Changing Tkinter label while app is still running - python

Could not find exact answer to my question in other posts. What I am looking for is the way to update my label while my other function is running. I tried to first change the label and then call the my_function(), but still label is not updating however my_function() is running and printing results in terminal. I am totally new to Tkinter and as far as I understood, while we do not hit window.mainloop() my label would not update. Is there any methods to update the label while other function is running?
import os
import tkinter as tk
from tkinter import END, Label, Scrollbar, Text, filedialog
def my_function(directory: str) -> None:
for item in os.scandir(directory):
if item.is_file:
# print(f'File name: {item.name}')
text_area.insert(END, f'File name: {item.name}\n')
def select_folder() -> None:
'''
Tkinter function for button,
user can select folder.
'''
path = filedialog.askdirectory()
status.config(text='Status: Work in progress, please wait!')
text_area.insert(END, 'Visited folders:\n')
my_function(path)
status.config(text='Status: Done!')
# Start the app window
window = tk.Tk()
window.title('PDF maker')
window.geometry('400x400')
# Status Label
status = Label(window, text='Status: Select the folder')
status.pack()
# Button for selecting folder
button = tk.Button(window, text='Select Folder', command=select_folder)
button.pack(side='bottom', pady=30)
# Horizontal and Vertical Scrollbars
v_s = Scrollbar(window)
v_s.pack(side='right', fill='y')
h_s = Scrollbar(window, orient='horizontal')
h_s.pack(side='bottom', fill='x')
# Text area for result output
text_area = Text(
window,
wrap='none',
font=('Times New Roman', 13),
yscrollcommand=v_s.set,
xscrollcommand=h_s.set
)
text_area.pack(padx=10, pady=10, expand=True, fill='both')
# Adding scrollability to text
v_s.config(command=text_area.yview)
h_s.config(command=text_area.xview)
window.mainloop()
Update
Or should I create 2 functions for one button? First function will change the label and text, and second function will run my_func().

As so often, the answer is very simple.
Try this:
#...
def select_folder() -> None:
"""
Tkinter function for button,
user can select folder.
"""
status.config(text="Status: Work in progress, please wait!") # switched lines here
path = filedialog.askdirectory()
text_area.insert(END, "Visited folders:\n")
my_function(path)
status.config(text="Status: Done!")
#...
Previously it did not work as intended, because filedialog.askdirectory() blocks the program-flow ( similarly to input() ).

Related

How to open the initial window in tkinter again?

I have a following question. I want to make a button in tkinter that will delete existing changes and the window will looks like the initial window.
This is my initial Window 1:
This is how the window looks like when I click on the first two buttons, Window 2:
Now I would like to click on the "Zpět" button and I want to see Window 1 again.
Here is my code:
import tkinter as tk
root = tk.Tk()
home_frame = tk.Frame(root)
home_frame.grid(row=0, column=0, sticky="news")
def raise_new_payment():
tk.Label(text=f"Stav bilance k 2021-09-09").grid()
def back():
"""I would like to this function to clean everything."""
tk.Label().destroy()
platba = tk.Button(
home_frame,
text="Zadej novou platbu",
command=lambda: raise_new_payment(),
)
platba.pack(pady=10)
zpet = tk.Button(
home_frame,
text="Zpět",
command=back,
)
zpet.pack(pady=10)
I don't know how to use the back() function. I tried to delete the tk.Label as created in raise_new_payment(), but it did not work. Can you help me please? Thanks a lot.
I would suggest you create the label once and don't call .pack() on it first, i.e. it is not visible initially.
Then update it inside raise_new_payment() and call .pack() to show it.
You can call .pack_forget() to hide it again inside back().
import tkinter as tk
root = tk.Tk()
home_frame = tk.Frame(root)
home_frame.grid(row=0, column=0, sticky="news")
def raise_new_payment():
# update label and show it
lbl.config(text=f"Stav bilance k 2021-09-09")
lbl.pack()
def back():
# hide the label
lbl.pack_forget()
platba = tk.Button(
home_frame,
text="Zadej novou platbu",
command=lambda: raise_new_payment(),
)
platba.pack(pady=10)
zpet = tk.Button(
home_frame,
text="Zpět",
command=back,
)
zpet.pack(pady=10)
# create the label and initially hide it
lbl = tk.Label(home_frame)
root.mainloop()

