0,column=0,sticky='nw')
dbselection = tk.StringVar()
scrollable_body = Scrollable(body, width=20)
x = 1
for row in range(50):
checkboxVar = tk.IntVar()
checkbox = ttk.Checkbutton(scrollable_body, text=row, variable=checkboxVar)
checkbox.var = checkboxVar # SAVE VARIABLE
checkbox.grid(row=x, column=1, sticky='w')
x += 1
scrollable_body.update()
#setup buttons on the bottom
pullBtn = tk.Button(footer, text='Pull')
pullBtn.grid(row=x, column=2, sticky='ew')
buildBtn = tk.Button(footer, text='Build')
buildBtn.grid(row=x, column=3, sticky='ew')
compBtn = tk.Button(footer, text='Compare')
compBtn.grid(row=x, column=4, sticky='ew')
root.mainloop()
have tried anchoring, changing the window base size and multiple other things (8 or 19 different items, plus reading lots of posts), but they normally involve packing and since I used grids that normally and ends with more frustration and nothing changed.

If you want the whole scrollbox to expand to fill the body frame, you must instruct pack to do that using the expand and fill options:
body.pack(side="top", fill="both", expand=True)
Another problem is that you're setting expand to True for the scrollbar. That's probably not something you want to do since it means the skinny scrollbar will be allocated more space than is needed. So, remove that attribute or set it to False.
scrollbar.pack(side=tk.RIGHT, fill=tk.Y, expand=False)
tip: when debugging layout problems, the problems are easier to visualize when you temporarily give each widget a unique color. For example, set the canvas to one color, body to another, the instance of Scrollable to another, etc. This will let you see which parts are visible, which are growing or shrinking, which are inside the borders of others, etc.

How to display widgets on a frame that is mounted on canvas in Tkinter?

I created a main root with two frames.
-One frame is for program toolbar.
-Other frame is for canvas where data will be displayed and a scrollbar widget.
-Inside of the canvas is a third smaller frame which will be used for scrolling trough data.
However, when I try to define new widgets and place them on that third smaller frame, nothing happens. I'm defining new widgets inside of a function call of a button command. I have also tried declaring everything as global variables but without luck.
Hint: I tried placing the code from the function to the top level of the code and it works. Also, if I try to mount these widgets on the toolbar frame it also works. It seems that the only thing I can't do is to mount these new widgets on the small frame that is inside the canvas.
I used a simple for loop to create labels just for testing.
Could anyone tell what I am doing wrong?
from tkinter import *
from tkinter import ttk
#Creating main window
root = Tk()
root.resizable(width=False, height=False)
#Defining Background
toolbar = Frame(root, width=613, height=114)
toolbar.grid(row=0, column=0)
background_frame = Frame(root, width=615, height=560)
background_frame.grid(row=1, column=0)
background = Canvas(background_frame, width=615, height=560)
background.pack(side=LEFT, fill=BOTH, expand=1)
scroll_bar = ttk.Scrollbar(background_frame, orient=VERTICAL, command=background.yview)
scroll_bar.pack(side=RIGHT, fill=Y)
background.configure(yscrollcommand=scroll_bar.set)
background.bind('<Configure>', lambda e:background.configure(scrollregion = background.bbox('all')))
second_frame = Frame(background)
background.create_window(150,100, window=second_frame, anchor='nw')
def confirm1():
for x in range(100):
Label(second_frame, text = x ).grid(row=x, column=1)
show_labels = Button(toolbar, text= "Show labels", fg="black", command=confirm1)
show_labels.grid(row=0, column=2)
root.mainloop()
Picture of the app so far

I surely can't reproduce the issue with your current code, but looking at the previous edit it is pretty clear what your problem is.
(taken from your previous edit)
def confirm1():
global background_image1
background.delete('all') # <--- this line of code
for x in range(100):
Label(second_frame, text = x ).grid(row=x, column=1)
Here you delete all your items from your canvas:
background.delete('all')
hence no item appears.
You should instead delete only those items that you want to remove by passing the id or tags to delete method. You can delete multiple items together at once by giving the same tags.
Another option would be to recreate the frame item again on canvas using create_window (Do note: your frame is not deleted/destroyed, it's only removed from canvas)

Prevent a tkinter window from shrinking while allowing it to expand? [duplicate]

The size of Tkinter windows can be controlled via the following methods:
.minsize()
.maxsize()
.resizable()
Are there equivalent ways to control the size of Tkinter or ttk Frames?
#Bryan: I changed your frame1.pack code to the following:
frame1.pack(fill='both', expand=True)
frame1.bind( '<Configure>', maxsize )
And I added this event handler:
# attempt to prevent frame from growing past a certain size
def maxsize( event=None ):
print frame1.winfo_width()
if frame1.winfo_width() > 200:
print 'frame1 wider than 200 pixels'
frame1.pack_propagate(0)
frame1.config( width=200 )
return 'break'
The above event handler detects that a frame's width is too big, but is unable to prevent the increase in size from happening. Is this a limitation of Tkinter or have I misunderstood your explanation?

