Can't understand pack and grid geometry with tkinter - python

Hi I didn't really understand how furas made the below code work. Why didn't he get an error message about grid and pack on the same root when he added a box? In the addbox function he sets a frame to the root which is pack already and even uses the pack inside the function and then uses the grid.
Can someone please explain to me how this "magic" works?
a link to the his answer:
Creating new entry boxes with button Tkinter
from Tkinter import *
#------------------------------------
def addBox():
print "ADD"
frame = Frame(root)
frame.pack()
Label(frame, text='From').grid(row=0, column=0)
ent1 = Entry(frame)
ent1.grid(row=1, column=0)
Label(frame, text='To').grid(row=0, column=1)
ent2 = Entry(frame)
ent2.grid(row=1, column=1)
all_entries.append( (ent1, ent2) )
#------------------------------------
def showEntries():
for number, (ent1, ent2) in enumerate(all_entries):
print number, ent1.get(), ent2.get()
#------------------------------------
all_entries = []
root = Tk()
showButton = Button(root, text='Show all text', command=showEntries)
showButton.pack()
Thanks

There's no magic, it's just working as designed. The code uses pack in the root window, and uses grid inside a frame. Each widget that acts as a container for other widgets can use either grid or pack. You just can't use both grid and pack together for widgets that have the same master.

not really an answer but I think you will be helped by the link.
tkinter and it's layout is indeed a bit hard to understand.
I never understood how to deal with it until I stumbled over this presentation which explained the layout particulars in a way where I finally could get the hang of it.
Just putting it out there for others to find as well.
tkinter tutorial by beazley

I think you miss out on what pack and grid actually are. Consider such code:
import tkinter as tk
root = tk.Tk()
myFrame = tk.Frame(root)
myFrame.pack()
myButton1 = tk.Button(myFrame, text='This is button 1')
myButton2 = tk.Button(myFrame, text='This is button 2')
myButton1.grid(row=0, column=0)
myButton2.grid(row=1, column=0)
root.mainloop()
By creating root we create a new window. In this window we will put everything else. Then we create myFrame. Note, that the actual "thing" (in more adequate terms - widget) is created in line myFrame = tk.Frame(root). Note, that we have to specify where we are going to put this widget in brackets and we've written that it is going to be root - our main window. Blank frame probably isn't the best example since you can not see it being placed (not unless you use some more specifications at least), but still. We have created it, but not placed it in our user interface. The we use .pack() to place it. Now you refer to widgets as being used as packs or grids. That is not true though. Pack and grid are just the set of rules, on which the widgets are being placed inside some kind of window. Because of that, if you want to add something more to the root in our case, you will have to use .pack() again. Why? If you will give two sets of rules on how to place things on the screen for your computer - they will most likely conflict with each other. However, if we go one more level down and now want to place something inside our myFrame, we can again choose which set of rules to use. It is because it does not matter, where our frame is going to end up inside root, we now just want to specify where our Buttons 1 and 2 are going to end up inside the frame. Therefore we can again use .pack() or switch to .grid().
To conclude: .pack(), .grid() and .place() are sets of rules on how place widgets inside other widgets. In more general terms though these are rules on how place boxes in other boxes. One boxes in which we arrange other boxes can only have one set of rules.
I hope this example helps.

Related

Do frames in Tkinter contain local grid systems?

