Major error in ttkboostrap

Desktop (please complete the following information):

Hi,

I use the following code to spawn the next UI, but iam getting error _tkinter.TclError: NULL main window

from tkinter import *
from ttkbootstrap import Style
from tkinter import ttk
import multiprocessing


class GuiApp(object):
    def __init__(self):
        self.style = Style(theme='litera')
        self.style.configure('lefttab.TNotebook', tabposition='wn')
        self.style.configure('TNotebook.Tab', align=LEFT)
        self.root = self.style.master
        tabone = ttk.Button(self.root, text="Campaigns")
        tabone.place(x=20, y=20)
        tabtwo = ttk.Button(self.root, text="Settings")
        tabtwo.place(x=27, y=60)
        self.root.geometry("850x550")
        self.root.resizable(False, False)
def validate():
    second.destroy()
    multiprocessing.freeze_support()
    gui = GuiApp()
    gui.root.mainloop()
def validate_lic():
   global second
   global emailentry
   global passentry
   global keyentry
   global validate_btn
   style = Style(theme='litera')
   second = style.master
   validate_btn = ttk.Button(second, text="Sign-in", command=validate)
   validate_btn.place(x=155, y=150)
   second.geometry("350x300")
   second.resizable(False, False)
   # second.iconbitmap("Icon.ico")
   second.mainloop()


if __name__ == '__main__':
    multiprocessing.freeze_support()
    validate_lic()

If i tried with same code with ttkboostrap version 0.5.1 then no issue.

Describe the bug

Getting _tkinter.TclError: NULL main window bug when it was trying to spawn other UI

To Reproduce

Just run the code and click on sign in button, you can see the bug

Expected behavior

It has to spawn the other UI, it works fine V0.5.1, but not in the current.

Screenshots

https://i.imgur.com/8zaETCY.png

Additional context

No response

[sunny9495-dev]

Ok, Thanks @israel-dryer

Thank you for your excellent support

[israel-dryer]

I need to look into this further, but generally, it is not a recommended practice to use more than one tcl/tk interpreter in your application. This is what Toplevel widgets are created for. There are several ways to accomplish what you want without closing and reopening a new application window.

On solution, as I mentioned, is to use Toplevel widgets. Another solution (demonstrated below) is to use frames to control and contain your content.

import ttkbootstrap as ttk
from ttkbootstrap.constants import *

THEME = 'litera'
APP_SIZE = (850, 550)

class GuiApp(ttk.Window):

    def __init__(self):
        super().__init__(themename=THEME, size=APP_SIZE, resizable=(False, False))
        self.is_valid_license = ttk.BooleanVar(self, name='is_valid_license', value=False)
        self.is_valid_license.trace_add('write', self.on_license_validation)
        # setup frames
        self.setup_custom_styles()
        self.validation_frame = LicenseValidationFrame(self)
        self.main_frame = MainAppFrame(self)
        # show the initial validation frame
        self.show_validation_frame()

    def show_main_frame(self):
        self.main_frame.pack(fill=BOTH, expand=YES)

    def show_validation_frame(self):
        if not self.validation_frame.winfo_ismapped():
            self.validation_frame.pack(fill=BOTH, expand=YES)

    def setup_custom_styles(self):
        self.style.configure('lefttab.TNotebook', tabposition='wn')
        self.style.configure('TNotebook.Tab', align=LEFT, fill=X)
        self.style.layout('TNotebook.Tab', [])

    def on_license_validation(self, *args):
        if self.is_valid_license.get():
            self.validation_frame.pack_forget()
            self.show_main_frame()

class MainAppFrame(ttk.Frame):

    def __init__(self, master, **kwargs):
        super().__init__(master, **kwargs)

        # setup buttons
        self.lframe = ttk.Frame(self, padding=(10, 10, 0, 10))
        self.lframe.pack(side=LEFT, fill=Y)
        self.tab1_btn = ttk.Button(self.lframe, text='Campaigns')
        self.tab2_btn = ttk.Button(self.lframe, text='Settings')
        self.tab3_btn = ttk.Button(self.lframe, text='Reports')
        self.tab1_btn.pack(side=TOP, fill=X)
        self.tab2_btn.pack(side=TOP, fill=X)
        self.tab3_btn.pack(side=TOP, fill=X)

        # setup notebook & tabs
        self.rframe = ttk.Frame(self)
        self.rframe.pack(side=RIGHT, fill=BOTH)
        self.notebook = ttk.Notebook(self.rframe, style='lefttab.TNotebook')
        self.notebook.pack(fill=BOTH, expand=YES, padx=10, pady=10)

        tab_cnf = {'width': 700, 'height': 500}
        # tab 1 setup
        self.tab1 = CampaignTab(self.notebook)
        self.tab2 = ttk.Frame(self.notebook, **tab_cnf)
        self.tab3 = ttk.Frame(self.notebook, **tab_cnf)
        self.tab4 = ttk.Frame(self.notebook, **tab_cnf)
        self.tab5 = ttk.Frame(self.notebook, **tab_cnf)
        self.tab6 = ttk.Frame(self.notebook, **tab_cnf)
        self.notebook.add(self.tab1, text='Campaigns')
        self.notebook.add(self.tab2, text='Settings')
        self.notebook.add(self.tab3, text='Reports')
        self.notebook.add(self.tab4, text='Add New Campaign')
        self.notebook.add(self.tab5, text='Camp Reports')
        self.notebook.add(self.tab6, text='Log Reports')


class CampaignTab(ttk.Frame):
    def __init__(self, master, **kwargs):
        super().__init__(master, width=700, height=500, **kwargs)
        # create tab elements
        self.camp_lbl = ttk.Label(self, text='Campaigns', bootstyle=INFO, font='Helvetica 14 bold')
        self.add_camp = ttk.Button(self, text='Add New Campaign', bootstyle=PRIMARY)
        self.search_lbl = ttk.Label(self, text='Search', bootstyle=INFO, font='Arial 11')
        self.search_entry = ttk.Entry(self)
        # set layout
        self.camp_lbl.pack(pady=10)
        self.add_camp.pack(pady=10)
        self.search_entry.pack(pady=10)


class LicenseValidationFrame(ttk.Frame):

    def __init__(self, master, **kwargs):
        super().__init__(master, **kwargs)
        btn = ttk.Button(self, text='Sign-in', command=self.validate)
        btn.place(anchor=CENTER, relx=0.5, rely=0.5)

    def validate(self):
        """perform some function to validate the license then update
        the is_valid_license variable"""
        is_valid_license = ttk.BooleanVar(name='is_valid_license')
        is_valid_license.set(True)


if __name__ == '__main__':
    app = GuiApp()
    app.mainloop()

In fact, since you are creating your own notebook buttons, you really do not need to use the notebook widget at all, just use the pack_forget method to remove the frame from the window as I did for the license frame above, and then pack the tab you want to show. The result will be the same except you won’t need to do a lot of customizations on the notebook widget.

One other tip, I would avoid using place with x & y coordinates. If someone has a high resolution screen, the placement of widgets will be very different than you expect. If you need to use the place geometry manager, prefer to use relx or rely to make relative position placements.

here’s with just the tabs