Can’t get .desktop file to run python script

Question

EDIT 9: Before writing an answer saying to change Exec=/home/insertUsernameHere/volumeGUI/volumeGUI.py to Exec=something or another, the .desktop file Exec= code isn't the problem as it runs fine with gtk-launch. The problem is that it doesn't run from Show Applications, it just does nothing. Also please watch my screen capture so you can see exactly what the problem is.

I’ve been trying (for a couple of hours now) to get a .desktop file to run my python script, but when I click on the icon in the applications window, nothing happens.

Here’s my .desktop code:

[Desktop Entry]
Encoding=UTF-8
Version=1.0
Type=Application
Terminal=false
Exec=/home/insertUsernameHere/volumeGUI/volumeGUI.py
Name=Volume GUI
Icon=/home/insertUsernameHere/volumeGUI/volumeGUI_Logo.png

Note that when I run /home/insertUsernameHere/volumeGUI/volumeGUI.py in the terminal it works fine.

EDIT: Here's my python code

#!/usr/bin/env python3

from tkinter import *
from tkinter.font import *
import subprocess

top = Tk()
top.resizable(False, False)
top.title("Python Volume Controller")
padx = 10
pady = 10
myFont = Font(family = "helvetica", size = 16, weight = "bold")

volumeTextVariable = StringVar()
currentVolumeText = Label(top, textvariable = volumeTextVariable, font = myFont)
currentVolumeText.grid(row = 1, column = 0, columnspan = 2, padx=padx, pady=pady)

volumeIncrement = 2

def volumeUp(volume):
    if (volume + volumeIncrement) <= 100:
        subprocess.call("pactl set-sink-volume 0 +" + str(volumeIncrement) + r"%", shell=True)
        volumeTextVariable.set("Current Volume: " + getVolume() + r"%")

def volumeDown(volume):
    if (volume - volumeIncrement) >= 0:
        subprocess.call("pactl set-sink-volume 0 -" + str(volumeIncrement) + r"%", shell=True)
        volumeTextVariable.set("Current Volume: " + getVolume() + r"%")

def getVolume():
    try:
        volume = subprocess.Popen("amixer get Master |grep % |awk '{print $4}'|sed 's/[^0-9]//g'", stdout=subprocess.PIPE, shell=True).communicate()[0].decode("utf-8")[:-1]
    except:
        volume = -404
    return volume

volumeTextVariable.set("Current Volume: " + getVolume() + r"%")

volUpButton = Button(top, text = "Volume Up", command = lambda: volumeUp(int(getVolume())), font = myFont)
volDownButton = Button(top, text = "Volume Down", command = lambda: volumeDown(int(getVolume())), font = myFont)
volUpButton.grid(row = 2, column = 1, padx=padx, pady=pady)
volDownButton.grid(row = 2, column = 0, padx=padx, pady=pady)

top.mainloop()

EDIT 6: GIF of me running the .desktop file in the command line with gtk-launch volumeGUI.desktop and it working, but not working when trying to launch it from Show Applications
Screen Capture

EDIT 7: I have since improved my python code: https://paste.ubuntu.com/p/QF6PVrSPSy/

EDIT 8: I changed Exec=/home/insertUsernameHere/volumeGUI/volumeGUI.py to Exec=bash -c "/home/insertUsernameHere/volumeGUI/volumeGUI.py 2>&1 > ~/logfile.txt" as per a suggestion and when I either run it with gtk-launch or try and run it from Show Applications the log file is empty.

Answer 1

Try changing Exec=/script.py to Exec=python3 /script.py

I have several Java programs that I run via .desktop files. Some even get executed on boot... Sorry so short, posting via my phone.