Very simple question that I cannot find the answer to on Stack Exchange. (Only this misleading thread: Python3 Tkinter: Grids Within Grids? Frames Alongside Other Frames? which sadly does not answer the question).
I am using tkinter with Python to attempt a program with a GUI. Unfortunately, I completely do not understand the grid system.
I was under the impression that each frame contains its own grid system, where 0,0 is the top-left of that frame.
I created this code:
root = Tk()
main_frame = Frame(root, width='1520', height='1080', bg='#a1a1a1').grid(row=0, column=1)
side_frame = Frame(root, width='400', height='1080', bg='#757575').grid(row=0, column=0)
header_label = Label(main_frame, text='Heading', font=('Agency', 48), bg='#a1a1a1', fg='#ffffff').grid(row=0, column=0)
And hoped that because the label is set to (0,0) in the main frame, that the label would appear in the main frame. However, it didn't. I find that a bit odd and upsetting. Below is a picture of what is instead happening - the header label is appearing in the 'side_frame'.
Faulty layout picture
Could someone please explain to me how the grid system works? I wasn't really having trouble until I tried to add a scrollbar to the main_frame - I then realised that there's some serious awkwardness embedded within tkinter and I'd like to properly understand it.
Thanks!
The problem is that you're setting main_frame and side_frame to None, so passing that as the parent for any other widget will make that widget a child of the root widget.
That is because in python x=y().z() sets the value of x to z(). Thus, when you do main_frame = Frame(...).grid(...) sets main_frame to the result of .grid(...), and grid always returns None.
You should separate widget creation from widget layout, and this is one of the reasons why. The other big reason is that it makes the code easier to read and visualize.
main_frame = Frame(root, width='1520', height='1080', bg='#a1a1a1')
side_frame = Frame(root, width='400', height='1080', bg='#757575')
main_frame.grid(row=0, column=1)
side_frame.grid(row=0, column=0)

Python Tkinter grid functions ignored

I feel like I am missing something stupidly obvious here - surely the widgets should just be positioned along the top of the root window, but they completely ignore the .grid() function.
When I printed the grid_size(), it returned (0,0). Why?!
Any help greatly appreciated :)
title = tk.Label(root, text="Enter a city below")
title.grid(row=0, column=0)
title.pack()
e = tk.Entry(root)
e.grid(row = 0, column = 1)
e.pack()
current_clicker = ttk.Button(root, text = "Current forecast", command=current)
current_clicker.grid(row=0, column=2)
current_clicker.pack()
hourly_clicker = ttk.Button(root, text = "By hour", command=hourly)
hourly_clicker.grid(row=0, column=3)
hourly_clicker.pack()
minute_clicker = ttk.Button(root, text = "By minute", command=minute)
minute_clicker.grid(row=0, column=4)
minute_clicker.pack()
daily_clicker = ttk.Button(root, text = "Daily", command=daily)
daily_clicker.grid(row=0, column=5)
print(daily_clicker.grid_size())
daily_clicker.pack()
I believe all you have to do is remove either pack() or grid(..) method. It is not recommended to mix pack() and grid(), as it might erase the effect of the other and lead to such errors.
I recommend to get rid of pack() as grid(...) is a more orderly way of managing widgets, compared to pack().
Tiny example:
hourly_clicker = ttk.Button(root, text = "By hour", command=hourly)
hourly_clicker.grid(row=0, column=3)
minute_clicker = ttk.Button(root, text = "By minute", command=minute)
minute_clicker.grid(row=0, column=4)
Hope it solved your doubts, if any more errors, do let me know
Cheers
Only one geometry manager can manage a widget at a time. So exactly like the title of the question is saying, when you call .pack() after calling .grid(...), the effects of grid(...) are ignored.
For any given widget, you must only use one, and you need to be consistent with all widgets that have the same parent.
pack, grid and place are the 3 methods available for placing a widget. tkinter refers to these as "geometry managers". Each of these provides a unique way to position and scale widgets.
pack will dock your widget to a defined or available edge
grid behaves like a table
place allows you to define an arbitrary position (and size)
An individual widget cannot have more than one geometry manager attached to it, and parents cannot contain widgets that alternate between pack and grid. This means (for example), if you have a Frame full of widgets that use pack, none of those widgets can use grid, and vise-versa. place is not subject to this limitation and can be used anywhere.

tkinter - understand pack and grid - simple layout. (always confused...)

