Detecting a keypress in python while in the background

Question

I am trying to find a way to detect a keypress and then run a method depending on what key it is.

I can already do this with Tkinter. But what I can't do is detect the keypress while the window is in the background. I will be running this program in the background while I play a game. I need it to be able to detect inputs while I'm in the game.

Is there any way I can do this with Tkinter or something else? Preferably I would like to not have to download anything external as I would like to distribute this to some other people.

Answer 1

Too get all the properties from your key press event. you can do the following

import pythoncom, pyHook

def OnKeyboardEvent(event):
    print('MessageName:',event.MessageName)
    print('Message:',event.Message)
    print('Time:',event.Time)
    print('Window:',event.Window)
    print('WindowName:',event.WindowName)
    print('Ascii:', event.Ascii, chr(event.Ascii))
    print('Key:', event.Key)
    print('KeyID:', event.KeyID)
    print('ScanCode:', event.ScanCode)
    print('Extended:', event.Extended)
    print('Injected:', event.Injected)
    print('Alt', event.Alt)
    print('Transition', event.Transition)
    print('---')

# return True to pass the event to other handlers
    return True

# create a hook manager
hm = pyHook.HookManager()
# watch for all mouse events
hm.KeyDown = OnKeyboardEvent
# set the hook
hm.HookKeyboard()
# wait forever
pythoncom.PumpMessages()

Now know all the details of the key press and do operation on top of this.

pressing 's' would look like this

MessageName: key down
Message: 256
Time: 449145375
Window: 2558060
WindowName: "file name"
Ascii: 115 s
Key: S
KeyID: 83
ScanCode: 31
Extended: 0
Injected: 0
Alt 0
Transition 0

Answer 2

pyHook seems like it would work well for this (mentioned by furas)

from pyHook import HookManager
from win32gui import PumpMessages, PostQuitMessage

class Keystroke_Watcher(object):
    def __init__(self):
        self.hm = HookManager()
        self.hm.KeyDown = self.on_keyboard_event
        self.hm.HookKeyboard()


    def on_keyboard_event(self, event):
        try:
            if event.KeyID  == keycode_youre_looking_for:
                self.your_method()
        finally:
            return True

    def your_method(self):
        pass

    def shutdown(self):
        PostQuitMessage(0)
        self.hm.UnhookKeyboard()


watcher = Keystroke_Watcher()
PumpMessages()