Develop Reference

.delete is not working inside class in tkinter

I am trying to make a tkinter desktop application (Notepad) using classes but I found an Attribute Error in my code. I made three files "menu_option.py", "textarea.py" and "window_frame.py". Run the "menu_option.py" file so that you found the error. I am using python (3.9). Also is there any another way to connect "new_file" function to menu item.
Here is my code below:
menu_option.py
from tkinter import *
from textarea import TextArea
from window_frame import Window
class Menu_Option(TextArea):
file = None
def __init__(self, master, newfile=None):
super().__init__(root)
self.Menubar = 'MenuBar'
self.Filemenu = 'FileMenu'
self.root = self.root
self.master = self.master
self.newfile = newfile
def launch(self):
self.Menubar = Menu(self.root)
self.Filemenu = Menu(master=self.Menubar, tearoff=0)
self.Filemenu.add_command(label='New File...', command=self.newfile)
self.Menubar.add_cascade(label='File', menu=self.Filemenu)
self.root.config(menu=self.Menubar)
class Features(Menu_Option):
def __init__(self, master):
super().__init__(master, newfile=self.new_file)
def new_file(self):
global file
self.root.title(self.title)
file = None
self.textarea.delete(1.0, END)
if __name__ == '__main__':
root = Tk()
Window(root).launch()
TextArea(root).launch()
Menu_Option(root).launch()
Features(root).launch()
root.mainloop()
textarea.py
from tkinter import *
from window_frame import Window
from tkinter.scrolledtext import ScrolledText
class TextArea(Window):
def __init__(self, name):
super().__init__(name)
self.name = self.root
self.master = 'root'
self.textarea = 'text_area'
self.font = 'courier 14 normal'
def launch(self):
self.textarea = ScrolledText(self.root, font=self.font)
self.textarea.pack(expand=True, fill=BOTH)
if __name__ == '__main__':
root = Tk()
Window(root).launch()
TextArea(root).launch()
root.mainloop()
window_frame.py
from tkinter import *
class Window:
def __init__(self, root):
self.root = root
self.geometry = '1000x550+100+100'
self.title = 'Untitled - ProBook'
def launch(self):
self.root.geometry(self.geometry)
self.root.title(self.title)
if __name__ == '__main__':
root = Tk()
Window(root).launch()
root.mainloop()
Error:
Exception in Tkinter callback
Traceback (most recent call last):
File "D:\Installed Programs\Python\lib\tkinter\__init__.py", line 1892, in __call__
return self.func(*args)
File "C:\Users\vaish\OneDrive\ProBook\menu_option.py", line 35, in new_file
self.textarea.delete(1.0, END)
AttributeError: 'str' object has no attribute 'delete'

Since Menu_Option() has override launch() function, therefore TextArea.launch() will not be executed and so instance variable textarea is still a string.
If child class wants to inherit parent class launch() functionality, you need to call the parent class launch() in its launch() function:
textarea.py
class TextArea(Window):
...
def launch(self):
super().launch() # call parent class launch()
self.textarea = ScrolledText(self.root, font=self.font)
self.textarea.pack(expand=True, fill=BOTH)
menu_option.py
class Menu_Option(TextArea):
...
def launch(self):
super().launch() # execute parent class launch()
...
...
if __name__ == "__main__":
root = Tk()
#Window(root).launch() # <- no need to execute
#TextArea(root).launch() # <- no need to execute
#Menu_Option(root).launch() # <- no need to execute
Features(root).launch()
root.mainloop()
Note that Window(root).launch(), TextArea(root).launch() and Menu_Option(root).launch() are not required.

