Working on a unit converter using Tkinter python, I want to change all other units according to the input unit but can't able to call that function which later configures other labels of units.
mainEntry = Entry(width=15,font="arial 15 bold")
mainEntry.grid(row=0,column=0)
This Entry will get the input from user and other labels get update according to input without clicking any button.
Set a variable to Entry widget and use the trace method to detect any changes in the text and update labels accordingly.
Here is an example:
from tkinter import *
def change_lbl(*args):
lbl['text']=var.get()
root = Tk()
var = StringVar()
var.trace('w', change_lbl)
lbl = Label(root, text='Hello')
lbl.pack()
entry = Entry(root, textvariable=var)
entry.pack()
root.mainloop()
Related
I am new to tkinter application. The below code is working fine. Please help how to implement mentioned features.
The dynamic value should be displayed above clear button or below the combo box ( Used pack is bottom )- Now working
Clear the label value on combo box selection.
import tkinter as tk
from tkinter import ttk
from tkinter import *
from datetime import datetime
# root window
root = tk.Tk()
root.geometry("500x350")
root.resizable(False, False)
root.title('Test')
# Log Generator in frame
Generator = tk.Frame(root)
Generator.pack(padx=10, pady=10, fill='x', expand=True)
def clear():
combo.set('')
# Function to print the index of selected option
# in Combobox
def get_log_file_name(*arg):
date_Value = datetime.now().strftime("%Y_%m_%d_%I%M%S")
output_file_name_value = "Log_"+date_Value
if var.get() == "apple":
Label(Generator, text="The value at index: "+output_file_name_value+".txt", font=('Helvetica 12')).pack()
else:
Label(Generator, text="The value at index: "+output_file_name_value+".html", font=('Helvetica 12')).pack()
# Define Tuple of months
months = ('apple','banana')
# Create a Combobox widget
label = ttk.Label(Generator, text="Selection_Option:",font=('Helvetica', 10, 'bold'))
label.pack(fill='x', expand=True)
var = StringVar()
combo = ttk.Combobox(Generator, textvariable=var)
combo['values'] = months
combo['state'] = 'readonly'
combo.pack(padx=5, pady=5)
# Set the tracing for the given variable
var.trace('w', get_log_file_name)
# Create a button to clear the selected combobox
# text value
button = Button(Generator, text="Clear", command=clear)
button.pack(side=left)
# Make infinite loop for displaying app on
# the screen
Generator.mainloop()
Clear the label value on combo box selection.
You need to capture the ComboboxSelect event to do that and the function to execute if captured
the function should be like this
What you want to do here, is to capture the combobox event, and then, do the label configuration when capturing it,
Below is the code to do the thing. and you can add code there.
def comboboxEventCapture(e=None):
label.configure(text='')
# Your code after resetting variables!
Here's the event capturing part
combo.bind("<<ComboboxSelect>>", comboboxEventCapture)
You can name the function whatever you want though.
Note that the arguement e is needed because if the event is captured, the event itself is passed as a parameter into the function, that is of no use here (unless you are going to do something with it, then use e.objname)
The dynamic value should be displayed above clear button
The second label could be outside of get_log_file_name() function.
And also configure inside function. So you don't do duplicate Label widget, naming Label2
Also the pack() must be split to prevent an error.
To clear Label2 use .configure(text='')
We will be using ttk. So don't do this from tkinter import *
Code:
import tkinter as tk
from tkinter import ttk
from datetime import datetime
root = tk.Tk()
root.geometry("500x350")
root.resizable(False, False)
root.title('Test')
Generator = tk.Frame(root)
Generator.pack(padx=10, pady=10, fill='x', expand=True)
def clear():
label2.configure(text='')
def get_log_file_name(*arg):
date_Value = datetime.now().strftime("%Y_%m_%d_%I%M%S")
output_file_name_value = "Log_"+date_Value
if var.get() == "apple":
label2.configure(text="The value at index: "+output_file_name_value+".txt", font=('Helvetica 12'))
else:
label2.configure(text="The value at index: "+output_file_name_value+".html", font=('Helvetica 12'))
# Define Tuple of months
months = ('apple','banana')
# Create a Combobox widget
label2 = ttk.Label(Generator)
label2.pack()
label = ttk.Label(Generator, text="Selection_Option:",font=('Helvetica', 10, 'bold'))
label.pack(fill='x', expand=True)
var = tk.StringVar()
combo = ttk.Combobox(Generator, textvariable=var)
combo['values'] = months
combo['state'] = 'readonly'
combo.pack(padx=5, pady=5)
# Set the tracing for the given variable
var.trace('w', get_log_file_name)
# Create a button to clear the selected combobox
# text value
button = ttk.Button(Generator, text="Clear", command=clear)
button.pack(side='left')
# Make infinite loop for displaying app on
# the screen
Generator.mainloop()
Screenshot for apple:
Screenshot for banana:
Screenshot to clear Label2:
I want to use the input value as variable and this is my code.
