I'm trying to get a set of buttons that will change the value of my global variable "y". I'm pretty new to python, and am very new to tkinter. I have tried using lambda and solutions in similar questions haven't seemed to fix the issue.
Here is my code:
import tkinter as tk
from tkinter import *
master=Tk()
def assignint(value):
global y
y = value
y= StringVar()
frame = Frame(master)
frame.grid(row=0, columnspan=4)
for i in range(2):
Grid.rowconfigure(master,i,weight=1)
for i in range(4):
Grid.columnconfigure(master,i,weight=1)
Button1 = Button(master,text='Fault1',command= lambda: assignint(0))
Button1.grid(row=1, column=0,sticky=N+S+E+W)
Button2 = Button(master,text='Fault2',command= lambda: assignint(1))
Button2.grid(row=1, column=1,sticky=N+S+E+W)
Button3 = Button(master,text='Fault3',command= lambda: assignint(2))
Button3.grid(row=1, column=2,sticky=N+S+E+W)
Button4= Button(master,text='Fault4',command= lambda: assignint(3))
Button4.grid(row=1, column=3,sticky=N+S+E+W)
if y.get()!='':
print('The value of y is:', y.get())
mainloop()
You need to use set method when changing a StringVar's value.
as in replace:
y = value
with:
y.set(value)
Related
This question already has an answer here:
Tkinter assign button command in a for loop with lambda [duplicate]
(1 answer)
Closed 1 year ago.
I'm trying to make a little file explorer with just buttons, I'm still in the early stages and want to make a function prints which button was pressed and came up with this:
import tkinter as tk
buttons = []
window = tk.Tk()
window.geometry("200x100")
def open(button):
print(button)
def list(titles):
i=0
while i<(len(titles)):
btn = tk.Button(text=titles[i], width=20, command=lambda: open(i))
buttons.append(btn)
buttons[i].grid(row=i, column=1)
print(f"adding {titles[i]}")
i=i+1
list(["title1", "title2", "title3"])
window.mainloop()
There's one problem: It always prints 3. I think I know what the problem is, i always stays 3 after generating the button so it passes 3 to the function, but I don't know how to solve it.
I used the lambda cuz I cant pass parameters just using open(i) and found the lambda-solution to that on this question .
Can someone help?
Tnx!
Because it over writes the commands on one button when you assign it again. Do:
import tkinter as tk
buttons = []
window = tk.Tk()
window.geometry("200x100")
def open(button):
print(button)
def list(titles):
btn = tk.Button(text=titles[0], width=20, command=lambda: open(1))
buttons.append(btn)
buttons[0].grid(row=1, column=1)
print(f"adding {titles[0]}")
btn = tk.Button(text=titles[1], width=20, command=lambda: open(2))
buttons.append(btn)
buttons[1].grid(row=2, column=1)
print(f"adding {titles[1]}")
btn = tk.Button(text=titles[2], width=20, command=lambda: open(2))
buttons.append(btn)
buttons[2].grid(row=3, column=1)
print(f"adding {titles[2]}")
list(["title1", "title2", "title3"])
window.mainloop()
i am developing an application to calculate some taxes and show the result in the graphical interface. The code itself works perfectly, but if i use numbers with bigger squares, the result overlaps over the previous one. My question is, is it possible to clear the previous result and calculate the new one?
Follow the complete code below:
from tkinter import *
root = Tk()
l_vlrRec = Label(root, text='Receita')
l_vlrRec.place(x=10, y=10)
e_vlrRec = Entry(root)
e_vlrRec.place(x=75, y=10, width=75)
def calcular():
receita = float(e_vlrRec.get())
l_result = Label(root, text='{:.2f}'.format(receita))
l_result.place(x=10, y=150)
e_vlrRec.delete(0, END)
bt = Button(root, text='Calcular', command=calcular)
bt.place(x=10, y=50)
root.mainloop()
You can use the label's textvariable and also you don't have to instantiate a new Label every time the button is pressed:
v_result = DoubleVar()
l_result = Label(root, textvariable=v_result)
l_result.place(x=10, y=150)
def calcular():
v_result.set(round(float(e_vlrRec.get()),2))
You can do the same for your Entry object e_vlrRec so you don't have to cast the string you get by calling e_vlrRec.get() but use the variable's get() instead
Without using textvariable you can also reconfigure the label's text parameter:
l_result.configure(text='{:.2f}'.format(receita))
or
l_result['text'] = '{:.2f}'.format(receita)
I'm new to trying out python GUI's and tried tkinter and pyglet, but only through tutorials, in-order-to understand the basic classes and functions. But what I'm currently trying to do is to get a button to increase a number whilst displaying that number at the same time. Somehow, even though the variable number was stated globally as 0, the function to increase it doesn't do anything, it actually produces an error: 'UnboundLocalError: local variable 'number' referenced before assignment'. I have no idea how to correct this.
