[Tkinter] Spawn sub-window with button press

[malonn]

Hey, I'm trying to open a sub-window on top of my main window for a specific time, then close it. I'm going the tkinter.Toplevel route for this and plan on destroying it with subwindow.destroy(). But I keep getting an error that I have no idea what to do with. Code:

class MainWindow(ttk.Frame):
    def __init__(self, parent):
        ttk.Frame.__init__(self)
        ttk.Frame.grid(self, column=0, row=0, sticky=('N', 'E', 'S', 'W'))
        ttk.Frame.columnconfigure(self, 0, weight=1)
        ttk.Frame.rowconfigure(self, 0, weight=1)
        self.mem_exists = tkinter.StringVar()
        self.reg_scan = tkinter.StringVar()
        self.widgets()

    def widgets(self):
        self.mem_labl1 = ttk.Label(self, text='Memory Dumps:')
        self.mem_labl1.grid(column=0, row=0)
        self.mem_labl2 = ttk.Label(self, textvariable=self.mem_exists)
        self.mem_labl2.grid(column=0, row=1)
        self.mem_buton = ttk.Button(self, text='Delete', command=self.delete_dmps)
        self.mem_buton.grid(column=0, row=2)
        self.dmp_separ = ttk.Separator(self, orient='horizontal')
        self.dmp_separ.grid(column=0, row=3, rowspan=1, sticky=('EW'))
        self.scn_labl1 = ttk.Label(self, text='Scan for Dumps')
        self.scn_labl1.grid(column=0, row=4)
        self.scn_buton = ttk.Button(self, text='Scan', command=self.scan_pressed)
        self.scn_buton.grid(column=0, row=5)
        self.vrt_separ = ttk.Separator(self, orient='vertical')
        self.vrt_separ.grid(column=1, row=0, rowspan=6, sticky=('NS'))
        self.reg_labl1 = ttk.Label(self, text='Unneeded Keys')
        self.reg_labl1.grid(column=2, row=0)
        self.reg_labl2 = ttk.Label(self, textvariable=self.reg_scan)
        self.reg_labl2.grid(column=2, row=1)
        self.reg_buton = ttk.Button(self, text='Delete', command=self.delete_keys)
        self.reg_buton.grid(column=2, row=2)
        ......
    def scan_pressed(self):
        self.sub_win = tkinter.Toplevel(self, root) <----- ERROR HERE
        self.write_dumps()
        size = self.get_size()
        self.mem_exists.set(f'{size} KB of memory dumps found!')

When I press the button (scn_buton) I want it to spawn a little window with a label that says "scanning..." (or something of that nature), but it gives me this error:

Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Python37\lib\tkinter\__init__.py", line 1705, in __call__
return self.func(*args)
File "c:\users\mark\downloads\practice_gui_2.py", line 83, in scan_pressed
self.sub_win = tkinter.Toplevel(self, root)
File "C:\Python37\lib\tkinter\__init__.py", line 2334, in __init__
if wmkey in cnf:
File "C:\Python37\lib\tkinter\__init__.py", line 1489, in cget
return self.tk.call(self._w, 'cget', '-' + key)
TypeError: can only concatenate str (not "int") to str

I have no clue where to even begin on that one. Google results turn up things not related to tkinter.

malonn

---

Well, I figured out why the window wouldn't spawn. The fix was to remove the master from the call to Toplevel() like so

self.sub_win = tkinter.Toplevel(self)

but the window doesn't spawn until after the rest of the code for that method ("scan_pressed") is run. Why is that? The code calls os.walk which takes a while to complete and I want the second window to block it while it happens.