There is no single magic function to force a frame to a minimum or fixed size. However, you can certainly force the size of a frame by giving the frame a width and height. You then have to do potentially two more things: when you put this window in a container you need to make sure the geometry manager doesn't shrink or expand the window. Two, if the frame is a container for other widget, turn grid or pack propagation off so that the frame doesn't shrink or expand to fit its own contents.
Note, however, that this won't prevent you from resizing a window to be smaller than an internal frame. In that case the frame will just be clipped.
import Tkinter as tk
root = tk.Tk()
frame1 = tk.Frame(root, width=100, height=100, background="bisque")
frame2 = tk.Frame(root, width=50, height = 50, background="#b22222")
frame1.pack(fill=None, expand=False)
frame2.place(relx=.5, rely=.5, anchor="c")
root.mainloop()

A workaround - at least for the minimum size: You can use grid to manage the frames contained in root and make them follow the grid size by setting sticky='nsew'. Then you can use root.grid_rowconfigure and root.grid_columnconfigure to set values for minsize like so:
from tkinter import Frame, Tk
class MyApp():
def __init__(self):
self.root = Tk()
self.my_frame_red = Frame(self.root, bg='red')
self.my_frame_red.grid(row=0, column=0, sticky='nsew')
self.my_frame_blue = Frame(self.root, bg='blue')
self.my_frame_blue.grid(row=0, column=1, sticky='nsew')
self.root.grid_rowconfigure(0, minsize=200, weight=1)
self.root.grid_columnconfigure(0, minsize=200, weight=1)
self.root.grid_columnconfigure(1, weight=1)
self.root.mainloop()
if __name__ == '__main__':
app = MyApp()
But as Brian wrote (in 2010 :D) you can still resize the window to be smaller than the frame if you don't limit its minsize.

How to shrink a frame in tkinter after removing contents?

Most of the topics I came across deals with how to not shrink the Frame with contents, but I'm interested in shrinking it back after the destruction of said contents. Here's an example:
import tkinter as tk
root = tk.Tk()
lbl1 = tk.Label(root, text='Hello!')
lbl1.pack()
frm = tk.Frame(root, bg='black')
frm.pack()
lbl3 = tk.Label(root, text='Bye!')
lbl3.pack()
lbl2 = tk.Label(frm, text='My name is Foo')
lbl2.pack()
So far I should see this in my window:
Hello!
My name is Foo
Bye!
That's great, but I want to keep the middle layer interchangeable and hidden based on needs. So if I destroy the lbl2 inside:
lbl2.destroy()
I want to see:
Hello!
Bye!
But what I see instead:
Hello!
███████
Bye!
I want to shrink frm back to basically non-existence because I want to keep the order of my main widgets intact. Ideally, I want to run frm.pack(fill=tk.BOTH, expand=True) so that my widgets inside can scale accordingly. However if this interferes with the shrinking, I can live without fill/expand.
I've tried the following:
pack_propagate(0): This actually doesn't expand the frame at all past pack().
Re-run frm.pack(): but this ruins the order of my main widgets.
.geometry(''): This only works on the root window - doesn't exist for Frames.
frm.config(height=0): Oddly, this doesn't seem to change anything at all.
frm.pack_forget(): From this answer, however it doesn't bring it back.
The only option it leaves me is using a grid manager, which works I suppose, but not exactly what I'm looking for... so I'm interested to know if there's another way to achieve this.

When you destroy the last widget within a frame, the frame size is no longer managed by pack or grid. Therefore, neither pack nor grid knows it is supposed to shrink the frame.
A simple workaround is to add a small 1 pixel by 1 pixel window in the frame so that pack still thinks it is responsible for the size of the frame.
Here's an example based off of the code in the question:
import tkinter as tk
root = tk.Tk()
lbl1 = tk.Label(root, text='Hello!')
lbl1.pack()
frm = tk.Frame(root, bg='black')
frm.pack()
lbl3 = tk.Label(root, text='Bye!')
lbl3.pack()
lbl2 = tk.Label(frm, text='My name is Foo')
lbl2.pack()
def delete_the_label():
lbl2.destroy()
if len(frm.winfo_children()) == 0:
tmp = tk.Frame(frm, width=1, height=1, borderwidth=0, highlightthickness=0)
tmp.pack()
root.update_idletasks()
tmp.destroy()
button = tk.Button(root, text="Delete the label", command=delete_the_label)
button.pack()
root.mainloop()

