Python/tkinter - Getting the current value of the checkbox variable - python-3.x

I'd like to print the current value of the checkbox variable. Instead I get the last before the click. what am I doing wrong?
import tkinter as tk
def widget(frame):
chbx_value = 0
widget_col_span = 1
# widgets checkbox
var_c = tk.IntVar(master=frame, value=chbx_value)
widget_c = tk.Checkbutton(master=frame, text='', variable=var_c)
widget_c.bind("<ButtonRelease>", lambda event: print(var_c.get()))
widget_c.grid(row=0, column=0, columnspan=widget_col_span, padx=1, pady=1, sticky="ns")
root = tk.Tk()
root.title('My Window')
widget(root)
root.mainloop()

The event <ButtonRelease> obviously occurs before your variable has changed. My advice would be to use the command kwarg in the Checkbutton constructor. Besides, it probably makes more sense to use a boolean as variable:
import tkinter as tk
def widget(frame):
widget_col_span = 1
# widgets checkbox
var_c = tk.BooleanVar(master=frame)
widget_c = tk.Checkbutton(master=frame, text='', variable=var_c, command=lambda: print(var_c.get()))
widget_c.grid(row=0, column=0, columnspan=widget_col_span, padx=1, pady=1, sticky="ns")
root = tk.Tk()
root.title('My Window')
widget(root)
root.mainloop()

Related

name 'main_window' is not defined

from tkinter import *
def create_main_window():
global main_window
main_window = Toplevel()
main_window.update()
entrance_window = Tk()
first_text_label = Label(entrance_window, text="you are in:").grid(row=0, column=0)
place_entry = Entry(entrance_window).grid(row=0, column=1)
submit_button = Button(entrance_window, text="Submit", command=create_main_window).grid(row=1, column=0, columnspan=2)
Label(main_window, text=f"{place_entry}").pack()
entrance_window.mainloop()
the program should open a new window with the text from the entry box from the first window but it either shows None if I write
Label(main_window, text=f"{place_entry}").pack()
in the create_main_window or it gives me an error saying that main_window is not defined if I write it after the button code.
Can someone help with this?
Try this:
from tkinter import *
def create_main_window():
global main_window
main_window = Toplevel(main_window)
label = Label(main_window, text=f"{place_entry.get()}")
label.pack()
# main_window.update() # This is useless
entrance_window = Tk()
first_text_label = Label(entrance_window, text="You are in:")
first_text_label.grid(row=0, column=0)
place_entry = Entry(entrance_window)
place_entry.grid(row=0, column=1)
submit_button = Button(entrance_window, text="Submit", command=create_main_window)
submit_button.grid(row=1, column=0, columnspan=2)
entrance_window.mainloop()
I moved the label creation inside create_main_window. Also please note that using var = a().b(), saves what ever b() returns inside var. That is why when you use var = Entry(...).pack(...), var is always None.
This is because you are trying to add a Label to an object that doesn't exist. Move the Label function to the create_main_window() function, like below:
from tkinter import *
def create_main_window():
global main_window, entrance_window
main_window = Toplevel()
place_entry = Entry(entrance_window).grid(row=0, column=1)
Label(main_window, text=f"{place_entry}").pack()
main_window.update()
entrance_window = Tk()
first_text_label = Label(entrance_window, text="you are in:").grid(row=0, column=0)
submit_button = Button(entrance_window, text="Submit", command=create_main_window).grid(row=1, column=0, columnspan=2)
entrance_window.mainloop()

Show tkinter widget when checkbox is checked

I'm trying to make the entry widget show once the checkbutton is checked and hide when it's not.
from tkinter import *
master = Tk()
master.geometry('500x400')
other = IntVar()
Checkbutton(master, text="Other", variable=other, command=toggle()).grid(row=10, sticky=W)
def toggle():
if other.get()==1:
Entry(master,width=50).grid(row=11, sticky=W)
else:
Entry(master,width=50).grid_remove()
Try this:
from tkinter import *
def toggle():
if other.get():
ent.grid(row=11, sticky=W)
else:
ent.grid_forget()
master = Tk()
master.geometry('500x400')
other = BooleanVar()
Checkbutton(master, text="Other", variable=other, command=toggle).grid(row=10, sticky=W)
ent=Entry(master,width=50)
master.mainloop()

