[Tutor] destroying windows

[Cédric Lucantis]

Le Monday 30 June 2008 14:47:39 Jim Morcombe, vous avez écrit :
> I want to have a program that uses Tkinter to display a window.
> If the user selects an option, then I want to destroy that window and
> then display a second window.
> In turn, the user can select an option to change back to the first
> window and I want to destroy that window and then display the first again.
>
> I have pasted my code below.  The window is successfully created.
> However, I can't figure out the correct way to destroy it.
> In my first attempt, "window1" is not defined when I go to destroy it
> and I am not sure how to make "window1" global or what.
>

Using global variables may help for simple scripts, but is not a good practice 
in general. Anyway you could it like this:

# this in the global scope
window1 = None

class display_Colour_Selector_window():
	def __init__(self):
		global window1
		window1 = Tk()
		...

def change_to_Colour_Picker():
	window1.destroy

(note that the global statement is only required when you set the variable, 
not when you only read it)

But a better design would be to use instance attributes and methods for your 
callbacks instead, so the whole stuff is 'packed' inside your class:

class display_Colour_Selector_window():

    def __init__(self):
        self.window1 = Tk()
        self.window1.title("Colour Selector")

        menubar = Menu(self.window1)

        # create pulldown menus
        editmenu = Menu(menubar, tearoff=0)
        editmenu.add_command(label="Colour Picker", 
command=self.change_to_Colour_Picker)
        menubar.add_cascade(label="Edit", menu=editmenu)

        # display the menu
        self.window1.config(menu=menubar)

    def change_to_Colour_Picker (self) :
        self.window1.destroy()
        display_Colour_Picker_window()

-- 
Cédric Lucantis