how to remove a circular dependency in tkinter gui - python-3.x

Question

I'm in the very early stages of making a GUI. Right now I have the log in view(LogInWind class) and the sign up view (SignUpWind class). Everything was fine when I only had one view but now I have a circular dependency with these two objects. This happens with the buttons' command since in the log in view there is a button that takes you to the sign up view and vise versa. I think I could just make a pop up window for the sign up view. Yet I think the way I'm switching windows is a bad practice an may bring bigger issues later on.
I'm project structure is the following.
the services package will do the connection between the gui and the database. At the moment it does nothing.
I'm happy to get feedback for everything. If further explanation is needed I'm happy to do so.
root.py
import tkinter as tk
from .log_in_window import LogInWind as LIWind
from .sign_up_window import SignUpWind as SuWind
from services.messenger import Messenger
class Root(tk.Tk):
def __init__(self, *args,**kwargs):
super().__init__(*args,**kwargs)
# General variables.
self.frames = {}
self.width_window
self.height_window
self.container = tk.Frame(self,relief="groove")
# General app configurations.
self.title("SECOM")
self.iconbitmap("C:/Users/joshu/Documents/VSC/python/secom/icons/icon.ico")
self.configure(bg="#E0E0E0")
# Container setup.
self.container.pack(side="top", fill="both", expand=True)
self.container.grid_rowconfigure(0, weight=1)
self.container.grid_columnconfigure(0, weight=1)
def createFrame(self, page_name):
"""
INPUT: view object.
OUTPUT: None
Description: creates frame for the view `page_name`.
"""
# Setup `newFrame.`
newFrame = page_name(parent=self.container, controller=self)
newFrame.configure(bg="#E0E0E0")
newFrame.grid(row=0, column=0, sticky=tk.NSEW)
# Add `newFrame` to catalog of frames.
self.__frames[page_name] = newFrame
def showFrame(self, page_name):
"""
INPUT: view object.
OUTPUT: None.
Calls the view `page_name` up front for display.
"""
try:
# Bings requested view to the front.
self.frames[page_name].tkraise()
except KeyError:
# Creates view and displays it.
self.createFrame(page_name)
self.frames[page_name].tkraise()
def setLocation(self):
"""
INPUT: None
OUTPUT: None
Description: Sets window in the middle of the screen.
"""
self.widthWindow = 400
self.heightWindow = 225
widthScreen = self.winfo_screenwidth()
hightScreen = self.winfo_screenheight()
x = (widthScreen / 2) - (self.widthWindow / 2)
y = (hightScreen / 2) - (self.heightWindow / 2)
self.geometry("%dx%d+%d+%d" % (self.widthWindow, self.heightWindow, x, y))
log_in_window.py
import tkinter as tk
import tkinter.font as tkf
from .sign_up_window import SignUpWind as SUWind # <-- circular dependency
class LogInWind(tk.Frame):
def __init__(self, parent, controller):
super().__init__(parent, controller)
# Creation of labels.
self.titleLbl = tk.Label(self,
text="Iniciar Secion",
font=tkf.Font(family="Helvetica", size=15, weight="bold"),
bg="#E0E0E0")
self.userLbl = tk.Label(self,
text="Usuario:",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#E0E0E0")
self.pswdLbl = tk.Label(self,
text="Contraseña:",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#E0E0E0")
# Creation of entries.
self.userEty = tk.Entry(self)
self.pswdEty = tk.Entry(self, show="*")
# Creation of buttons.
self.logInBtn = tk.Button(self,
width=15,
text="Iniciar Sesion",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#0080FF",
################################### ADD COMMAND
fg="#fff")
self.signUpBtn = tk.Button(self,
width=15,
