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Why is my Button's command executed immediately when I create the Button, and not when I click it? [duplicate]
(5 answers)
Closed last year.
I wanted to make button in tkinter, but when I started program, the command always calls when code just starts.
Here is example code:
import tkinter as tk
from tkinter import messagebox
window = tk.Tk()
window.title("Why this don't works???")
window.wm_geometry("100x100")
def message():
messagebox.showinfo("Hi there")
button = tk.Button(text="Hello", command=message())
button.grid(column=0, row=0)
while True:
window.update()
And then, button didn't worked. (When you press it, it don't works.)
I don't know what I'm doing wrong, so I need help.
The command should be a pointer to a function
In the code you wrote, the command gets the return value from the function.
command=message()
The correct way is
command = message
The problem is you are requesting a return value from the fucnction. Try using this.
from tkinter import *
# import messagebox from tkinter module
import tkinter.messagebox
# create a tkinter root window
root = tkinter.Tk()
# root window title and dimension
root.title("When you press a button the message will pop up")
root.geometry('75x50')
# Create a messagebox showinfo
def onClick():
tkinter.messagebox.showinfo("Hello World!.", "Hi I'm your message")
# Create a Button
button = Button(root, text="Click Me", command=onClick, height=5, width=10)
# Set the position of button on the top of window.
button.pack(side='top')
root.mainloop()
You have 2 errors:
first:
It must be command=message
second:
You must give a message argument too, you entered a title only.
Or, what you can do is.
Add another variable.
command = message()
Before this line,
button = tk.Button(text="Hello", command=message())
And chande this line to,
button = tk.Button(text="Hello", command=command)
I'm trying to open a Toplevel window with tkinter, from a system tray menu.
from cmath import phase
from tkinter import *
from tkinter import messagebox, messagebox
from tracemalloc import start
from pystray import MenuItem as item
import pystray
from PIL import ImageTk,Image
import pickle
def quit_window(icon, item):
icon.stop()
root.destroy()
exit()
def hidden():
global my_img1
top=Toplevel()
top.title("Secret menu, shhh :^)")
top.overrideredirect(True)
top.attributes('-alpha', 0.9)
w = 1100
h = 450
ws = top.winfo_screenwidth()
hs = top.winfo_screenheight()
x = (ws/2) - (w/2)
y = (hs/3) - (h/2)
top.geometry('%dx%d+%d+%d' % (w, h, x, y))
top.iconbitmap('screen.ico')
my_img1 = ImageTk.PhotoImage(Image.open("ITEXTRA.png"))
label1=Label(top,image=my_img1).place(relx=0.01,rely=0.01)
button2=Button(top,text="Close window",bg='#ff4a65',command=top.destroy, relief=GROOVE).place(relx=0.9,rely=0.9)
# Marks window as used
hiddenwindow=1
pickle.dump(hiddenwindow, open("window.dat", "wb"))
Button(root, text="Developer Options", padx=57, bg="#86b3b3",fg="black", command = hidden).grid(row=3,column=0)
def hide_window():
root.withdraw()
image=Image.open("screen.ico")
menu=(item('Dev window', hidden),item('show window', show_window),item('Exit app', quit_window))
icon=pystray.Icon("ITExtra", image, "Program", menu)
icon.run()
def show_window(icon, item):
icon.stop()
root.after(0,root.deiconify())
root.after(0,root.focus_force)
root = Tk()
root.title("ITextra")
root.geometry("400x400")
root.protocol('WM_DELETE_WINDOW', hide_window)
hidden()
root.mainloop()
But this unfortunately will not work, it won't pull up the toplevel window, nor the main one.
If I then open the root window myself, the toplevel window will open, but be unresponsive.
EDIT
Alright, so I tried adding the topwindow as class, but I keep getting error 'Top' object has no attribute 'tk'.