Question: Shrink a Frame after removing the last widget?
Bind to the <'Expose'> event and .configure(height=1) if no children.
Reference:
Expose
An Expose event is generated whenever all or part of a widget should be redrawn
import tkinter as tk
class App(tk.Tk):
def __init__(self):
super().__init__()
tk.Label(self, text='Hello!').pack()
self.frm = frm = tk.Frame(self, bg='black')
frm.pack()
tk.Label(self, text='Bye!').pack()
tk.Label(frm, text='My name is Foo').pack()
self.menubar = tk.Menu()
self.config(menu=self.menubar)
self.menubar.add_command(label='delete', command=self.do_destroy)
self.menubar.add_command(label='add', command=self.do_add)
frm.bind('<Expose>', self.on_expose)
def do_add(self):
tk.Label(self.frm, text='My name is Foo').pack()
def do_destroy(self):
w = self.frm
if w.children:
child = list(w.children).pop(0)
w.children[child].destroy()
def on_expose(self, event):
w = event.widget
if not w.children:
w.configure(height=1)
if __name__ == "__main__":
App().mainloop()
Question: Re-run frm.pack(): but this ruins the order of my main widgets.
frm.pack_forget(), however it doesn't bring it back.
Pack has the options before= and after. This allows to pack a widget relative to other widgets.
Reference:
-before
Use its master as the master for the slaves, and insert the slaves just before other in the packing order.
Example using before= and self.lbl3 as anchor. The Frame are removed using .pack_forget() if no children and get repacked at the same place in the packing order.
Note: I show only the relevant parts!
class App(tk.Tk):
def __init__(self):
...
self.frm = frm = tk.Frame(self, bg='black')
frm.pack()
self.lbl3 = tk.Label(self, text='Bye!')
self.lbl3.pack()
...
def on_add(self):
try:
self.frm.pack_info()
except:
self.frm.pack(before=self.lbl3, fill=tk.BOTH, expand=True)
tk.Label(self.frm, text='My name is Foo').pack()
def on_expose(self, event):
w = event.widget
if not w.children:
w.pack_forget()
Tested with Python: 3.5 - 'TclVersion': 8.6 'TkVersion': 8.6

How to put a widget beneath widgets that are side-by-side using pack?

I try to put the widgets like this:
I don't understand why my code doesn't do that, tried to look for examples online but didn't find a solution and nothing I tried brought me closer to the requested result.
This is my code so far(if you have any comments about anything in the code feel free to tell me because it's my first try with tkinter and GUIs in general):
from Tkinter import *
class box(object):
def __init__ (self, colour,s):
self.root = root
self.listbox = Listbox(self.root, fg = colour, bg = 'black')
self.s = s
self.place_scrollbar()
self.listbox.pack(side = self.s)
def place_scrollbar(self):
scrollbar = Scrollbar(self.root)
scrollbar.pack(side = self.s, fill = Y)
self.listbox.config(yscrollcommand = scrollbar.set)
scrollbar.config(command = self.listbox.yview)
def write(self, contenet):
self.listbox.insert(END, contenet)
root = Tk()
root.resizable(False, False)
boxs = Frame(root)
boxs.pack()
box.root = boxs
server = box("red", LEFT)
client = box("green", RIGHT )
bf = Frame(root)
bf.pack(side = BOTTOM)
entry = Entry(bf,bg ='black', fg = 'white')
entry.pack()
root.mainloop()

