Getting variable from class that uses input

Question

I am making a window in tkinter that requires additional input for a name. To get this input I created a special messagebox that gets the input and has a button to confirm the input in the entry. I need to then get that variable from the class as the return value. The problem is that I do not know how to get such a value when the user could take however long they wish. What should I do? (The value I need to return is extension_name)

My current code:

class ExtensionNamer(Toplevel):
    def __init__(self, master, x, y, *args, **kwargs):
        #Initialize the window
        Toplevel.__init__(self, master, *args, **kwargs)
        #Set basic window properties
        self.title("Extension Naming")
        self.geometry("300x100+{}+{}".format(x, y))
        self.attributes("-topmost", True)
        self.resizable(False, False)
        self.grab_set()
        #Create the widgets
        self.extension_name_label = Label(self, text="Extension Name:", font=medium_font)
        self.extension_name_label.place(relx=0.5, rely=.15, anchor=CENTER)
        self.extension_name_entry = Entry(self, font=normal_font, width=20, justify=CENTER)
        self.extension_name_entry.place(relx=0.5, rely=.5, anchor=CENTER)
        self.confirm_button = Button(self, text="Confirm", font=normal_font, command=self.confirm)
        self.confirm_button.pack(anchor=S, side=LEFT)
        self.cancel_button = Button(self, text="Cancel", font=normal_font, command=self.cancel)
        self.cancel_button.pack(anchor=S, side=RIGHT)
        self.protocol("WM_DELETE_WINDOW", self.cancel)

    def confirm(self):
        #Confirm the extension name
        self.extension_name = self.extension_name_entry.get()
        if ".xt" not in self.extension_name:
            self.extension_name += ".xt"
        self.destroy()

    def cancel(self):
        #Cancel the extension name
        self.extension_name = "NewXT.xt"
        self.destroy()
...
    def add_tab(self, event=None):
        #Adds a new tab
        tab_name = ExtensionNamer(self, self.winfo_x(), self.winfo_y(), color_mode=self.color_mode)

The ExtensionNamer class should take a callback parameter. The confirm() method can call this when it confirms the entry. — Barmar
– Barmar, Commented Jun 15, 2022 at 21:59

Barmar · Accepted Answer · 2022-06-15 22:35:15Z

1

Add a callback function parameter to the class. When the user confirms the extension, this function will be called with the extension name.

This is similar to the way Tkinter widgets take a command parameter, and you use it the same way. When calling ExtensionNamer(), add a callback= argument that specifies the function that will use the extension name after the user has confirmed it.

class ExtensionNamer(Toplevel):
    def __init__(self, master, x, y, callback, *args, **kwargs):
        #Initialize the window
        super().__init__(self, master, *args, **kwargs)
        self.callback = callback
        #Set basic window properties
        self.title("Extension Naming")
        self.geometry("300x100+{}+{}".format(x, y))
        self.attributes("-topmost", True)
        self.resizable(False, False)
        self.grab_set()
        #Create the widgets
        self.extension_name_label = Label(self, text="Extension Name:", font=medium_font)
        self.extension_name_label.place(relx=0.5, rely=.15, anchor=CENTER)
        self.extension_name_entry = Entry(self, font=normal_font, width=20, justify=CENTER)
        self.extension_name_entry.place(relx=0.5, rely=.5, anchor=CENTER)
        self.confirm_button = Button(self, text="Confirm", font=normal_font, command=self.confirm)
        self.confirm_button.pack(anchor=S, side=LEFT)
        self.cancel_button = Button(self, text="Cancel", font=normal_font, command=self.cancel)
        self.cancel_button.pack(anchor=S, side=RIGHT)
        self.protocol("WM_DELETE_WINDOW", self.cancel)

    def confirm(self):
        #Confirm the extension name
        self.extension_name = self.extension_name_entry.get()
        if ".xt" not in self.extension_name:
            self.extension_name += ".xt"
        self.destroy()
        self.callback(self.extension_name)

You would use it something like this:

    def add_tab(self, event=None):
        #Adds a new tab
        tab_name = ExtensionNamer(self, self.winfo_x(), self.winfo_y(), callback=self.display_name, color_mode=self.color_mode)

    def display_name(self, name):
        print(f'Extension name is {name}')

edited Jun 15, 2022 at 22:35

answered Jun 15, 2022 at 22:17

Barmar

789k57 gold badges555 silver badges669 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

TRCK Over a year ago

When I call the class how do I enable the callback? This currently gives the error TypeError: ExtensionNamer.__init__() missing 1 required positional argument: 'callback'

Barmar Over a year ago

You pass the function that wants to use the name as another argument. I explained that in the answer, it's similar to the way you use command=confirm when creating the button widget.

Barmar Over a year ago

ExtensionNamer(master, x, y, callback=function_that_uses_extension_name)

TRCK Over a year ago

So callback=confirm?

Barmar Over a year ago

No. confirm() is the function that calls the callback.

|

Collectives™ on Stack Overflow

Getting variable from class that uses input

1 Answer 1

9 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

9 Comments

Your Answer

Sign up or log in

Post as a guest

Related