I pasted the updated code below. Any help is always greatly appreciated!
from cmath import phase
from tkinter import *
from tkinter import messagebox, messagebox
from tracemalloc import start
from pystray import MenuItem as item
import pystray
from PIL import ImageTk,Image
import pickle
class Top():
def __init__(self,master=None):
self.hide = True
def hidden(self):
if self.hide:
global my_img1
self.top=Toplevel(root)
self.top.title("Secret menu, shhh :^)")
self.top.attributes('-alpha', 0.9)
w = 1100
h = 450
ws = self.top.winfo_screenwidth()
hs = self.top.winfo_screenheight()
x = (ws/2) - (w/2)
y = (hs/3) - (h/2)
self.top.geometry('%dx%d+%d+%d' % (w, h, x, y))
self.top.iconbitmap('screen.ico')
my_img1 = ImageTk.PhotoImage(Image.open("ITEXTRA.png"))
label1=Label(self.top,image=my_img1).place(relx=0.01,rely=0.01)
button2=Button(self.top,text="Close window",bg='#ff4a65',command=self.top.destroy, relief=GROOVE).place(relx=0.9,rely=0.9)
# Marks window as used
hiddenwindow=1
pickle.dump(hiddenwindow, open("window.dat", "wb"))
self.top.mainloop()
def somewhereelse():
top.hide = True
top.hidden()
def quit_window(icon, item):
icon.stop()
root.destroy()
exit()
def show_window(icon, item):
icon.stop()
root.after(0,root.deiconify())
root.after(0,root.focus_force)
def hide_window():
root.withdraw()
image=Image.open("screen.ico")
try:
if pickle.load(open("window.dat","rb")) ==1:
menu=(item('Dev window', top.hidden),
item('show window', show_window),
item('Exit app', quit_window))
else:
menu=(item('Exit app', quit_window))
except:
menu=(item('Exit app', quit_window))
icon=pystray.Icon("ITextra", image, "Program", menu)
icon.run()
root = Tk()
root.title("ITextra")
root.geometry("400x400")
top = Top(root) #in main part
root.protocol('WM_DELETE_WINDOW', hide_window)
Button(root, text="Developer Options", padx=57, bg="#86b3b3",fg="black", command =top.hidden).grid(row=3,column=0)
root.mainloop()
Top window still unresponsive
It's not when root is open, but when top is open by itself, again it remains unresponsive. It responds however when I click a button, and drag my mouse. I tried adding a mainloop in top, but neither a self.top.mainloop nor a root.mainloop will work.
I tried using binds, but they also showed the same behaviour.
Am I creating something that won't work?
The app I'm creating is multithreaded, and my question is; would this complicate things with other classes? I am very new to coding, and quite frankly don't know.
I have the whole project in a pastebin here, for anyone who's interested. I think it's quite a mess, but I'm still pretty proud of it for a beginner.
The Toplevel() remains unresponsive because it has no event loop attached (mainloop()) because in this code the Toplevel acts as a standalone main window.
Need to attach this Toplevel to the root - top = Toplevel(root) where root is passed as argument to hidden(root). This way the root event loop works for all widget children such as a Toplevel. This would help towards your main part of the question.
(#added...) so there is no need for top.mainloop() because now that the root is the master/parent top is inside root.mainloop().
The event loop is for checking in to any events that happen on your widget which you would normally program with bind(). eg
top.bind('<Button>',dosomething) where dosomething is a defined function.
(...#added)
If you want a title for top then you need to create your own title baror label if you are using overrideredirect(True) because this removes the platform window manager.
(#added...)
The platform window manager is not so much removed as it is not being used when using overrideredirect(True). This is probably another reason why your window seems unresponsive with this stage of code. Need to code for events attached to the widget yourself - as you have done with the Button widget to close.
(...#added)
For main part of question:
there is nothing that refers to top widget in show_window in this code.
(#added...)
could look at making top a class and instantiate that in the root. The default status of hidden for top could be an attribute of this class. Then you can change the class attribute to hide or show functionally inside the body of the code somewhereelse.
eg skeleton sketch:
class Top():
def __init__(self,master=None):
...
self.hide = True
...
def hidden(self):
if self.hide:
...
def somewhereelse():
top.hide = true
top.hidden()
top = Top(root) #in main part
!!! obviously very brief general idea that needs work here of a way to maintain your design which seems quite good to me. There are several ways to incorporate the Toplevel widget into the class but that digresses a bit from the original question.
(...#added)
added 28Jan...
I recommend to study class more thoroughly rather than only putting in my example. But here is a bit more
class Top():
def __init__(self,master=None):
super().__init__()
self.master = master
self.hide = True
def hidden(self):
...
self.top = Toplevel(self.master)
...
In my words, but please check Python docs, super().__init__() will call the initialising function of the inherited object which in this case goes back to self.master which is root and then back through to tk.__init__ which is called in Tk().
I recommend looking at the code __init__.py file in the Lib\tkinter\ folder in the Python download to get a good understanding of how tkinter works.