Automatically updating a value through a OptionMenu tkinter object

I would like to write a tkinter app that will automatically update a value based on the current state of the OptionMenu object. Here's what I have so far
from tkinter import *
root = Tk()
def show():
myLabel=Label(root,text=clicked.get()).pack()
clicked=StringVar()
clicked.set("1")
drop = OptionMenu(root,clicked,"1","2","3")
drop.pack()
myButton = Button(root,text="show selection",command=show)
root.mainloop()
In this version, the text can only be updated by clicking a button. How can I make the text update automatically, without this "middle man"?
You can simply assign clicked to the textvariable of the Label, then whenever an option is selected, the label will be updated:
import tkinter as tk
root = tk.Tk()
clicked = tk.StringVar(value="1")
drop = tk.OptionMenu(root, clicked, "1", "2", "3")
drop.pack()
tk.Label(root, textvariable=clicked).pack()
root.mainloop()
After changing some things, i got it working.
It is better to use the config() function to change item's attributes, and another important thing is to not pack() the objects (the Label, in this case) in the same line that the variable declaration.
Like so, you'll be able to change the text. Here is your code updated!
from tkinter import *
def show():
myLabel.config(text = clicked.get())
root = Tk()
clicked=StringVar( value="1")
myLabel=Label(root, text="click the button at the bottom to see this label text changed")
myLabel.pack()
drop = OptionMenu(root, clicked, "1","2","3")
drop.pack()
myButton = Button(root, text="show selection", command=show)
myButton.pack()
root.mainloop()

How to get the entry text and display in another entry?

I just want that when I type my name inside the entry box then appears in another entry with some add text. The idea is type in the entry below and after that it showed in the big entry.I was looking for this solution, but just found place in Label. I don't want in Label. The window is more big, must drag to show the entry. There's is a picture that i use in this script:
from tkinter import *
from PIL import Image, ImageTk
root = Tk()
cat = Entry(root)
cat.place(x=48, y=25, width= 350, height=140)
user = Entry(root)
user.place(x=75, y=550)
btn = Button(root, text='START')
btn.place(x=220, y=410)
root.mainloop()
#
Ok, It works the way you told me,thank you!
But now i'm facing another problem.
The problem is when i insert the function of the game in the second window. I tested in one window and it works, but when i place the function in the second window gives an error when i press the "Start" button:
'''user_try = int(txt.get())
NameError: name 'txt' is not defined'''
When i press reset button gives another error:
'''user_try = int(txt.get())
NameError: name 'txt' is not defined'''
So i know that is missing definition, but i don't know how to make a reference for this command that it's in the second window. Like i said running with just one window the program works.
Maybe i should make using class, i don't know, but i wish to make this way that i started. However if there's no other way to do as i'm doing, let's go.
I just simplify the script here, actualy the main script is more bigger, so my idea is when open the program, there is a window and the user read the instructions about the game and proceed open the second window. The window have pictures and some hidden buttons in the next picture, so there will be an interactivity with the environment.
The guess number is just the beggining. After that there will be new challeges.
I'm very excited doing this, but i'm stuck in this point. The part one i finished, the pictures, the hidden buttons it's exacly the way i want, but the challenge stops here in this problem.
from tkinter import *
from PIL import Image, ImageTk, ImageSequence
import random
from tkinter import messagebox
pc = random.randint(1,10)
def reset():
global pc
pc = random.randint(1,10)
cat['text'] = 'Ok! Lets Try Again!'
def openwin2():
win1.withdraw()
win2 = Toplevel()
win2.geometry('350x300+180+100')
win2.title('second window')
txt = Entry(win2)
txt.place(x=10,y=10)
cat = Label(win2,wraplength=300)
cat.place(x=10,y=50)
cat.config(text='Hi! I Am thinking a number between 1 and 10.')
btn = Button(win2,text='start',command=check)
btn.place(x=30, y=150)
btn2 = Button(win2, text='reset', command=reset)
btn2.place(x=110,y=150)
win2.mainloop()
def check():
user_try = int(txt.get())
if user_try < pc:
msg = 'Hmmmm... the number, which I thought of, is greater than this.'
elif user_try > pc:
msg = 'How about trying a smaller number ?!'
elif user_try == pc:
msg = 'Well Done! You guessed! It was %s the number!' % user_try
else:
msg = 'Something Went Wrong...'
cat['text'] = msg
win1 = Tk()
win1.title('First Window')
win1.geometry('350x300')
user = Label(win1,text='first window')
user.place(x=10,y=10)
btn1 = Button(win1,text='Open Window 2', command=openwin2)
btn1.place(x=10,y=50)
win1.mainloop()
There are multiple ways to do this in tkinter, here's a rework of your code using StringVar objects set to the textvariable properties of your Entry objects:
import tkinter as tk
def doit():
out_string.set("Hello " + in_string.get())
root = tk.Tk()
in_string = tk.StringVar()
out_string = tk.StringVar()
cat = tk.Entry(root, textvariable=in_string)
cat.place(x=20, y=25, width=100)
user = tk.Entry(root, textvariable=out_string)
user.place(x=20, y=75)
btn = tk.Button(root, text='START', command=doit)
btn.place(x=20, y=150)
root.mainloop()
Per #Mike-SMT, here's a different approach using Entry.get() and Entry.insert(). It augments the text when the user clicks the button:
import tkinter as tk
def doit():
user.insert(tk.END, cat.get())
root = tk.Tk()
cat = tk.Entry(root)
cat.place(x=20, y=25, width=100)
user = tk.Entry(root)
user.place(x=20, y=75)
user.insert(0, "Hello ")
btn = tk.Button(root, text='START', command=doit)
btn.place(x=20, y=150)
root.mainloop()
However, you'll see that subsequent button clicks keep appending the text. When working with Entry.insert(), you need to work with Entry.delete() and/or other Entry methods to properly manipulate the text.

