How to run pynput.Listener simultaneously with tkinter.Tk().mainloop()

问题

I am a teacher. I teach math, but since education is facing human resources crisis, I have some additional duties. I teach kids a bit of programming, they do quite well. Now I'd like to make with them a snake game, but I have a problem achieving multithreading in my GUI app.

I found similar cases but no solutions. Like here: Using the keyboard to move the character in a maze and here: Tkinter.Tk() and threading

def on_press(key):
    print('{0} pressed'.format(key))

def on_release(key):
    if key == Key.esc:
        return False

with Listener(on_press=on_press, on_release=on_release) as listener:
    listener.join()

root = Tk()
root.mainloop()

I expected the window to run simultaneously with the listener. instead, my code listens to the keyboard and then (after I shoot the listener down) pops the window up. it reverses when I call the listener after calling the mainloop, then first the window appears and after I shoot it down the listener is starting to work.

回答1:

You don't need Listener in tkinter. You can use root.bind to assign function to events press and release.

from tkinter import *

def on_press(event):
    #print('on_press: event:', event)
    #print('on_press: keysym:', event.keysym)
    print('{0} pressed'.format(event.keysym))

def on_release(event):
    #print('on_release: event:', event)
    #print('on_release: keysym:', event.keysym)
    print('{0} release'.format(event.keysym))

    if event.keysym == 'Escape':
         print("exist program")
         root.destroy()

root = Tk()

root.bind('<KeyPress>', on_press)
root.bind('<KeyRelease>', on_release)

root.mainloop()

You can also assign function to every key separatelly

from tkinter import *

def on_escape(event):
    print("exist program")
    root.destroy()

root = Tk()

root.bind('<Escape>', on_escape)
#root.bind('<KeyPress-Escape>', on_press_escape)
#root.bind('<KeyRelease-Escape>', on_release_escape)

root.mainloop()

Keysyms in Tcl/Tk documentation: https://www.tcl.tk/man/tcl8.4/TkCmd/keysyms.htm

回答2:

Listener is a thread, so if you join it your main thread will wait until its end to continue processing.

You can just create a Listener object without the with statement and it will run along the main thread (until a callback function will return False)

来源：https://stackoverflow.com/questions/56871975/how-to-run-pynput-listener-simultaneously-with-tkinter-tk-mainloop

标签

python

tkinter

window

listener

pynput