I think this is definitely achievable but might need a different GUI - agree it is an excellent start for a beginner and thus not really a mess!!
Using class is not essential to achieving what you want to do but classes are very useful for encapsulating an object so that any extra attributes and methods relevant to that object can be customised for your project. This makes further or future development easier.
...added 28Jan
When I run this script, two windows appear, one for the file selection and the Tkinter window. How can I change this so that the Tkinter window only opens after a file has been selected? Thanks
def main():
my_file = askopenfilename()
stage1()
def stage1():
master = Tk()
master.mainloop()
The window master does open only after the file dialog closure (try to change its title to check), the first window you see is the parent window of the file dialog. Indeed, the tkinter file dialogs are toplevel windows, so they cannot exist without a parent window. So the first window you see is the parent window of the file dialog.
The parent window can however be hidden using the withdraw method and then restored with deiconify:
from tkinter import Tk
from tkinter.filedialog import askopenfilename
def main():
master = Tk()
master.withdraw() # hide window
my_file = askopenfilename(parent=master)
master.deiconify() # show window
master.mainloop()
if __name__ == '__main__':
main()
So for some reason the scale function in tkinter doesn't want to output the number on the scale. All i receive is either 0.0 or nothing. It seems to be to do with the GUI and calling functions through the GUI. Written and run in python 3.4.
from tkinter import *
from tkinter import ttk
from tkinter import messagebox
iterations=30
def settings():
global itervar, iterscale
sGui = Tk()
itervar = DoubleVar()
iterscale = Scale(sGui, orient="horizontal", from_=1, to=1000, variable=itervar)
iterscale.pack()
iterbutton = Button(sGui, text="Save Settings", command=saveSettings)
iterbutton.pack()
sGui.mainloop()
def saveSettings():
global iterations
iterations = itervar.get()
print(iterations)
def doNothing():
pass
def main():
global root, version
root= Tk()
menu = Menu(root)
root.config(menu=menu)
fileMenu = Menu(menu)
menu.add_cascade(label="File", menu=fileMenu)
fileMenu.add_command(label="Quit", command=quit)
benchmarkMenu = Menu(menu)
menu.add_cascade(label="Benchmark", menu=benchmarkMenu)
benchmarkMenu.add_command(label="Run [All]", command=doNothing)
benchmarkMenu.add_separator()
benchmarkMenu.add_command(label="Settings", command=settings)
root.mainloop()
#Main
main()
I have tried the functions settings and saveSettings on their own and they work fine, but when i call it through the GUI it doesn't seem to work.
Any ideas on the problem, my only solution would be have the settings function and saveSettings function in a different file and then run that file externally with os.startfile("etc...")
Minimal fix: change this
itervar = DoubleVar()
to this:
itervar = DoubleVar(sGui)
Because you have two root applications (root and sGui are both instances of Tk) the implied parent widget for itervar is the first one created, being root so tkinter gets confused when you specify it as the variable for a completely different application.
But I would highly recommend using a Toplevel instance to keep the windows a part of the same program:
sGui = Toplevel(root)
...
#sGui.mainloop() #no longer need this
although if you want to be able to run the setting window without the main one you might consider making all your visible windows Toplevels and make the actual root hidden:
# I'm not sure if you want to call it this
abs_root = Tk() # but you are already using root
abs_root.withdraw() #hide the window
Then make root = Toplevel(abs_root)
You coud phase out the variable all together by using .geting the scale directly:
iterations = iterscale.get()
I have a Python Program that opens a Toplevel window which is working I just wanted to know if there is an option to set the Toplevel window window to be active once it has been opened because at the moment it is still showing the parent window as the active window after opening it.
The python code (Python 3.4.1)
from tkinter import *
class cl_gui:
def __init__(self, master):
master.title("DataBox")
menu = Menu(master)
master.config(menu=menu)
menu_users = Menu(menu, tearoff=0)
menu.add_cascade(label="Users", menu=menu_users)
menu_users.add_command(label="View", command=self.f_openUsers)
def f_openUsers(self):
top = Toplevel()
top.title("Users")
root = Tk()
app = cl_gui(root)
root.mainloop()
You can set focus onto the new Toplevel widget as follows:
def f_openUsers(self):
top = Toplevel()
top.title("Users")
top.focus_set() # <- add this line
See e.g. this handy tkinter guide.