You have initialized self.textarea="text_area" in textarea.py . But when you import it in menu_option.py, you are overwriting the function launch, which is supposed to set the value of self.textarea to a ScrolledText and pack it. To solve this you have to include the code in launch function of textarea.py in the function launch of Menu_Option class.
from tkinter import *
from tkinter.scrolledtext import ScrolledText
from textarea import TextArea
from window_frame import Window
class Menu_Option(TextArea):
file = None
def __init__(self, master, newfile=None):
super().__init__(root)
self.Menubar = 'MenuBar'
self.Filemenu = 'FileMenu'
self.root = self.root
self.master = self.master
self.newfile = newfile
def launch(self):
self.Menubar = Menu(self.root)
#You have to include these 2 lines of code which were overwritten
self.textarea = ScrolledText(self.root, font=self.font)
self.textarea.pack(expand=True, fill=BOTH)
self.Filemenu = Menu(master=self.Menubar, tearoff=0)
self.Filemenu.add_command(label='New File...', command=self.newfile)
self.Menubar.add_cascade(label='File', menu=self.Filemenu)
self.root.config(menu=self.Menubar)

Tkinter - The Root Window hides itself after close its Toplevel window

below my code:
from tkinter import *
from tkinter import ttk
class MainWindow:
def __init__(self):
self.parent=Tk()
self.parent.geometry("494x410+370+100")
self.parent.title("My Software - TEST")
self.parent.iconbitmap("icon.ico")
Button = ttk.Button(self.parent, text="open a new widnow", command=self.OpenNewWindow)
Button.place(x=16, y=16)
def OpenNewWindow(self):
self.obj = NewWindow(self)
class NewWindow:
def __init__(self, mw):
self.window, self.mw = Toplevel(mw.parent), mw
self.window.geometry("200x150+360+200")
self.window.title("New Window")
self.window.iconbitmap("icon.ico")
# the "try/except" code has an issue..
try:
self.window.focus()
self.mw.parent.attributes('-disabled', 1)
self.window.transient(mw.parent)
self.window.grab_set()
self.mw.parent.wait_window(self.window)
finally:
self.mw.parent.attributes('-disabled', 0)
def main():
app=MainWindow()
if __name__=="__main__":
main()
the try/except code makes the Toplevel window important. when it runs, the user can't touch the root window, and if he try to do it, a bell songs and the Toplevel window flashes. it's the exactly behaivour that I want! but this piece of code has an issue.. when the user close the Toplevel window, the root doesn't became the active window. it's a big issue because it makes the root window to go back the other ones. see my gif to understand better what I mean:
http://www.imagebam.com/image/c983ce1356199964
how can I solve this issue?

You've got the wrong idea about try ... finally; it does not work that way. There are 2 ways to do what you want. One way is to simply put that code in the main window:
from tkinter import *
from tkinter import ttk
class MainWindow:
def __init__(self):
self.parent=Tk()
self.parent.geometry("494x410+370+100")
self.parent.title("My Software - TEST")
self.parent.iconbitmap("icon.ico")
Button = ttk.Button(self.parent, text="open a new widnow", command=self.OpenNewWindow)
Button.place(x=16, y=16)
def OpenNewWindow(self):
self.parent.attributes('-disabled', 1)
self.obj = NewWindow(self)
self.parent.attributes('-disabled', 0)
class NewWindow:
def __init__(self, mw):
self.window, self.mw = Toplevel(mw.parent), mw
self.window.geometry("200x150+360+200")
self.window.title("New Window")
self.window.iconbitmap("icon.ico")
self.window.focus()
self.window.transient(mw.parent)
self.window.grab_set()
self.mw.parent.wait_window(self.window)
def main():
app=MainWindow()
app.parent.mainloop()
if __name__=="__main__":
main()
Another way is to make a method to run when the toplevel closes:
from tkinter import *
from tkinter import ttk
class MainWindow:
def __init__(self):
self.parent=Tk()
self.parent.geometry("494x410+370+100")
self.parent.title("My Software - TEST")
self.parent.iconbitmap("icon.ico")
Button = ttk.Button(self.parent, text="open a new widnow", command=self.OpenNewWindow)
Button.place(x=16, y=16)
def OpenNewWindow(self):
self.obj = NewWindow(self)
class NewWindow:
def __init__(self, mw):
self.window, self.mw = Toplevel(mw.parent), mw
self.window.geometry("200x150+360+200")
self.window.title("New Window")
self.window.iconbitmap("icon.ico")
self.window.protocol("WM_DELETE_WINDOW", self.on_close)
self.window.focus()
self.mw.parent.attributes('-disabled', 1)
self.window.transient(mw.parent)
self.window.grab_set()
self.mw.parent.wait_window(self.window)
def on_close(self):
self.mw.parent.attributes('-disabled', 0)
self.window.destroy()
def main():
app=MainWindow()
app.parent.mainloop()
if __name__=="__main__":
main()