The tutorials I've seen on both YouTube and as an article, don't talk about how to do this exactly. The article does mention how to change a certain text though, but not a previously created variable (which in my case would be 'number').
from tkinter import *
number = 0
window = Tk()
window.title("Programme")
window.geometry('350x250')
label = Label(window, text=number)
label.grid(column=0,row=0)
def clicked():
number += 1
button = Button(window, text="Push Me", command=clicked)
button.grid(column=1, row=2)
window.mainloop()
Is there any way to do this?
Also I've been looking for how to add time, to handle events and such, through ticks. But everything I find on the internet is about literally displaying a clock on the GUI, which is useless, or at least I don't know how to use it to have a ticking function.
You need to increment the number, like you do, but also update the Label to display the new number:
from tkinter import *
number = 0
window = Tk()
window.title("Programme")
window.geometry('350x250')
label = Label(window, text=number)
label.grid(column=0,row=0)
def clicked():
global number
number += 1
label.config(text=number)
button = Button(window, text="Push Me", command=clicked)
button.grid(column=1, row=2)
window.mainloop()
An easier way to do this is to use tkinter's version of an integer: IntVar. It takes care of the Label updates automatically, but it requires you use get() and set() to work with it.
from tkinter import *
def clicked():
number.set(number.get()+1)
window = Tk()
window.title("Programme")
window.geometry('350x250')
number = IntVar()
label = Label(window, textvariable=number)
label.grid(column=0,row=0)
button = Button(window, text="Push Me", command=clicked)
button.grid(column=1, row=2)
window.mainloop()
Here is my entire code:
from tkinter import *
def up():
number.set(number.get()+1)
def down():
number.set(number.get()-1)
window = Tk()
window.title("Programme")
window.geometry('350x250')
number = IntVar()
frame = Frame(window)
frame.pack()
entry = Entry(frame, textvariable=number, justify='center')
entry.pack(side=LEFT, ipadx=15)
buttonframe = Frame(entry)
buttonframe.pack(side=RIGHT)
buttonup = Button(buttonframe, text="▲", font="none 5", command=up)
buttonup.pack(side=TOP)
buttondown = Button(buttonframe, text="▼", font="none 5", command=down)
buttondown.pack(side=BOTTOM)
window.mainloop()
It looks better for me when the buttons are inside of the entry widget directly.
I got example code were there are two windows and in the second one there's a tick box that doesn't change value when it is ticked. How can I fix this? I tried returning the value of the tickbox however that failed as well.
from tkinter import *
root = Tk()
def open_custom_gui():
custom_gui()
b = Button(root,command=open_custom_gui)
b.grid(row=1,column=0)
def custom_gui():
def getinfo():
print(var1.get())
custom= Tk()
var1 = IntVar()
tickbox_1 = Checkbutton(custom,text='TEST',variable=var1,)
tickbox_1.grid(row=0,column=0)
b = Button(custom,command=getinfo)
b.grid(row=1,column=0)
custom.mainloop()
root.mainloop()
The problem has something to do with calling Tk() twice. You can fix that by explicitly creating a second Toplevel window.