I'm trying to configure a text box and below to the text box 3 buttons in a row centered
I don't want to expand them to fill all the area. just be at the center to stay in their original size.
I was trying to do it with pack or grid. but I'm really get confused. I also trying to to put the text box and the buttons on different frame so maybe it will separate the widgets and let me configure it without messing up things (because everything is relative to the other..) ... but I came with nothing that looks good.
I also want to learn how to use the grid in the correct way if I have all kinds of widgets and buttons one below the other without "columnspan" or adjust the text length inside the buttons as well to match the widgets above them...
In this example. How I can center the buttons? I have to use side=tkinter.LEFT in order to put them one after one in a row. but the problem that they also stick to the left...
import tkinter
window = tkinter.Tk()
frame1 = tkinter.Frame(window).pack()
textbox1 = tkinter.Text(frame1, width=70, height=15).pack(side=tkinter.TOP)
button1 = tkinter.Button(frame1, text="button1").pack(side=tkinter.LEFT)
button2 = tkinter.Button(frame1, text="button2").pack(side=tkinter.LEFT)
button3 = tkinter.Button(frame1, text="button3").pack(side=tkinter.LEFT)
window.mainloop()
in this example if I set another frame to do separation between the widgets ...
It's not get to the center either....
import tkinter
window = tkinter.Tk()
frame1 = tkinter.Frame(window).pack(side=tkinter.TOP)
textbox1 = tkinter.Text(frame1, width=70, height=15).pack(side=tkinter.TOP)
frame2 = tkinter.Frame(window).pack(side=tkinter.TOP)
button1 = tkinter.Button(frame2, text="button1").pack(side=tkinter.LEFT)
button2 = tkinter.Button(frame2, text="button2").pack(side=tkinter.LEFT)
button3 = tkinter.Button(frame2, text="button3").pack(side=tkinter.LEFT)
window.mainloop()
And in this example. with grid, if I'm using different frames the button just jump on the text box and messed up everything....
import tkinter
window = tkinter.Tk()
frame0 = tkinter.Frame(window).grid(row=0, column=0)
frame1 = tkinter.Frame(window).grid(row=1, column=0)
textbox = tkinter.Text(frame0, width=70, height=15).grid(row=0, column=0)
button1 = tkinter.Button(frame1, text="button1").grid(row=0, column=0)
button2 = tkinter.Button(frame1, text="button2").grid(row=0, column=1)
button3 = tkinter.Button(frame1, text="button3").grid(row=0, column=2)
window.mainloop()
Can someone explain to me please in which way it's better to use and how to understand it better...?
it's always confusing me...
thanks in advance,
eliran
I was trying to do it with pack or grid. but I'm really get confused.
I also trying to to put the text box and the buttons on different
frame so maybe it will separate the widgets and let me configure it
without messing up things (because everything is relative to the
other..) ... but I came with nothing that looks good.
Your second example is fairly close to working, but it has a fatal flaw. If you add some debugging statements you'll see that frame1 and frame2 are None. Thus, any widgets with those as a parent actually end up in the root window.
This is because foo().bar() always returns the result of .bar(). In tkinter, .grid(...) always returns None, so Frame(...).grid(...) will always return None.
The best practice is to always separate widget creation from widget layout. For example:
frame1 = tkinter.Frame(window)
frame2 = tkinter.Frame(window)
frame1.pack(side="top")
frame2.pack(side="top")
With that, frame1 and frame2 are properly set to the frames. And when that happens, the rest of the code in your second example works as you expect and the buttons are centered.
And in this example. with grid, if I'm using different frames the button just jump on the text box and messed up everything....
That happens for the same reason as mentioned above: you think you're using separate frames, but everything is going in the root window. Because they are all in the root window, and you put the text widget and a button in the same row and column, they overlap.
I also want to learn how to use the grid in the correct way if I have
all kinds of widgets and buttons one below the other without
"columnspan" or adjust the text length inside the buttons as well to
match the widgets above them...
grid is not the right choice in this specific case, since you aren't actually creating a grid. You can use it, but it requires more code than using pack. grid is the right choice if you're creating an actual grid. In this case you aren't.
Using grid in this case requires a little creativity. While it's not the only solution, I would recommend that you divide the bottom frame into five columns - an empty column on the left and right, and three columns in the middle for the buttons. The empty columns can be used to take up all extra space, forcing the middle columns to all be centered.
A best practice for using grid is that every window that uses grid to manage its children needs at least one row and one column with a non-zero weight. That lets tkinter know where to allocate any extra space, such as when the user resizes the window.
Here's a complete solution using grid:
import tkinter
window = tkinter.Tk()
frame0 = tkinter.Frame(window)
frame1 = tkinter.Frame(window)
window.grid_rowconfigure(0, weight=1)
window.grid_columnconfigure(0, weight=1)
frame0.grid(row=0, column=0, sticky="nsew")
frame1.grid(row=1, column=0, sticky="nsew")
frame0.grid_rowconfigure(0, weight=1)
frame0.grid_columnconfigure(0, weight=1)
textbox = tkinter.Text(frame0, width=70, height=15)
textbox.grid(row=0, column=0, sticky="nsew")
button1 = tkinter.Button(frame1, text="button1")
button2 = tkinter.Button(frame1, text="button2")
button3 = tkinter.Button(frame1, text="button3")
frame1.grid_rowconfigure(0, weight=1)
frame1.grid_columnconfigure((0,4), weight=1)
button1.grid(row=0, column=1)
button2.grid(row=0, column=2)
button3.grid(row=0, column=3)
window.mainloop()
Can someone explain to me please in which way it's better to use and how to understand it better...?
In summary, your instinct to use separate frames is the right place to start. You should divide your UI into logical groups, and use separate frames for each group. Then, you are free to pick either grid or pack for each group separately. However, you need to be diligent with grid to make sure that the sticky option is used correctly, and that you've set weights for all of the right columns.
And finally, you have to start with the proper practice of separating widget creation from widget layout.
I have had these kinds of problems before. Even though the .pack() and .grid() systems are excellent, when things are getting hectic you can use the .place() system. .place() allows you to exactly pin-point your tkinter and ttk widgets using x-y axis coordinates.
The coordinates (0,0) are not at the center but at the topmost left corner of your tkinter window.
Eg:
some_widget_name = Button(root, text="Click me!"....)
some_widget_name.place(x=100, y=50)
This will make your widget move right 100 pixels and move down 50 pixels from the topmost left corner.
However, sometimes when you really want to make the location of the widgets precise, you may have to do some trial-and-error to make it visually pleasing.

