CODEWITHSUNDEEP
pythontkinterkey-bindings
Opti Teck
Opti Teck

Reputation: 1

Tkinter key bind don't work with key: "PrintScreen"

im trying to build a "Key-Test" Programm which should show if a key works. (Im from the custom keyboard community)

My code is working fine for "esc" and "F1"-"F12" but with "PrintScreen" it dont work. I don't know why it works with all the other keys and not with printscreen. here is the code snippet from the relevant passage:

from tkinter import *
window = Tk()
c = Canvas(window, width=1135, height=300, bg="lavender")
c.pack()

#Create the rectangle for PrintScreen, ScrollLock and Pause
key13 = c.create_rectangle(772.5, 10, 812.5, 50, fill="white") #PrintScreen
key14 = c.create_rectangle(822.5, 10, 862.5, 50, fill="white") #ScrollLock
key15 = c.create_rectangle(872.5, 10, 912.5, 50, fill="white")  # Pause

#(german) Text for each Key 
text13 = c.create_text(791, 20, text="Druck", font=('Helvetica', '8'))
text14 = c.create_text(841, 20, text="Rollen", font=('Helvetica', '8'))
text15 = c.create_text(891, 20, text="Pause", font=('Helvetica', '8'))

#event functions 
def key_event13(event):
    c.itemconfig(key13, fill="DarkSeaGreen2")


def key_event14(event):
    c.itemconfig(key14, fill="DarkSeaGreen2")


def key_event15(event):
    c.itemconfig(key15, fill="DarkSeaGreen2")


#bind the keys
c.bind_all("<KeyPress-Print>", key_event13)
c.bind_all("<KeyPress-Scroll_Lock>", key_event14)
c.bind_all("<KeyPress-Pause>", key_event15)

window.mainloop()

I already tried to use

c.bind_all("event.keysym_num == 65377", key_event13)

instead of

c.bind_all("<KeyPress-Print>", key_event13)

that doesn't work either...

I hope someone here can help me. Best regards Simon

Upvotes: 0

Views: 461

Answers (1)

Matiiss
Matiiss

Reputation: 6176

I can't tell you why exactly it doesn't work, but you can solve this by using the keyboard module:

pip install keyboard

It has a function for listening to key presses and so you can use that to detect when print screen key is pressed and invoke a callback (so you would use this instead of bind):

keyboard.on_press_key('print screen', key_event13)

So the complete version (without the unnecessary parts) would be:

from tkinter import Tk, Canvas
import keyboard


def key_event13(event):
    # may want to add this since `keyboard` listens to all keyboard events and
    # so even if the window is not in focus it will call this function
    # which these two lines would prevent if needed
    if window.focus_get() is None:
        return
    c.itemconfig(key13, fill="DarkSeaGreen2")
    

window = Tk()

c = Canvas(window, width=1135, height=300, bg="lavender")
c.pack()

key13 = c.create_rectangle(772.5, 10, 812.5, 50, fill="white")
text13 = c.create_text(791, 20, text="Druck", font=('Helvetica', '8'))

keyboard.on_press_key('print screen', key_event13)

window.mainloop()

Obviously for the rest of the keys just use bind.

Also:
I strongly advise against using wildcard (*) when importing something, You should either import what You need, e.g. from module import Class1, func_1, var_2 and so on or import the whole module: import module then You can also use an alias: import module as md or sth like that, the point is that don't import everything unless You actually know what You are doing; name clashes are the issue.

As a side note (my opinion) for organizing your code I would also suggest that you separate functions from the GUI as I have done in my example so that the code is more readable.

Upvotes: 0

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