Tkinter passing callback function result to another class

I wonder how to pass return value from one class to another class in tkinter.
In my program I have DataChosenForm class where I want to choose option in Combobox and pass this result to another class ReturnData to set a variable in a Label.
import tkinter as tk
from tkinter import ttk
class DataChosenForm(tk.Frame):
def __init__(self, parent):
super().__init__(parent)
chosen = tk.LabelFrame(self, text="wybór")
chosen.grid(row=0)
self.combo = ttk.Combobox(chosen)
self.combo['values'] = ('wizz', 'ryanair', 'lot')
self.combo.grid(row=0, column=2, padx=80, pady=10)
self.combo.bind("<<ComboboxSelected>>", self.callback)
def callback(self, event=None):
if event.widget.get() == 'wizz':
print('wizz')
return 'wizz'
elif event.widget.get() == 'ryanair':
print('ryanair')
return 'ryanair'
elif event.widget.get() == 'lot':
print('lot')
return 'lot'
class ReturnData(tk.Frame):
def __init__(self, parent):
super().__init__(parent)
var = tk.StringVar()
message_box = tk.LabelFrame(self, text="wynik")
message_box.grid(row=1)
mb = tk.Label(message_box, textvariable=var,anchor='nw')
mb.pack(padx=120, pady=30)
class Application(tk.Tk):
def __init__(self):
super().__init__()
self.title("program do wyszukiwania cen lotów")
self.geometry('300x200')
self.resizable(width=False, height=False)
DataChosenForm(self).grid(row=0, column=0)
ReturnData(self).grid(row=1)
if __name__ == "__main__":
app = Application()
app.mainloop()

You could first display the combobox DataChosenForm(self).grid(row=0, column=0) without calling the ReturnData in the Application class.
Then, in the callback() method collect the choice choice = event.widget.get() and pass it to ReturnData. This would mean, however, that the LabelFrame is displayed only after a choice is made.
import tkinter as tk
from tkinter import ttk
class DataChosenForm(tk.Frame):
def __init__(self, parent):
super().__init__(parent)
chosen = tk.LabelFrame(self, text="wybór")
chosen.grid(row=0)
self.combo = ttk.Combobox(chosen)
self.combo['values'] = ('wizz', 'ryanair', 'lot')
self.combo.grid(row=0, column=2, padx=80, pady=10)
self.combo.bind("<<ComboboxSelected>>", self.callback)
def callback(self, event=None):
choice = event.widget.get()
print(choice)
ReturnData(self, choice).grid(row=1)
class ReturnData(tk.Frame):
def __init__(self, parent, choice):
super().__init__(parent)
message_box = tk.LabelFrame(self, text="wynik")
message_box.grid(row=1)
mb = tk.Label(message_box, text=choice, anchor='nw')
mb.pack(padx=120, pady=30)
class Application(tk.Tk):
def __init__(self):
super().__init__()
self.title("program do wyszukiwania cen lotów")
self.geometry('300x200')
self.resizable(width=False, height=False)
DataChosenForm(self).grid(row=0, column=0)
if __name__ == "__main__":
app = Application()
app.mainloop()

