i've just started learning tkinter for python, and i'm trying to get the button to change its text when it's clicked on.
this seems like a very simple question, but i can't find any answers. the code i'm using at the moment doesn't work - when the window opens, it displays 'clicked!' as a label above the button immediately, before i've clicked on the button.
from tkinter import *
root = Tk()
def click():
label = Label(root, text = 'clicked!')
label.pack()
button = Button(root, text='click me', command = click())
button.pack()
root.mainloop()
To change an existing button's text (or some other option), you can call its config() method and pass it keyword arguments with new values in them. Note that when constructing the Button only pass it the name of the callback function — i.e. don't call it).
from tkinter import *
root = Tk()
def click():
button.config(text='clicked!')
button = Button(root, text='click me', command=click)
button.pack()
root.mainloop()
You're passing command = click() to the Button constructor. This way, Python executes click, then passes its return value to Button. To pass the function itself, remove the parentheses - command = click.
Related
Is there a simple way to get the right click menu to open on texty only and not the whole window?
This was a quick mashup to illustrate my question. Inheriting from texty on line 25 was a shot in the dark, which didnt work, but it's close to a simple solution, like I am seeking. I was hoping to avoid programming a whole class each time I want to set a right click menu.
from tkinter import *
from tkinter import ttk
def menu_popup(event):
try:
popup.tk_popup(event.x_root, event.y_root, 0)
finally:
popup.grab_release()
win = Tk()
win.geometry("600x550+125+125")
e = Entry(win, width=50, font=('Helvetica', 11))
e.pack()
e.insert(0, "Some text....")
label = Label(win, text="Right-click to see a menu", font= ('Helvetica 18'))
label.pack(pady= 40)
texty=Text(win, height=10)
texty.pack()
popup = Menu(texty, tearoff=0)
popup.add_command(label="New")
popup.add_separator()
popup.add_command(label="Open")
popup.add_separator()
popup.add_command(label="Close")
win.bind("<Button-3>", menu_popup)
button = ttk.Button(win, text="Quit", command=win.destroy)
button.pack()
mainloop()
The widget on which the callback should be executed for the respective event is determined by the widget you call bind on(and the level of bind too*). So if you want the event to be identified within texty, then apply binding to it.
texty.bind("<Button-3>", menu_popup)
* There is bind_all which executes no matter which widget has focus or is called upon. Read 54.1. Levels of binding for more info.
Use the Python Tkinter , create a sub-panel (TopLevel) to show something and get user input, after user inputed, clicked the "EXIT" found the whole GUI (main panel) also destory.
How to only close the toplevel window?
from tkinter import *
lay=[]
root = Tk()
root.geometry('300x400+100+50')
def exit_btn():
top = lay[0]
top.quit()
top.destroy()
def create():
top = Toplevel()
lay.append(top)
top.title("Main Panel")
top.geometry('500x500+100+450')
msg = Message(top, text="Show on Sub-panel",width=100)
msg.pack()
btn = Button(top,text='EXIT',command=exit_btn)
btn.pack()
Button(root, text="Click me,Create a sub-panel", command=create).pack()
mainloop()
This seemed to work for me:
from tkinter import *
lay=[]
root = Tk()
root.geometry('300x400+100+50')
def create():
top = Toplevel()
lay.append(top)
top.title("Main Panel")
top.geometry('500x500+100+450')
msg = Message(top, text="Show on Sub-panel",width=100)
msg.pack()
def exit_btn():
top.destroy()
top.update()
btn = Button(top,text='EXIT',command=exit_btn)
btn.pack()
Button(root, text="Click me,Create a sub-panel", command=create).pack()
mainloop()
Your only mistake is that you're calling top.quit() in addition to calling top.destroy(). You just need to call top.destroy(). top.quit() will kill mainloop, causing the program to exit.
You can't close to root window. When you will close root window, it is close all window. Because all sub window connected to root window.
You can do hide root window.
Hide method name is withdraw(), you can use show method for deiconify()
# Hide/Unvisible
root.withdraw()
# Show/Visible
root.deiconify()
you can use lambda function with the command it's better than the normal function for your work
ex)
btn = Button(top,text='EXIT',command=exit_btn)
change the exit_btn to lambda :top.destroy()
In my case, I passed a callback function from the parent class, and once the submit button is clicked it will the callback function passing the return values.
The callback function will call the destroy method on the top-level object, thus in that way you'll close the frame and have the return value.
I have following python code in Tkinter.
import tkinter as tk
def main_gui(login, s):
login.quit() # close login window
win = tk.Tk()
win.geometry('300x150')
name = tk.Label(win, text='Hello' + s.get()) # Hello David
name.pack()
win.mainloop()
# initial Tkinter frame
login = tk.Tk()
login.title('Login')
login.geometry('300x150')
# input user name
user_name_var = tk.StringVar()
user_name_var.set('David')
tk.Label(login, text='User name').place(x=10, y=50)
user_name = tk.Entry(login, textvariable=user_name_var)
user_name.place(x=100, y=50)
input_ok = tk.Button(win_login, command=lambda: main_gui(login, user_name), text='OK', width=15)
input_ok.place(x=100, y=90)
win_login.mainloop()
I want to close login window, but my code can not close it. How to solve it.