how to use text box in tkinter and use the values? python 3

How to create multi-lines in an entry widget in tkinter and use those inputs to create something?
For example, I want a textbox widget to come up and ask the user:
How many squares do you want? (ex: 4x4, 5x5)
What color do you want them?
And with the users input, I would like to create that many x-amount of squares in that specific height/width and specify the colors etc.
I am totally new to tkinter and I'm not really sure how to approach this.
I tried using this, but i'm not really sure how to add more lines and to use the values inputted.
import tkinter
from tkinter import *
class Squares:
root = Tk()
root.title('Random')
x = Label(text='How many squares? (ex: 4x4, 5x3)').pack(side=TOP,padx=10,pady=10)
Entry(root, width=10).pack(side=TOP,padx=10,pady=10)
Button(root, text='OK').pack(side= LEFT)
Button(root, text='CLOSE').pack(side= RIGHT)
You have a number of problems here.
I'm not sure what the Squares class is supposed to be doing, but it's basically not doing anything. You have a bunch of code that runs when you define the class, creating a few variables (which will end up as class attributes, shared by all instances of the class), and… that's it. Rather than try to figure out what you're intending here, I'm just going to scrap the class and make it all module-level code.
You never call root.mainloop(), so your program will just define a GUI and then never run it.
You don't bind your buttons to anything, so there's no way they can have any effect. You need to create some kind of function that does something, then pass it as the command argument, or .bind it later.
You don't store references for any of your controls, so there's no way to access them later. If you want to get the value out of the entry, you need some way to refer to it. (The exception is your x variable, but that's going to be None, because you're setting it to the result of calling pack on the Label, not the Label itself.)
Once you've done that, you just need to parse the value, which is pretty easy.
Putting it all together:
import tkinter
from tkinter import *
root = Tk()
root.title('Random')
Label(text='How many squares? (ex: 4x4, 5x3)').pack(side=TOP,padx=10,pady=10)
entry = Entry(root, width=10)
entry.pack(side=TOP,padx=10,pady=10)
def onok():
x, y = entry.get().split('x')
for row in range(int(y)):
for col in range(int(x)):
print((col, row))
Button(root, text='OK', command=onok).pack(side=LEFT)
Button(root, text='CLOSE').pack(side= RIGHT)
root.mainloop()
You just have to change that print to do something useful, like creating the squares.
If you don't need an outline for the text box, create_text would be the easiest thing, even though it doesn't have a wrap text feature(at least, in python 3 you can do this):
from tkinter import *
tk = Tk()
canvas = Canvas(tk, 1000, 1000)
canvas.pack()
canvas.create_text(200, 200, text="Example Text")
Try it!

