PyQt5.QtWidgets causes problems with backspace in tkinter entry line

Question

I have already tried to find an answer to my question, but I haven't been successful.

I do my first try with an GUI with tkinter on Python 3.6

I create a small example for you:

import tkinter as tk
import PyQt5.QtWidgets

RateFenstergrossh=0.75
RateFenstergrossb=0.75

app = PyQt5.QtWidgets.QApplication([])  # the bug doesn't occur without this line 
screen_width = app.desktop().screenGeometry().width()
screen_height = app.desktop().screenGeometry().height()

def vp_start_gui():
    global root
    root = tk.Tk()
    top = Toplevel1(root)
    root.mainloop()

class Toplevel1:
    def __init__(self, top=None):
        top.geometry("+%d+%d"%(screen_width/2 - screen_width*RateFenstergrossb/2, screen_height/2 - screen_height*RateFenstergrossh/2))

        self.Entry = tk.Entry(top)
        self.Entry.pack(padx=20,pady=20)

if __name__ == '__main__':
    vp_start_gui()

If you type some characters and try to delete them with backspace a small rectangle appears in the entry line. If you print this character the program prints <0x08>. If I do not use the package import PyQt5.QtWidgets and the funktion PyQt5.QtWidgets.QApplication([]) the bug doesn't occur.

I do not really understand this bug. Maybe somebody can help me with this.

Why are you trying to use both Tkinter and Qt in one program? Those are two entirely separate approaches to writing GUIs. — jasonharper, Mar 17 '20 at 20:44
***"not use PyQt5 ... the bug doesn't occur."***: That's the reason **not** to do so. Why have you choosen to mix this two modules? — stovfl, Mar 17 '20 at 20:53
I tried this because I found this solution to center the windows at https://stackoverflow.com/questions/3352918/how-to-center-a-window-on-the-screen-in-tkinter — Zaby1990, Mar 17 '20 at 21:18
Maybe if you understand the problem, you do know a better solution to center the window on screen or to read the screen size without PyQt5 — Zaby1990, Mar 17 '20 at 21:24

Zaby1990 · Accepted Answer · 2020-03-17T21:50:06.210

Thanks to the two comments. I have learned never mix tkinter and PyQt. My solution is now.

import tkinter as tk

RateFenstergrossh=0.75
RateFenstergrossb=0.75

def vp_start_gui():
    global root
    root = tk.Tk()
    screen_width = root.winfo_screenwidth()
    screen_height = root.winfo_screenheight()
    top = Toplevel1(root)
    root.mainloop()

class Toplevel1:
    def __init__(self, top=None):
        top.geometry("+%d+%d"%(screen_width/2 - screen_width*RateFenstergrossb/2, screen_height/2 - screen_height*RateFenstergrossh/2))

        self.Entry = tk.Entry(top)
        self.Entry.pack(padx=20,pady=20)

if __name__ == '__main__':
    vp_start_gui()

Solution: I have to read the screensize with

screen_width = root.winfo_screenwidth()
screen_height = root.winfo_screenheight()

PyQt5.QtWidgets causes problems with backspace in tkinter entry line

1 Answers1