Updating a label from an entry field on button push with tkinter in Python 3.5.2

I am trying to create a window with a line label, an entry field, a current value label, and an "Update Value" button.
Here is an example:
This is what I have so far. I can get the entered value to print to console, but I can't seem to work out how to get an entered value and change the currentValue Label to reflect that value by pressing the button:
from tkinter import*
main=Tk()
#StringVar for currentValue in R0C2
currentValue = StringVar(main, "0")
#Called by the setValues button, looks for content in the entry box and updates the "current" label
def setValues():
content = entry.get()
print(content)
#This kills the program
def exitProgram():
exit()
#Title and window size
main.title("Title")
main.geometry("350x200")
#Descriptions on the far left
Label(main, text="Duration (min): ").grid(row=0, column=0)
#Entry boxes for values amidship
entry=Entry(main, width=10)
entry.grid(row=0, column=1)
#Displays what the value is currently set to.
currentValue = Label(textvariable=currentValue)
currentValue.grid(row=0,column=2)
#Takes any inputted values and sets them in the "Current" column using def setValues
setValues=Button(text='Set Values',width=30,command=setValues)
setValues.grid(row=9, column=0, columnspan=2)
#Red button to end program
exitButton=Button(main, text='Exit Program',fg='white',bg='red',width=30, height=1,command=exitProgram)
exitButton.grid(row=20, column = 0, columnspan=2)
main.mainloop()
There are a couple of problems with your code.
Firstly, you are overwriting the setValues function with the setValues Button widget, and similarly, you are overwriting the currentValue StringVar with the currentValue Label.
To set a StringVar, you use its .set method.
Don't use plain exit in a script, that's only meant to be used in an interactive interpreter session, the proper exit function is sys.exit. However, in a Tkinter program you can just call the .destroy method of the root window.
Here's a repaired version of your code.
import tkinter as tk
main = tk.Tk()
#StringVar for currentValue in R0C2
currentValue = tk.StringVar(main, "0")
#Called by the setValues button, looks for content in the entry box and updates the "current" label
def setValues():
content = entry.get()
print(content)
currentValue.set(content)
#This kills the program
def exitProgram():
main.destroy()
#Title and window size
main.title("Title")
main.geometry("350x200")
#Descriptions on the far left
tk.Label(main, text="Duration (min): ").grid(row=0, column=0)
#Entry boxes for values amidship
entry = tk.Entry(main, width=10)
entry.grid(row=0, column=1)
#Displays what the value is currently set to.
currentValueLabel = tk.Label(textvariable=currentValue)
currentValueLabel.grid(row=0,column=2)
#Takes any inputted values and sets them in the "Current" column using def setValues
setValuesButton = tk.Button(text='Set Values',width=30,command=setValues)
setValuesButton.grid(row=9, column=0, columnspan=2)
#Red button to end program
exitButton = tk.Button(main, text='Exit Program',fg='white',bg='red',width=30, height=1,command=exitProgram)
exitButton.grid(row=20, column = 0, columnspan=2)
main.mainloop()
BTW, it's a Good Idea to avoid "star" imports. Doing from tkinter import * dumps 130 names into your namespace, which is unnecessary and creates the possibility of name collisions, especially if you do star imports from several modules. It also makes the code less readable, since the reader has remember which names you defined and which ones came from the imported module(s).
In my opinion the easiest way to do this would be using an object orientated method. This way you could declare a button with a command that calls a def which runs self.label.configure(text=self.entry.get()).
This can be seen below:
import tkinter as tk
class App:
def __init__(self, master):
self.master = master
self.label = tk.Label(self.master)
self.entry = tk.Entry(self.master)
self.button = tk.Button(self.master, text="Ok", command=self.command)
self.label.pack()
self.entry.pack()
self.button.pack()
def command(self):
self.label.configure(text=self.entry.get())
root = tk.Tk()
app = App(root)
root.mainloop()
The above creates a label, entry and button. The button has a command which calls a def within the class App and updates the value of the label to be the text contained within the entry.
This all works very smoothly and cleanly and more importantly is drastically easier (in my opinion) to read and update in the future.
From your code you are setting the 'currentValue', which is a StringVar:
#StringVar for currentValue in R0C2
currentValue = StringVar(main, "0")
to an object Label further down in your code. You cannot do this!
#Displays what the value is currently set to.
currentValue = Label(textvariable=currentValue) ** this line is wrong
currentValue.grid(row=0,column=2)
You should name the label something different like:
#Displays what the value is currently set to.
lblCurrentValue = Label(textvariable=currentValue)
lblCurrentValue.grid(row=0,column=2)
Then in your "setValues" method you should use 'StringVar.set(value) to update the label like so:
def setValues():
content = entry.get()
currentValue.set(entry.get())------------------Here I set the value to the entry box value
print(content)
I tend to avoid stringVar and just use:
Label.config(text='*label's text*')
If you need more help I can post you my solution but try and solve it first becasue its the best way to learn. My tip is to make sure you are using correct naming conventions. In tkinter I tend to use lbl..., entryBox... etc before widgets so I know what they are and not to confuse them with variables.

