Why can I not show a TopLevel window after launching the FileDialog module?
I would like to show a window with a waiting message after executing FileDialog code.
If I create the
TopLevelwindow before callingFileDialog, the window is displayed and then theFileDialogcode is executed.But if I run
FileDialogfirst, then create theTopLevel, this window is not displayed.
This code works fine:
import time
from tkinter import filedialog
from tkinter import *
root = Tk()
root.title("Main window")
root.geometry("400x200")
topLevelWindow = Toplevel(root)
topLevelWindow.title("Secondary window")
topLevelWindow.geometry("400x200")
Label(topLevelWindow, text="Plaese wait...").pack()
# Choose a file and save the path
filename = filedialog.askopenfilename(initialdir = "/",title = "Select file",filetypes = [("All files", "*.*")])
print("File path: ", filename)
But if I execute TopLevel code after FileDialog, it does not show the TopLevel window:
import time
from tkinter import filedialog
from tkinter import *
root = Tk()
root.title("Main window")
root.geometry("400x200")
# Choose a file and save the path
filename = filedialog.askopenfilename(initialdir = "/",title = "Select file",filetypes = [("All files", "*.*")])
topLevelWindow = Toplevel(root)
topLevelWindow.title("Secondary window")
topLevelWindow.geometry("400x200")
Label(topLevelWindow, text="Plaese wait...").pack()
print("File path: ", filename)
Thanks in advance for any help!
I wish to launch TopLevel windows after the FileDialog execution.
Answer
The filedialog.askopenfilename() blocks the main thread with its own event loop; After it closes, the Toplevel is created but not rendered immediately.
To reliably launch a Toplevel window after a filedialog.askopenfilename() call, you must ensure that Tk() window and mainloop() are running, and call the fileDialog inside an event callback.
Something like this should work:
from tkinter import filedialog, Toplevel, Label, Button, Tk
def open_file_and_show_window():
filename = filedialog.askopenfilename(
title="Select a file",
filetypes=[("All files", "*.*")]
)
print("Selected file:", filename)
top = Toplevel(root)
top.title("Processing Window")
top.geometry("300x100")
Label(top, text="Please wait...").pack(pady=20)
root = Tk()
root.title("Main Window")
root.geometry("400x200")
Button(root, text="Choose File", command=open_file_and_show_window).pack(pady=50)
root.mainloop()