Confused about binding the enter key in tkinter

This is a search bar program and once enter is hit it will open google with whatever I searched:
import tkinter as tk
from tkinter import ttk
import webbrowser
root = tk.Tk()
root.title("Search Bar")
label1 = ttk.Label(root, text="Query")
label1.grid(row=0, column=0)
entry1 = ttk.Entry(root, width=50)
entry1.grid(row=0, column=1)
def callback():
webbrowser.open("http://google.com/search?q="+entry1.get())
def get(event):
webbrowser.open("http://google.com/search?q=" + entry1.get())
button1 = ttk.Button(root, text="Search", width=10, command=callback)
button1.grid(row=0, column=2)
entry1.bind("<Return>", get)
root.mainloop()
What I'm most confused about is why did I need a second function [get(event)] in order to bind the enter key at entry1.bind("<Return>", get). Why couldn't I just put entry1.bind("<Return>", callback) (which is for the button). For some reason, the enter bind function requires a parameter and I'd just like an explanation as to why that is? Even though whatever is in the parameter is not being called.
You can use event=None in
def callback(event=None):
and then you can use with command= and bind()
bind() will run it with event, command= will run it without event and it will use None
import tkinter as tk
from tkinter import ttk
import webbrowser
def callback(event=None):
webbrowser.open("http://google.com/search?q="+entry1.get())
root = tk.Tk()
root.title("Search Bar")
label1 = ttk.Label(root, text="Query")
label1.grid(row=0, column=0)
entry1 = ttk.Entry(root, width=50)
entry1.grid(row=0, column=1)
button1 = ttk.Button(root, text="Search", width=10, command=callback)
button1.grid(row=0, column=2)
entry1.bind("<Return>", callback)
root.mainloop()
bind() can be used with different events and objects so it send this information to function - ie. event.widget - so you can bind the same function to different objects.
def callback(event=None):
print(event)
if event: # if not None
print(event.widget)
You can use
def callback(event=None):
Or u can pass None as parameter
import tkinter as tk
from tkinter import ttk
import webbrowser
root = tk.Tk()
root.title("Search Bar")
label1 = ttk.Label(root, text="Query")
label1.grid(row=0, column=0)
entry1 = ttk.Entry(root, width=50)
entry1.grid(row=0, column=1)
def callback():
webbrowser.open("http://google.com/search?q="+entry1.get())
def get(event):
webbrowser.open("http://google.com/search?q=" + entry1.get())
button1 = ttk.Button(root, text="Search", width=10, command=lambda x=None:get(x))
button1.grid(row=0, column=2)
entry1.bind("<Return>", get)
root.mainloop()

I am having trouble making an input text box that goes through a function and outputs test to an output textbox with Tkinter