Python Tkinter Tix: How to use ScrolledWindow with grid in Tix NoteBook

I'm adding several widgets to a Frame which is located in a tix.NoteBook. When there are too much widgets to fit in the window, I want to use a scrollbar, so I put tix.ScrolledWindow inside that Frame and add my widgets to this ScrolledWindow instead.
The problem is that when using the grid() geometry manager, the scrollbar appears, but it is not working (The drag bar occupies the whole scroll bar).
from Tkinter import *
import Tix
class Window:
def __init__(self, root):
self.labelList = []
self.notebook = Tix.NoteBook(root, ipadx=3, ipady=3)
self.notebook.add('sheet_1', label="Sheet 1", underline=0)
self.notebook.add('sheet_2', label="Sheet 2", underline=0)
self.notebook.add('sheet_3', label="Sheet 3", underline=0)
self.notebook.pack()
#self.notebook.grid(row=0, column=0)
tab1=self.notebook.sheet_1
tab2=self.notebook.sheet_2
tab3=self.notebook.sheet_3
self.myMainContainer = Frame(tab1)
self.myMainContainer.pack()
#self.myMainContainer.grid(row=0, column=0)
scrwin = Tix.ScrolledWindow(self.myMainContainer, scrollbar='y')
scrwin.pack()
#scrwin.grid(row=0, column=0)
self.win = scrwin.window
for i in range (100):
self.labelList.append((Label(self.win)))
self.labelList[-1].config(text= "Bla", relief = SUNKEN)
self.labelList[-1].grid(row=i, column=0, sticky=W+E)
root = Tix.Tk()
myWindow = Window(root)
root.mainloop()
Whenever I change at least one of the geometry managers from pack() to grid(), the problem occurs. (Actually, I'd prefer using grid() for all containers.)
When I don't use the NoteBook widget, the problem does not occur either. The other examples here all seem to rely on pack().
Any ideas?
Many thanks,
Sano
I solved it without using ´tix.scrolledWindow´. Instead, I went for the autoscrollbar suggested by Fred Lundh here.
The main problem was the adaption to the NoteBook widget. First, I tried to put the scrollbar to the root, so that they would surround the whole window. Now, I wanted to change the hook for the scrollbar whenever I changed a tab, but the ´raisecmd´ of the Notebook did not work. Next, I thought of using the configure event on each tab - whenever a new tab is raised, its size changes and configure is called.
Well, after much trying without ever being satisfied I changed my approach and put the scrollbars inside of the tabs. The tabs and all subcontainers must get the ´grid_columnconfigure(0, weight=1)´ and ´grid_rowconfigure(0, weight=1)´ settings, or else they will not grow with the tabs.

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