from tkinter import *
from tkinter import messagebox
window = Tk()
Label(window, text='Cavity number').grid(row=0)
CavNum = StringVar()
for i in range(1,8) :
globals()['L{}_CavNum'.format(i)] = StringVar()
globals()['L{}_CavNum'.format(i)] = Entry(window, textvariable=globals()['L{}_CavNum'.format(i)])
globals()['L{}_CavNum'.format(i)].grid(row=0, column=i)
window.geometry("1200x150")
window.mainloop()
everytime I do print(L1_CavNum), it says "<tkinter.Entry object .!entry>". please tell me what is the problem
You are re-using the same name for the entry widget as you use for StringVar. You could simply change globals()['L{}_CavNum'.format(i)] = StringVar() to globals()['L{}_CavNumSV'.format(i)] = StringVar() and print(L1_CavNum) to print(L1_CavNumSV.get()). However the .get() function will execute when your code runs so you will have to have a button or another event to callback the function.
I would do it like this.
from tkinter import *
def print_vars():
for x in range(len(cavity_string_vars)):
print(cavity_string_vars[x].get())
window = Tk()
Label(window, text='Cavity number').grid(row=0)
cavity_string_vars = []
cavity_entries = []
for i in range(7):
cavity_string_vars.append(StringVar())
cavity_entries.append(Entry(window, textvariable=cavity_string_vars[i]))
cavity_entries[i].grid(row=0, column=i)
print_button = Button(window, text="Print", command=print_vars)
print_button.grid(row=1, column=0)
window.geometry("1200x150")
window.mainloop()
To me associated arrays are much easier than naming each variable even when you program it as you have. Perhaps that is needed for your case.
This is my first attempt at a GUI. Right now I just want to be able to click a radiobutton and make it print the value I assigned to the button. However, var.get() isn't giving me anything. I tried it with IntVar (and had my values as 1 and 2 instead of "proton" and "electron") and var.get() would just give me 0. With StringVar it gives nothing (nothing prints when choosecharge is called by the radiobutton). I've tried reading stuff about radiobuttons and I wrote my code based on how I saw it done and it successfully creates the radiobuttons, but the whole point is to be able to use their values when clicked.
import tkinter as tk
def choosecharge():
print(var.get())
root = tk.Tk()
var = tk.StringVar()
proton = tk.Radiobutton(root, text = "proton", variable = var, value = "proton", command = choosecharge)
proton.pack( )
electron = tk.Radiobutton(root, text="electron", variable = var, value= "electron", command = choosecharge)
electron.pack( )
root.mainloop()
I have taken a slightly different approach to accomplish this task.
I created a dictionary of the integer radiobutton values as key and
the string that you wish to print as value.
Used a label widget to print the string in the GUI
import tkinter as tk
root = tk.Tk()
# define an IntVar
var = tk.IntVar()
# create a dictionary of key:value pair as radiobutton_value: str_name_to_print
values = {1: "proton", 2: "electron"}
# instantiate a label widget
lbl = tk.Label(root)
def choosecharge():
# update the label widgets using the dictionary
lbl.config(text=values[var.get()])
proton = tk.Radiobutton(root, text="proton", variable=var, value=1, command=choosecharge)
proton.pack(anchor=tk.W)
electron = tk.Radiobutton(root, text="electron", variable=var, value=2, command=choosecharge)
electron.pack(anchor=tk.W)
# pack the label widget below the two radiobuttons
lbl.pack()
root.mainloop()
Screenshot
I have commented the lines in the code for better understanding. I hope this solution helps you.