im new to Python3.6.2
So I want a program that takes an input (Via text box from tkinter) and outputs a word in my custom "language"
with this function
def Mescre(n):
Words = (n)
Mes = str.maketrans('abcdefghijklmnopqrstuvwxyz', 'ektnopzcamjqwyuxsbfdiglhrv')
print(Words.translate(Mes))
and here's what i want the window to look like
from tkinter import*
root = Tk()
Mescre = Label(root, text="Input:")
English = Label(root , text="Output:")
label1.grid(row=0, sticky=E)
label2.grid(row=1, sticky=E)
entry1 = Entry(root)
entry2 = Entry(root)
entry1.grid = (row=0, column=1)
entry2.grid = (row=1, column=1)
root.mainloop()
if "hello" was in the Input text box, i want the output to be "coqqu" in the Output text box.
See my example below:
from tkinter import *
class App:
def __init__(self, root):
self.root = root
self.sv = StringVar()
self.Mes = str.maketrans('abcdefghijklmnopqrstuvwxyz', 'ektnopzcamjqwyuxsbfdiglhrv')
self.entry = Entry(self.root, textvariable = self.sv)
self.label = Label(self.root)
self.entry.pack()
self.label.pack()
self.sv.trace("w", self.callback)
def callback(self, *args):
self.label.configure({"text": self.entry.get().translate(self.Mes)})
root = Tk()
App(root)
root.mainloop()
Here we define a StringVar() to be the value of the attribute textvariable for the Entry widget.
We then assign a callback to a trace() on the variable so that whenever the variable is updated (When someone types in the Entry) we call callback().
Within callback() we use configure() on the Label widget in order to set the text to equal the post translation version of the value of the Entry widget.
This creates a "live updating" translation effect.
Here's a basic example:
import tkinter as tk
root = tk.Tk()
def Mescre():
val = textfield.get()
Words = (val)
Mes = str.maketrans('abcdefghijklmnopqrstuvwxyz', 'ektnopzcamjqwyuxsbfdiglhrv')
print(Words.translate(Mes))
textfield = tk.Entry(root)
textfield.pack()
button = tk.Button(root, command=Mescre, text='Push')
button.pack()
root.mainloop()
Updated:
import tkinter as tk
root = tk.Tk()
def Mescre():
val = textfield.get()
Words = (val)
Mes = str.maketrans('abcdefghijklmnopqrstuvwxyz', 'ektnopzcamjqwyuxsbfdiglhrv')
translation = Words.translate(Mes)
#print(translation)
outputfield.delete(0, tk.END)
outputfield.insert(0, translation)
textfield = tk.Entry(root)
textfield.pack()
outputfield = tk.Entry(root)
outputfield.pack()
button = tk.Button(root, command=Mescre, text='Push')
button.pack()
root.mainloop()

Python 3.3 TkInter window closes unexpectedly. Why?

