在python中轮询键盘(检测按键)

Question

如何从控制台python应用程序轮询键盘？具体来说,我想在许多其他I/O活动(套接字选择,串行端口访问等)中做类似的事情:

   while 1:
      # doing amazing pythonic embedded stuff
      # ...

      # periodically do a non-blocking check to see if
      # we are being told to do something else
      x = keyboard.read(1000, timeout = 0)

      if len(x):
          # ok, some key got pressed
          # do something

在Windows上执行此操作的正确pythonic方法是什么？此外,Linux的可移植性也不错,但并不是必需的.

Answer 1

标准方法是使用选择模块.

但是,这在Windows上不起作用.为此,您可以使用msvcrt模块的键盘轮询.

通常,这是通过多个线程完成的 - 每个设备被"监视"一个加上可能需要被设备中断的后台进程.

Answer 2

import sys
import select

def heardEnter():
    i,o,e = select.select([sys.stdin],[],[],0.0001)
    for s in i:
        if s == sys.stdin:
            input = sys.stdin.readline()
            return True
    return False

Answer 3

使用curses模块的解决方案.打印与按下的每个键对应的数值:

import curses

def main(stdscr):
    # do not wait for input when calling getch
    stdscr.nodelay(1)
    while True:
        # get keyboard input, returns -1 if none available
        c = stdscr.getch()
        if c != -1:
            # print numeric value
            stdscr.addstr(str(c) + ' ')
            stdscr.refresh()
            # return curser to start position
            stdscr.move(0, 0)

if __name__ == '__main__':
    curses.wrapper(main)

Answer 4

好吧,既然我试图在评论中发布我的解决方案失败了,这就是我想说的.我可以使用以下代码完成我想要的原生Python(在Windows上,而不是其他任何地方):

import msvcrt 

def kbfunc(): 
   x = msvcrt.kbhit()
   if x: 
      ret = ord(msvcrt.getch()) 
   else: 
      ret = 0 
   return ret

Answer 5

这些答案都不适合我.这个包pynput完全符合我的需要.

https://pypi.python.org/pypi/pynput

from pynput.keyboard import Key, Listener

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

def on_release(key):
    print('{0} release'.format(
        key))
    if key == Key.esc:
        # Stop listener
        return False

# Collect events until released
with Listener(
        on_press=on_press,
        on_release=on_release) as listener:
    listener.join()

Answer 6

你可能会看看pygame如何处理这个以窃取一些想法.

Answer 7

来自评论:

import msvcrt # built-in module

def kbfunc():
    return ord(msvcrt.getch()) if msvcrt.kbhit() else 0

谢谢您的帮助.我最终编写了一个名为PyKeyboardAccess.dll的C DLL并访问了crt conio函数,导出了这个例程:

#include <conio.h>

int kb_inkey () {
   int rc;
   int key;

   key = _kbhit();

   if (key == 0) {
      rc = 0;
   } else {
      rc = _getch();
   }

   return rc;
}

我使用ctypes模块(内置到python 2.5中)在python中访问它:

import ctypes
import time

#
# first, load the DLL
#


try:
    kblib = ctypes.CDLL("PyKeyboardAccess.dll")
except:
    raise ("Error Loading PyKeyboardAccess.dll")


#
# now, find our function
#

try:
    kbfunc = kblib.kb_inkey
except:
    raise ("Could not find the kb_inkey function in the dll!")


#
# Ok, now let's demo the capability
#

while 1:
    x = kbfunc()

    if x != 0:
        print "Got key: %d" % x
    else:
        time.sleep(.01)

Answer 8

我kbhit在http://home.wlu.edu/~levys/software/kbhit.py 上遇到了一个跨平台的实现（进行了编辑以删除不相关的代码）：

import os
if os.name == 'nt':
    import msvcrt
else:
    import sys, select

def kbhit():
    ''' Returns True if a keypress is waiting to be read in stdin, False otherwise.
    '''
    if os.name == 'nt':
        return msvcrt.kbhit()
    else:
        dr,dw,de = select.select([sys.stdin], [], [], 0)
        return dr != []

确保read()等待的字符 - 该函数将一直返回，True直到您这样做为止！