I think #Julia has the basically the right architecture for your tkinter application, but her answer could be improved by using a tkinter Variable — because all widgets associated with one will automatically update their displayed value whenever the Variable is changed (by one of them or something else).
Here's a little documentation on Variable Classes. Note that since ttk.Combobox with have all the methods of a tk.Entry widgets, here's a bit of documentation about them (which also happens to illustrate the "pattern" of using of a StringVar in conjunction with one so it also applies to a ttk.Comboboxs).
Generally, you can tell a widget to use a tkinter Variable by specifying an instance of one as the option textvariable= keyword argument when the widget is created. You can also set the option using the partial dictionary interface most widgets support, so assignments like widget['textvariable'] = variable are another way to make use of them — the code below makes use of both of these ways.
Here's Julia's code modified to use a tk.StringVar. Note the Combobox doesn't need a callback function to bind the <<ComboboxSelected>> event to it, so all that complexity has been eliminated.
import tkinter as tk
from tkinter import ttk
class DataChosenForm(tk.Frame):
def __init__(self, parent):
super().__init__(parent)
choice = tk.LabelFrame(self, text="wybór")
choice.grid(row=0)
self.combo = ttk.Combobox(choice)
self.combo['textvariable'] = parent.var # Use shared variable.
self.combo['values'] = ('wizzair', 'ryanair', 'lot')
self.combo.grid(row=0, column=2, padx=80, pady=10)
class ReturnData(tk.Frame):
def __init__(self, parent):
super().__init__(parent)
message_box = tk.LabelFrame(self, text="wynik")
message_box.grid(row=1)
mb = tk.Label(message_box, textvariable=parent.var, # Use shared variable.
anchor='nw', width=20)
mb.pack(padx=120, pady=30)
class Application(tk.Tk):
def __init__(self):
super().__init__()
self.title("program do wyszukiwania cen lotów")
self.geometry('300x200')
self.resizable(width=False, height=False)
self.var = tk.StringVar(value='Dokonać wyboru') # Create shared variable.
DataChosenForm(self).grid(row=0, column=0)
ReturnData(self).grid(row=1)
if __name__ == "__main__":
app = Application()
app.mainloop()

You can just pass other class or it's field to __init__ of the DataChosenForm, and to callback function from there, where then you can change class/field directly. Here's what I mean, but I use TreeView:
import tkinter as tk
from tkinter import ttk
class ConnectedClass:
def __init__(self):
self.received = "will be changed"
class TreeViewWrapper(ttk.Treeview):
def __init__(self, master, connected_class, **kw):
super().__init__(master, **kw)
parents = []
for i in range(10):
parent = self.insert("", "end", text="Item %s" % i, tags=str(i))
for i in range(3):
self.insert(parent, "end", text="Item %s" % i, tags=str(i))
self.bind("<Control-r>", lambda e: self.pass_to_other(e, connected_class))
def pass_to_other(self, _, connected_class):
items = self.selection()
connected_class.received = items
class App:
def __init__(self):
self.root = tk.Tk()
self.con_class = ConnectedClass()
self.tree = TreeViewWrapper(self.root,self.con_class)
self.tree.pack()
self.root.bind("<Control-p>",lambda e:print(self.con_class.received))
self.root.mainloop()
if __name__ == "__main__":
app = App()

Tkinter in python3, menubar does not working

Well, i want to add menubar, but something is going wrong.
It says: AttributeError: 'NoneType' object has no attribute 'config'
My code:
from tkinter import *
class ApplicationWindow(Tk):
def __init__(self, master=None):
Tk.__init__(self, master)
self.master = master
self.geometry('800x400')
self.f_app = Frame(self).pack()
menubar = Menu(self.master)
self.master.config(menu=menubar)
fileMenu = Menu(menubar)
fileMenu.add_command(label="Exit", command=self.onExit)
menubar.add_cascade(label="File", menu=fileMenu)
self.b_log = Button(self, width=10, text="Войти", command=self.func).pack()
def onExit(self):
self.quit()
def func(self):
print("hello")
def main():
# root = tk
app = ApplicationWindow()
app.mainloop()
if __name__ == '__main__':
main()