You are almost there - only two details you have to adapt:
The method to remove a widget in Tkinter is destroy, so login.quit() should be login.destroy().
Once login is destroyed, the user_name Entry will also be destroyed, and you will not be able to get the name from it anymore. You should get the name earlier, e.g., directly in the lambda:
... lambda: main_gui(login, user_name.get()), ...
you can use the
root.withdraw()
function, this will close the window without completely destroying all of the root.after functions
The code below shows part of my program and the issue im facing.
def checkAnswer():
mainAnswer = answer01.get()
if len(mainAnswer) == 0:
messagebox.showwarning(message='Please answer the question!')
return
if int(mainAnswer) != answer:
messagebox.showwarning(message='Incorrect! The correct answer is: ' + str(answer))
else:
nxtquest.config(state=NORMAL)
messagebox.showinfo(message='Correct! :)')question01 = Label(easy)
question01.grid(row=2, column=0)
answer01 = Entry(easy)
answer01.grid(row=3, column=2)
answer01.bind('<Return>', func=lambda e:checkAnswer())
start = Button(easy, text = "Start!", command=ask, bg='green', fg='white')
start.grid(row=3, column=3)
nxtquest = Button(easy, text='Next Question', command=ask)
nxtquest.grid(row=5, column=2)
checkbut = Button(easy, text='Check', command=checkAnswer)
checkbut.grid(row=4, column=2)
#check button and answer01 enabled after start pressed
launch = 1
if launch == 1:
answer01.config(state=DISABLED)
checkbut.config(state=DISABLED)
nxtquest.config(state=DISABLED)
The issue which im struggling here is that whenever i run the program everything is okay. When the window is displayed checkbut, nxtquest and label answer01 are greyed out (disabled).
The start button enables only checkbut and answer01 and then is destroyed. (So far so good)
So nxtquest will enable once the input is correct as seen in the
else:
nxtquest.config(state=NORMAL)
But when I reach another question the nxtquest button is already enabled, this is the problem!
How could I make it so the button will enable itself only after the warning message box is displayed?
Could I ask for some help with this and possibly suggestions if you see any rookie mistakes ?
Whilst I don't know of any way you could do this with a messagebox widget (although I'm sure there's an event you could use as the trigger) you can most certainly do this by substituting the messagebox with a Toplevel widget and using .protocol("WM_DELETE_WINDOW", callback()) on the widget.
This would mean that whenever the Toplevel widget was "closed" we would actually be overwriting the action taken when the event was raised and would manually handle the closing of the widget as well as whatever else we wanted it to do.
This would look something like the below:
from tkinter import *
root = Tk()
button = Button(root, text="Ok", state="disabled")
button.pack()
top = Toplevel(root)
def close():
top.destroy()
button.configure(state="active")
top.protocol("WM_DELETE_WINDOW", close)
root.mainloop()
If you close the Toplevel widget you will see that the button is now active instead. This would equally work if we added a Button to the Toplevel widget which called the function close().
from Tkinter import *
import webbrowser
root = Tk()
frame = Frame(root)
frame.pack()
url = 'http://www.sampleurl.com'
def OpenUrl(url):
webbrowser.open_new(url)
button = Button(frame, text="CLICK", command=OpenUrl(url))
button.pack()
root.mainloop()
My goal is to open a URL when I click the button in the GUI widget. However, I am not sure how to do this.
Python opens two new windows when I run the script without clicking
anything. Additionally, nothing happens when I click the button.
You should use
button = Button(root, text="CLCK", command=lambda aurl=url:OpenUrl(aurl))
this is the correct way of sending a callback when arguments are required.
From here:
A common beginner’s mistake is to call the callback function when
constructing the widget. That is, instead of giving just the
function’s name (e.g. “callback”), the programmer adds parentheses and
argument values to the function:
If you do this, Python will call the callback function before creating
the widget, and pass the function’s return value to Tkinter. Tkinter
then attempts to convert the return value to a string, and tells Tk to
call a function with that name when the button is activated. This is
probably not what you wanted.
For simple cases like this, you can use a lambda expression as a link
between Tkinter and the callback function:
Alternatively, you don't have to pass the URL as an argument of the command. Obviously your OpenUrl method would be stuck opening that one URL in this case, but it would work.
from Tkinter import *
import webbrowser
url = 'http://www.sampleurl.com'
root = Tk()
frame = Frame(root)
frame.pack()
def OpenUrl():
webbrowser.open_new(url)
button = Button(frame, text="CLICK", command=OpenUrl)
button.pack()
root.mainloop()