I want to update the label of a Tkinter LabelFrame widget.
For a Label widget, this can be done using the textvariable attribute, to which one can assign a StringVar.
I want to do the same thing, but for a LabelFrame
self.labelText = StringVar()
self.selectionFrame = ttk.LabelFrame(self, textvariable=self.labelText)
(...)
if A:
self.labelText.set("LabelA")
elif B:
self.labelText.set("LabelB")
How can I achieve this?
You can't. Neither the Tkinter LabelFrame nor the ttk LabelFrame support associating a variable with the widget.
If what you're really asking is how can you change the label, then you can use the configure method:
self.selectionFrame.configure(text="hello")
I just found some kind of a solution - using the labelwidget attribute to supply a separate Label object which uses the underlying StringVar:
self.labelText = StringVar()
self.labelWidget = Label(self, textvariable=self.labelText)
self.selectionFrame = ttk.LabelFrame(self, labelwidget=self.labelWidget)
This way, I can update the labelText to change the label of the LabelFrame
self.labelText.set("New Label")
I found that there is a problem to set a new label text due to text length.
So, I recommend that define a width of labelwidget as mentioned below:
self.labelWidget = Label(self, textvariable=self.labelText, width = 20)
I've been trying to develop a small gui to calculate some totals with weighting etc. While trying to get a total to update real-time with a changing entry, I noticed it took two events to update; This is a simplified version of my code that shows the problem:
from Tkinter import *
root=Tk()
frame=Frame(root)
frame.pack()
entry=Entry(frame)
entry.pack()
label=Label(frame,text="entry:")
label.pack()
def updatelabel(event):
label=Label(frame,text="entry:"+entry.get())
label.pack()
print "called"
entry.bind("<Key>", updatelabel)
root.mainloop()
When you input into the field the function calls, but does not update to what was typed until the next character is typed. How would I go about getting the label to update to what is in the field at the time?
You don't really need to explicitly process events and use callback functions to accomplish what you want. In other words it's possible to get Tkinter to do it for you automatically using a StringVar().
from Tkinter import *
root=Tk()
frame=Frame(root)
frame.pack()
entry_var = StringVar()
entry_var.set('')
entry = Entry(frame, textvariable=entry_var)
entry.pack()
label = Label(frame, text='entry: ')
label.pack(side=LEFT)
contents = Label(frame, textvariable=entry_var)
contents.pack(side=LEFT)
entry.focus_set() # force initial keyboard focus to be on entry widget
root.mainloop()
Instead of using entry.bind("<Key>", update label), I used the root window instead: root.bind("<Key>", update label). This did the trick, however it is important to realize that the function updatelabel() will be called every time a key is pressed in your tkinter window. This could cause some problems if you have more than one entry box updating labels.
Here is the code I wrote with a few modifications:
from Tkinter import *
root=Tk()
frame=Frame(root)
frame.pack()
update_label = StringVar() # Made a StringVar so you don't get new labels every time a key is pressed.
update_label.set("entry:")
entry=Entry(frame)
entry.pack()
label=Label(frame,textvariable=update_label) # Used textvariable= instead of text=
label.pack()
def updatelabel(event):
update_label.set("entry:" + entry.get()) # Setting the variable used in textvariable=
print "called"
root.bind("<Key>", updatelabel) # Changed entry.bind to root.bind
root.mainloop()
No it doesn't require two entries to be called, it is called on the first entry. The key bindings are on the Entry widgets to avoid the problems that a binding to the root will create if you have more than one entry widget.
import tkinter as tk
class SmallApp(tk.Frame):
def __init__(self, master = None):
tk.Frame.__init__(self, master)
self.master = master
self.pack()
self.entry = tk.Entry(self)
self.entry.pack()
self.var = "entry:"
self.label = tk.Label(text = self.var)
self.label.pack()
self.entry.bind("<Key>", self.updatelabel)
def updatelabel(self, event):
self.var += event.char
self.label.configure(text=self.var)
root = tk.Tk()
app = SmallApp(root)
app.mainloop()