You're initializing your ApplicationWindow class without passing any arguments in, like this app = ApplicationWindow(). In your init method, you give master a None default, and when you try to use master.config it says
'NoneType' object has no attribute 'config'
Try passing an argument in when you initialize the instance of ApplicationWindow. Whatever it is that you want master to be (just not a None object).
I have updated your code (below) and it runs. The button works, and the exit function closes the window. There was a lot to fix, but it runs without error. Take it from here:
import tkinter
class ApplicationWindow(tkinter.Tk):
def __init__(self, master=None):
# Tk.__init__(self, master)
self.master = master
self.master.geometry('800x400')
self.master.f_app = tkinter.Frame(self.master).pack()
menubar = tkinter.Menu(self.master)
self.master.config(menu=menubar)
fileMenu = tkinter.Menu(menubar)
fileMenu.add_command(label="Exit", command=self.onExit)
menubar.add_cascade(label="File", menu=fileMenu)
self.b_log = tkinter.Button(self.master, width=10, text="Войти", command=self.func).pack()
def onExit(self):
self.master.destroy()
def func(self):
print("hello")
def main():
root = tkinter.Tk()
app = ApplicationWindow(root)
root.mainloop()
if __name__ == '__main__':
main()

You have an argument named master=None defaults to None. So when you create an instance of ApplicationWindow() without parameter your master argument gets None, and here you are calling config() method but your master is none and it doesnt have a method named config.
class ApplicationWindow(Tk):
def __init__(self, master=None):
...
self.master.config(menu=menubar) # Error accurred here
def main():
# root = tk
app = ApplicationWindow() # pass an argument

tkinter quit crash

I am very new to Tkinter. I made this "Hello World"-like GUI program in Tkinter. However, every time I click on the quit button, the program crashes. Thanks in advance!
from Tkinter import *
import sys
class Application(Frame):
def __init__(self,master=None):
Frame.__init__(self,master=None)
self.grid()
self.createWidgets()
def createWidgets(self):
self.quitButton = Button(text='Quit',command=self.quit)#Problem here
self.quitButton.grid()
app = Application()
app.master.title("Sample application")
app.mainloop()

In Tkinter the root element is a Tk object. Application should be a subclass of Tk, not Frame:
from Tkinter import *
import sys
class Application(Tk):
def __init__(self):
Tk.__init__(self)
self.grid()
self.createWidgets()
def createWidgets(self):
self.quitButton = Button(text='Quit',command=self.destroy) # Use destroy instead of quit
self.quitButton.grid()
app = Application()
app.title("Sample application")
app.mainloop()

This Code works fine now:
import tkinter
class MyApp(tkinter.LabelFrame):
def __init__(self, master=None):
super().__init__(master, text="Hallo")
self.pack(expand=1, fill="both")
self.createWidgets()
self.createBindings()
def createWidgets(self):
self.label = tkinter.Label(self)
self.label.pack()
self.label["text"] = "Bitte sende ein Event"
self.entry = tkinter.Entry(self)
self.entry.pack()
self.ok = tkinter.Button(self)
self.ok.pack()
self.ok["text"] = "Beenden"
self.ok["command"] = self.master.destroy
def createBindings(self):
self.entry.bind("Entenhausen", self.eventEntenhausen)
self.entry.bind("<ButtonPress-1>", self.eventMouseClick)
self.entry.bind("<MouseWheel>", self.eventMouseWheel)
def eventEntenhausen(self, event):
self.label["text"] = "Sie kennen das geheime Passwort!"
def eventMouseClick(self, event):
self.label["text"] = "Mausklick an Position " \
"({},{})".format(event.x, event.y)
def eventMouseWheel(self, event):
if event.delta < 0:
self.label["text"] = "Bitte bewegen Sie das Mausrad"\
" in die richtige Richtung."
else:
self.label["text"] = "Vielen Dank!"
root = tkinter.Tk()
app = MyApp(root)
app.mainloop()

When you use self.quit() the python interpreter closes down without the tkinter application bieng closed . So try .destroy() command and after .mainloop() use sys.quit(). Hope this helps.

Your using __init__ difficultly. Do this:
from tkinter import *
root = Tk()
btn_quit = Button(root, text='Quit', command=quit()).pack()
root.mainloop()
If you do self.quit, that is the quit command so the thing will crash!
Hope this helps!

try using raise SystemExit
this may be better.
or check out me