text="Crear cuenta",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#0080FF",
command=lambda: controller.showFrame(SUWind), # <---- use object HERE.
fg="#fff")
# Places labels.
self.titleLbl.grid(row=0,
column=0,
padx=400 / 2 - 60,
pady=10,sticky=tk.SW)
self.userLbl.grid(row=1,
column=0,
padx=parent.width_window / 2 - 60,
sticky=tk.SW)
self.pswdLbl.grid(row=3,
column=0,
padx=parent.width_window / 2 - 60,
sticky=tk.W)
# Places entries (string inputs).
self.userEty.grid(row=2,
column=0,
padx=parent.width_window / 2 - 60,
pady=5)
self.pswdEty.grid(row=4,
column=0,
padx=parent.width_window / 2 - 60,
pady=5)
# # Places buttons
self.logInBtn.grid(row=5,column=0, sticky=tk.N)
self.signUpBtn.grid(row=6, column=0, sticky=tk.S, pady=10)
sing_up_window.py
import tkinter as tk
import tkinter.font as tkf
from .log_in_window import LogInWind as LIWind # <-- circular dependency
class SignUpWind(tk.Frame):
def __init__(self, parent, controller):
super().__init__(parent, controller)
# Setup imge for back button.
self.img = tk.PhotoImage(file="C:/Users/joshu/Documents/VSC/python/secom/icons/return.png")
self.img = self.img.subsample(4,4)
# Create label.
self.titleLbl = tk.Label(self,
text="Crear cuenta nueva",
font=tkf.Font(family="Helvetica", size=15, weight="bold"),
bg="#E0E0E0")
self.userLbl = tk.Label(self,
text="Usuario:",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#E0E0E0")
self.pswdLbl = tk.Label(self,
text="Contraseña:",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#E0E0E0")
self.pswdConfirmLbl = tk.Label(self,
text="Cormirma Contraseña:",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#E0E0E0")
# Creation of entries.
self.userEty = tk.Entry(self)
self.pswdEty = tk.Entry(self, show="*")
self.pswdConfirmEty = tk.Entry(self, show="*")
# Creation of button.
self.backBtn = tk.Button(self,
image=self.img,
command=lambda: controller.showFrame(LIWind)) <----- use object HERE.
self.CreateBtn = tk.Button(self,
width=8,
text="Crear",
font=tkf.Font(family="Helvetica", size=10, weight="bold"),
bg="#0080FF",
############################ ADD COMAND
fg="#fff")
# Places labels.
self.titleLbl.grid(row=0, column=0, padx=400 / 2 - 90, sticky=tk.SW)
self.userLbl.grid(row=1, column=0, padx=parent.width_window / 2 - 60, sticky=tk.W)
self.pswdLbl.grid(row=3, column=0, padx=parent.width_window / 2 - 60, sticky=tk.W)
self.pswdConfirmLbl.grid(row=5, column=0, padx=parent.width_window / 2 - 60, sticky=tk.W)
# Places entries (string inputs).
self.userEty.grid(row=2, column=0, padx=parent.width_window / 2 - 60, pady=5, sticky=tk.W)
self.pswdEty.grid(row=4, column=0, padx=parent.width_window / 2 - 60, pady=5, sticky=tk.W)
self.pswdConfirmEty.grid(row=6, column=0, padx=parent.width_window / 2 - 60, pady=5, sticky=tk.W)
# Places buttons
self.backBtn.grid(row=0, column=0,sticky=tk.W)
self.CreateBtn.grid(row=7, column=0, padx=100,sticky=tk.N)
main.py
from views.root import Root
from views.log_in_window import LogInWind as LIWind
if __name__ == '__main__':
root = Root()
root.showFrame(LIWind)
root.mainloop()

Answer 1

If you design your code so that you pass in the page name as a string rather than as a class then you won't have this problem.
For example, in root.py you can start with something like this:
pages = {
"log in": LIWind,
"sign up": SuWind,
}
Next, in createFrame you would do something like this:
def createFrame(self, page_name):
...
cls = pages[page_name]
newFrame = cls(parent=self.container, controller=self)
...
self.__frames[page_name] = newFrame
Then, anywhere you need the window you can pass in the page name, such as:
self.backBtn = tk.Button(..., command=lambda: controller.showFrame("log in"))