Tkinter Show splash screen and hide main screen until __init__ has finished

Question

I have a main tkinter window that can take up to a few seconds to load properly. Because of this, I wish to have a splash screen that shows until the init method of the main class has finished, and the main tkinter application can be shown. How can this be achieved?

Splash screen code:

from Tkinter import *
from PIL import Image, ImageTk
import ttk

class DemoSplashScreen: 
    def __init__(self, parent): 
        self.parent = parent 
        self.aturSplash() 
        self.aturWindow() 

    def aturSplash(self): 
        self.gambar = Image.open('../output5.png')
        self.imgSplash = ImageTk.PhotoImage(self.gambar)

    def aturWindow(self):
        lebar, tinggi = self.gambar.size 
        setengahLebar = (self.parent.winfo_screenwidth()-lebar)//2 
        setengahTinggi = (self.parent.winfo_screenheight()-tinggi)//2
        self.parent.geometry("%ix%i+%i+%i" %(lebar, tinggi, setengahLebar,setengahTinggi))
        Label(self.parent, image=self.imgSplash).pack()


if __name__ == '__main__': 
    root = Tk()
    root.overrideredirect(True) 
    progressbar = ttk.Progressbar(orient=HORIZONTAL, length=10000, mode='determinate') 
    progressbar.pack(side="bottom") 
    app = DemoSplashScreen(root) 
    progressbar.start()
    root.after(6010, root.destroy) 
    root.mainloop()

Main tkinter window minimum working example:

import tkinter as tk

root = tk.Tk()

class Controller(tk.Frame):
    def __init__(self, parent):
        '''Initialises basic variables and GUI elements.'''
        frame = tk.Frame.__init__(self, parent,relief=tk.GROOVE,width=100,height=100,bd=1)

control = Controller(root)
control.pack()
root.mainloop()

EDIT: I can use the main window until it has finished loading using the .withdraw() and .deiconify() methods. However my problem is that I cannot find a way to have the splash screen running in the period between these two method calls.

Answer 1

a simple example for python3:

#!python3

import tkinter as tk
import time

class Splash(tk.Toplevel):
    def __init__(self, parent):
        tk.Toplevel.__init__(self, parent)
        self.title("Splash")

        ## required to make window show before the program gets to the mainloop
        self.update()

class App(tk.Tk):
    def __init__(self):
        tk.Tk.__init__(self)
        self.withdraw()
        splash = Splash(self)

        ## setup stuff goes here
        self.title("Main Window")
        ## simulate a delay while loading
        time.sleep(6)

        ## finished loading so destroy splash
        splash.destroy()

        ## show window again
        self.deiconify()

if __name__ == "__main__":
    app = App()
    app.mainloop()

one of the reasons things like this are difficult in tkinter is that windows are only updated when the program isn't running particular functions and so reaches the mainloop. for simple things like this you can use the update or update_idletasks commands to make it show/update, however if the delay is too long then on windows the window can become "unresponsive"

one way around this is to put multiple update or update_idletasks command throughout your loading routine, or alternatively use threading.

however if you use threading i would suggest that instead of putting the splash into its own thread (probably easier to implement) you would be better served putting the loading tasks into its own thread, keeping worker threads and GUI threads separate, as this tends to give a smoother user experience.