from tkinter import *
root = Tk()
def open_custom_gui():
custom_gui()
b = Button(root, command=open_custom_gui)
b.grid(row=1, column=0)
def custom_gui():
def getinfo():
print(var1.get())
custom = Toplevel() # CHANGE THIS (don't call Tk() again)
var1 = IntVar()
tickbox_1 = Checkbutton(custom, text='TEST', variable=var1)
tickbox_1.grid(row=0, column=0)
b = Button(custom, command=getinfo)
b.grid(row=1, column=0)
custom.mainloop()
root.mainloop()
Alternatively you can also fix it by specifying the second Tk instance when you create the IntVar tkinter variable:
def custom_gui():
def getinfo():
print(var1.get())
custom = Tk()
var1 = IntVar(master=custom) # ADD a "master" keyword argument
tickbox_1 = Checkbutton(custom, text='TEST', variable=var1)
tickbox_1.grid(row=0, column=0)
b = Button(custom, command=getinfo)
b.grid(row=1, column=0)
custom.mainloop()
However I would suggest using the first approach because the documentation says the following (about adding the argument to the IntVar constructor):
The constructor argument is only relevant if you’re running Tkinter with
multiple Tk instances (which you shouldn’t do, unless you really know what
you’re doing).
I know that there are a lot of questions dealing with tkinter but I have looked at a bunch of them and none of them seem to help me.
import tkinter
class Calculator:
def __init__(self):
window = tkinter.Tk()
window.geometry("200x300")
window.title("Calculator")
lbl = tkinter.Label(window, text="placeholder", bg="blue", textvariable="labelText")
lbl.grid(row=0, column=0, columnspan=3)
self.firstNumArray = []
self.secondNumArray = []
self.operation = ""
self.currentNum = "first"
def appendNumber(self, number):
print("Appending Number")
if self.currentNum == "first":
self.firstNumArray.append(number)
print("".join(str(x) for x in self.firstNumArray))
lbl.config(text="".join(str(x) for x in self.firstNumArray))
window.update()
else:
self.secondNumArray.append(number)
for i in range(1,4):
string = "Creating button at ({0},{1})".format(0,i)
print(string)
button = tkinter.Button(text=i, command=lambda: appendNumber(self, i))
button.grid(row=1, column=i-1)
for i in range(1,4):
string = "Creating button at ({0},{1})".format(1,i)
print(string)
button = tkinter.Button(text=i+3, command=lambda: appendNumber(self, i+3))
button.grid(row=2, column=i-1)
for i in range(1,4):
string = "Creating button at ({0},{1})".format(2,i)
print(string)
button = tkinter.Button(text=i+6, command=lambda: appendNumber(self, i+6))
button.grid(row=3, column=i-1)
div = tkinter.Button(text="/")
mult = tkinter.Button(text="*")
add = tkinter.Button(text="+")
sub = tkinter.Button(text="-")
add.grid(row=1, column=3)
sub.grid(row=2, column=3)
mult.grid(row=3, column=3)
div.grid(row=4, column=3)
button = tkinter.Button(text="0")
button.grid(row=4, column=1)
window.mainloop()
calc = Calculator()
When I launch the program the window opens. When I click on a button the text in the label does not change. I have tried using a StringVar as the textvariable and then calling the set() function, but that did not work either. I think it has to do with the scope of the function. I had to place the appendNumber() function inside the __init__() because for some reason self.lbl = tkinter.Label() makes nothing pop up at all.
There are a few problems with your code.
labelText should, of course, be a StringVar and not a string...
labelText = tkinter.StringVar()
lbl = tkinter.Label(window, bg="blue", textvariable=labelText)
lbl.grid(row=0, column=0, columnspan=3)
Now you can use labelText.set to update the text. Also, no need for self parameter or window.update
def appendNumber(number):
if self.currentNum == "first":
self.firstNumArray.append(number)
labelText.set("".join(str(x) for x in self.firstNumArray))
else:
self.secondNumArray.append(number)
You can put all the buttons in one loop using // (integer (!) division) and % (modulo) operations. Also, be aware that the variable in the lambda is evaluated when the function is called, not when it is declared, i.e. all the lambdas will use the last value of i (9 in this case) -- see e.g. here. As a remedy, use lambda n=i+1: appendNumber(n).
for i in range(9):
btn = tkinter.Button(text=i+1, command=lambda n=i+1: appendNumber(n))
btn.grid(row=i//3+1, column=i%3)
Not really a problem, but since you don't need a reference to those buttons, you can make your code a bit more compact (same for the others):
tkinter.Button(text="/").grid(row=1, column=3)