You can't do this without using an additional frame to contain the box objects while still using pack, while still maintaining resizability.
But it is more organized in some cases to: use an additional frame to contain your box objects, by initializing it with a parent option.
Right now the widgets inside the box class are children to global root object. Which isn't really a good practice. So let's first pass and use a parent object to be used for widgets inside.
Replace:
def __init__ (self, colour,s):
self.root = root
self.listbox = Listbox(self.root, ...)
...
def place_scrollbar(self):
scrollbar = Scrollbar(self.root)
...
with:
def __init__ (self, parent, colour,s):
self.parent= parent
self.listbox = Listbox(self.parent, ...)
...
def place_scrollbar(self):
scrollbar = Scrollbar(self.parent)
...
This makes it so that you now need to initialize the object like the following:
server = box(root, "red", LEFT)
client = box(root, "green", RIGHT )
Now that we can pass a parent widget, let's create a parent frame to contain them. Actually, there's an un-used frame already, boxs let's use that by passing it as the parent as opposed to root:
server = box(boxs, "red", LEFT)
client = box(boxs, "green", RIGHT )
Now everything looks fine, optionally if you want to make it so that entry occupies as much left space as possible currently add fill='x' as an option to the pack of both the entry and the frame that contains it:
bf.pack(side = BOTTOM, fill='x')
...
entry.pack(fill='x')
Your whole code should look like:
from Tkinter import *
class box(object):
def __init__ (self, parent, colour,s):
self.parent = parent
self.listbox = Listbox(self.parent, fg = colour, bg = 'black')
self.s = s
self.place_scrollbar()
self.listbox.pack(side = self.s)
def place_scrollbar(self):
scrollbar = Scrollbar(self.parent)
scrollbar.pack(side = self.s, fill = Y)
self.listbox.config(yscrollcommand = scrollbar.set)
scrollbar.config(command = self.listbox.yview)
def write(self, contenet):
self.listbox.insert(END, contenet)
root = Tk()
root.resizable(False, False)
boxs = Frame(root)
boxs.pack()
box.root = boxs
server = box(boxs, "red", LEFT)
client = box(boxs, "green", RIGHT )
bf = Frame(root)
bf.pack(side = BOTTOM, fill='x')
entry = Entry(bf,bg ='black', fg = 'white')
entry.pack(fill='x')
root.mainloop()
Or: use grid instead of pack (with columnspan=2 option for entry).
General Answer
More generally putting a widget beneath two widgets that are side-by-side can be done by:
Encapsulating the side-by-side widgets with a frame, and then simply putting the frame above the other widget:
try: # In order to be able to import tkinter for
import tkinter as tk # either in python 2 or in python 3
except ImportError:
import Tkinter as tk
def main():
root = tk.Tk()
side_by_side_widgets = dict()
the_widget_beneath = tk.Entry(root)
frame = tk.Frame(root)
for name in {"side b", "y side"}:
side_by_side_widgets[name] = tk.Label(frame, text=name)
side_by_side_widgets[name].pack(side='left', expand=True)
frame.pack(fill='x')
the_widget_beneath.pack()
root.mainloop()
if __name__ == '__main__':
main()
Using grid:
try: # In order to be able to import tkinter for
import tkinter as tk # either in python 2 or in python 3
except ImportError:
import Tkinter as tk
def main():
root = tk.Tk()
side_by_side_widgets = dict()
the_widget_beneath = tk.Entry(root)
for index, value in enumerate({"side b", "y side"}):
side_by_side_widgets[value] = tk.Label(root, text=value)
side_by_side_widgets[value].grid(row=0, column=index)
the_widget_beneath.grid(row=1, column=0, columnspan=2)
root.mainloop()
if __name__ == '__main__':
main()
Without using additional frames, by calling pack for the_widget_beneath with side='bottom' as the first pack call, as in Bryan's comment:
try: # In order to be able to import tkinter for
import tkinter as tk # either in python 2 or in python 3
except ImportError:
import Tkinter as tk
def main():
root = tk.Tk()
side_by_side_widgets = dict()
the_widget_beneath = tk.Entry(root)
the_widget_beneath.pack(side='bottom')
for name in {"side b", "y side"}:
side_by_side_widgets[name] = tk.Label(root, text=name)
side_by_side_widgets[name].pack(side='left', expand=True)
root.mainloop()
if __name__ == '__main__':
main()
You can more easily notice reliability to global objects by creating a global main method, and add main-body of your script there and call:
...
def main():
root = Tk()
root.resizable(False, False)
boxs = Frame(root)
boxs.pack()
box.root = boxs
server = box(boxs, "red", LEFT)
client = box(boxs, "green", RIGHT )
bf = Frame(root)
bf.pack(side = BOTTOM, fill='x')
entry = Entry(bf,bg ='black', fg = 'white')
entry.pack(fill='x')
root.mainloop()
if __name__ == '__main__':
main()

How to put a widget beneath two widgets that are side-by-side using pack?
For a very simple layout like in your diagram, you simply need to pack the thing on the bottom first. That is because pack uses a "cavity" model. Each widget is organized in an unfilled cavity. Once that widget has been placed, that portion of the cavity is filled, and is unavailable for any other widgets.
In your case, you want the bottom cavity to be filled with the entry widget, so you should pack it first. Then, in the remaining upper cavity you can place your two frames side-by side, one on the left and one on the right.
For example:
import Tkinter as tk
root = tk.Tk()
entry = tk.Entry(root)
frame1 = tk.Frame(root, width=100, height=100, background="red")
frame2 = tk.Frame(root, width=100, height=100, background="green")
entry.pack(side="bottom", fill="x")
frame1.pack(side="left", fill="both", expand=True)
frame2.pack(side="right", fill="both", expand=True)
root.mainloop()
In the body of your question things get a bit more complicated, as you don't just have three widgets like your title suggests, you have several, with some being packed in the root and some being packed elsewhere, with pack statements scattered everywhere.
When using pack, it's best to group widgets into vertical or horizontal slices, and not mix top/bottom with left/right within the same group. It almost seems like you're trying to do that with your boxes, but then you don't -- your "box" is actually two widgets.
Bottom line: be organized. It also really, really helps if all of your pack (or place or grid) statements for a given parent are all in the same block of code. When you scatter them around it makes it impossible to visualize, and impossible to fix. Also, make sure that widgets have the appropriate parents.