I came up with the following code more as a reference to help me remember how to build GUI apps with TkInter. It runs great except when a click Button1 or any other widget whose command option is set to self.hello. As you can see in the code bellow, the hello function is like a place holder. While the button click works fine while running the script through IDLE, it simply causes the application to exit if you start the program by double-clicking the actual file test.pyw. My question is, why?
#Some guy somewhere
from tkinter import *
class Application:
def hello(self):
msg = messagebox.showinfo('Message Title','Message Body')
def __init__(self, parent):
parent.resizable(0,0)
parent.minsize(800, 400)
parent.title('Top Level')
# Global Padding pady and padx
pad_x = 0
pad_y = 0
# CASCADE MENU
# create a parent menu.
self.parentmenu1 = Menu(parent, tearoff=0)
#self.menubar1.add_command(label='Menu1', command=self.hello)
#create a child menu for parent menu.
self.parentmenu1_child1 = Menu(parent, tearoff=0)
self.parentmenu1_child1.add_command(label='Item1', command=self.hello)
self.parentmenu1_child1.add_command(label='Item2', command=self.hello)
self.parentmenu1_child1.add_command(label='Item3', command=self.hello)
#add child menu to parent menu.
self.parentmenu1.add_cascade(label='Menu1', menu=self.parentmenu1_child1)
#self.menubar1.add_separator()
# SINGLE MENU
# create a parent menu.
self.parentmenu1.add_command(label='Menu2', command=self.hello)
# SINGLE MENU
# create a parent menu.
self.parentmenu1.add_command(label='Menu3', command=self.hello)
# display the parent menu.
parent.config(menu=self.parentmenu1)
# Create controls
#create label
self.label1 = Label(parent, text='Label1')
#create textbox
self.textbox1 = Entry(parent)
#create button
self.button1 = Button(parent, text='Button1', command=self.hello)
#string variable to hold checkbox1 values.
self.str_checkbox1 = StringVar()
#create checkbox
self.checkbox1 = Checkbutton(parent, text='Checkbox1', variable=self.str_checkbox1, onvalue='on1', offvalue='off1')
#deselect checkbox1
self.checkbox1.deselect()
#string variable to hold checkbox2 values.
self.str_checkbox2 = StringVar()
#create checkbox
self.checkbox2 = Checkbutton(parent, text='Checkbox2', variable=self.str_checkbox2, onvalue='on2', offvalue='off2')
#deselect checkbox2
self.checkbox2.deselect()
#???? ..what sets the groupbox apart from others. primary key???!!
self.str_radiobutton1 = StringVar()
#command= parameter missing.
self.radiobutton1 = Radiobutton(parent, text='Radio 1', variable=self.str_radiobutton1, value='a')
self.radiobutton2 = Radiobutton(parent, text='Radio 2', variable=self.str_radiobutton1, value='b')
self.radiobutton1.select()
#create a list of options.
optionList = ('Option1', 'Option2', 'Option3')
#string variable to hold optionlist values.
self.str_optionmenu1 = StringVar()
#associate string variable with optionlist
self.str_optionmenu1.set(optionList[0])
#create optionmenu
self.optionmenu1 = OptionMenu(parent, self.str_optionmenu1, *optionList)
#create a frame
self.frame1 = Frame(parent)
#create a text.
self.textarea1 = Text(self.frame1, width=20, height=10)
#align text left and fill frame with it.
self.textarea1.pack(side=LEFT, fill=Y)
#create a scrollbar.
self.scrollbar1 = Scrollbar(self.frame1)
#align scrollbar right and fill frame with it.
self.scrollbar1.pack(side=RIGHT, fill=Y)
#what is going to be scrolled?
self.scrollbar1.config(command=self.textarea1.yview)
#set textarea scrollbar.
self.textarea1.config(yscrollcommand=self.scrollbar1.set)
#align frame left and fill.
self.frame1.pack(side=LEFT, fill=Y)
#create a frame
self.frame2 = Frame(parent)
#create a text.
self.listbox1 = Listbox(self.frame2, width=20, height=10, activestyle='none', selectmode=SINGLE)
#create a list of items.
optionList = ('Item1', 'Item2', 'Item3', 'Item4', 'Item5', 'Item6', 'Item7', 'Item8', 'Item9', 'Item10', 'Item11')
#add items from list to listbox
for item in optionList:
self.listbox1.insert(END, item)
#align text left and fill frame with it.
self.listbox1.pack(side=LEFT, fill=Y)
#create a scrollbar.
self.scrollbar2 = Scrollbar(self.frame2)
#align scrollbar right and fill frame with it.
self.scrollbar2.pack(side=RIGHT, fill=Y)
#what is going to be scrolled?
self.scrollbar2.config(command=self.listbox1.yview)
#set textarea scrollbar.
self.listbox1.config(yscrollcommand=self.scrollbar2.set)
#align frame left and fill.
self.frame2.pack(side=LEFT, fill=Y)
# Place controls inside of grid
self.label1.grid(row=0, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.textbox1.grid(row=0, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.button1.grid(row=1, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.checkbox1.grid(row=1, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.checkbox2.grid(row=1, column=2, padx=pad_x, pady=pad_y, sticky=W)
self.optionmenu1.grid(row=2, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.frame1.grid(row=2, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.radiobutton1.grid(row=3, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.radiobutton2.grid(row=3, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.frame2.grid(row=4, column=0, padx=pad_x, pady=pad_y, sticky=W)
if __name__ == '__main__':
parent = Tk()
app = Application(parent)
parent.mainloop()
Alright. Apparently tkMessageBox has been renamed to messagebox in Python 3.x. Also this
module is not available in tkinter so even though a developer might use:
from tkinter import *
..he/she would still need to:
from tkinter import messagebox

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