How do you keep a widget in view while scrolling?

I am using Tix to automatically create a scroll bar as the content changes. I want to keep a button or two in the user's view while they scroll through the contents of the application.
I haven't seen this question for Tkinter/Tix yet so I thought I'd ask.
The following code will create a sample of the problem where the button is at a fixed point in the window, and is subject to being scrolled.
from Tkinter import *
import Tix
class some_GUI:
def __init__(self, root):
sw= Tix.ScrolledWindow(root, scrollbar=Tix.AUTO)
sw.pack(fill=Tix.BOTH, expand=1)
frame1 = Frame(sw.window)
frame1.grid(row = 0, column = 1)
frame2 = Frame(sw.window)
frame2.grid(row = 0, column = 2)
def quit():
root.quit()
for i in range(0,300):
label1 = Label(frame1, text = "foo")
label1.grid(row = i, column = 0)
button = Button(frame2, text = "Quit", command = quit)
button.pack()
root = Tix.Tk()
display = some_GUI(root)
root.mainloop()
I want the button(s) to be in "frame2" and centered vertically relative to the application's window. I tried using winfo_height/winfo_width to find the frame's height/ width to work with update, but these values didn't change with the addition of the labels and button.
Attempted/possible solutions:
I put frame2 in sw.subwidgets_all[1] by doing the following:
frame1.pack(side = LEFT)
frame2 = Frame(sw.subwidgets_all()[1])
frame2.pack(side = RIGHT)
button = Button(frame2, text = "Quit", command = quit)
button.pack(side = RIGHT)
This allows the fixed position relative to the application, but the window resizes relative to the button's parent instead of frame1. Another drawback is that the horizontal scrollbar is only relative to frame1.
Find the midpoint of the scrollbar and update the position of the buttons relative to those coordinates using place(maybe?) not sure how to accomplish this, and seeing SO solutions in general I think this might be an inefficient way of doing this.
EDIT: Although this isn't exactly what I had in mind, the following code works as per falsetru's suggestion in the comments:
from Tkinter import *
import Tix
class some_GUI:
def __init__(self, root):
def quit():
root.quit()
frame2 = Frame(root)
frame2.pack(side = RIGHT)
button = Button(frame2, text = "Quit", command = quit)
button.pack()
frame1 = Frame(root)
frame1.pack(side = LEFT)
sw= Tix.ScrolledWindow(frame1, scrollbar=Tix.AUTO)
sw.pack(fill=Tix.BOTH, expand=1)
for widget in sw.subwidgets_all():
print widget
for i in range(0,300):
label1 = Label(sw.window, text = "foo")
label1.grid(row = i, column = i)
print root.winfo_toplevel()
for widget in sw.subwidgets_all():
print widget
root = Tix.Tk()
display = some_GUI(root)
root.mainloop()
You can put the button out of ScrollWindows:
import Tix
from Tkinter import *
def build_ui(root):
sw = Tix.ScrolledWindow(root, scrollbar=Tix.AUTO)
sw.pack(side=LEFT, fill=Tix.BOTH, expand=1)
for i in range(300):
label1 = Label(sw.window, text="foo")
label1.grid(row=i, column=0)
button = Button(root, text="Quit", command=root.quit)
button.pack(side=RIGHT)
root = Tix.Tk()
build_ui(root)
root.mainloop()
The second option you mentioned could be the one that satisfies your situation, however that is computationally expensive as you will need to delete the button(s) and redraw them over and over relatively to the scrollbar up/down motion. Not only this is ugly by design but it can be an obstacle for any further scalability of your application or even lead to unexpected bugs if your application runs some serious operations.
The only realistic solution I see for your problem is to fix the button(s) on (for example the bottom of) the upper canvas (or whatever region you want to set) and outside the scrollable region as #falsetru commented you.

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