python如何监听按键推出无限循环?
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有个无限循环显示A,当监听到按键esc,就跳出这个无限循环,显示B。请问怎么写?
#!/usr/bin/python3
import keyboard
import time
while true:
print("A")
time.sleep(1)
print("B")
keyboard.wait("esc")
请善用官方文档keyboard pypi主页keyboard github主页
python 在windows下监听键盘按键
python 在windows下监听键盘按键
使用到的库
- ctypes(通过ctypes来调用Win32API, 主要就是调用钩子函数)
使用的Win32API
- SetWindowsHookEx(), 将用户定义的钩子函数添加到钩子链中, 也就是我们的注册钩子函数
- UnhookWindowsHookEx(), 卸载钩子函数
- CallNextHookEx()在我们的钩子函数中必须调用, 这样才能让程序的传递消息
在没有钩子函数的情况下windows程序运行机制
- 键盘输入 --> 系统消息队列 --> 对应应用程序的消息队列 --> 将消息发送到对应的窗口中
在有了钩子函数的情况下windows程序运行机制
- 键盘输入 --> 系统消息队列 --> 对应应用程序消息队列 --> 将消息发送到钩子链中 --> 消息一一调用完毕所有的钩子函数(需要调用CallNextHookEx函数才能将消息传递下去) --> 将消息发送到对应的窗口中
示例程序
- 注意:
- 在程序中, 我们通过CFUNCTYPE返回一个类对象, 通过该类对象可以实例化出我们需要的c类型的函数, 但是如果不将他放在全局的话则会失去效果, 因为在C语言中函数是全局的
# -*- coding: utf-8 -*-
import os
import sys
from ctypes import *
from ctypes.wintypes import *
"""
define constants
"""
WH_KEYBOARD = 13
WM_KEYDOWN = 0x0100
CTRL_CODE = 162
class JHKeyLogger(object):
def __init__(self, user32, kernel32):
"""
Description:
Init the keylogger object, the property ‘hook_‘ is the handle to control our hook function
Args:
@(dll)user32: just put windll.user32 here
@(dll)kernel32: just put windll.kernel32 here
Returns:
None
"""
self.user32_ = user32
self.kernel32_ = kernel32
self.hook_ = None
def install_hookproc(self, hookproc):
"""
Description:
install hookproc function into message chain
Args:
@(c type function)hookproc: hookproc is the hook function to call
Returns:
@(bool):
if SetWindowHookExA() function works successfully, return True
else return False
"""
self.hook_ = self.user32_.SetWindowsHookExA(
WH_KEYBOARD,
hookproc,
self.kernel32_.GetModuleHandleW(None),
0)
if not self.hook_:
return False
return True
def uninstall_hookproc(self):
"""
Description:
uninstall the hookproc function which means pick the hookproc pointer off the message chain
Args:
None
Returns:
None
"""
if not self.hook_:
return
self.user32_.UnhookWindowsHookEx(self.hook_)
self.hook_ = None
def start(self):
"""
Description:
start logging, just get the message, the current thread will blocked by the GetMessageA() function
Args:
None
Returns:
None
"""
msg = MSG()
self.user32_.GetMessageA(msg, 0, 0, 0)
def stop(self):
self.uninstall_hookproc()
def hookproc(nCode, wParam, lParam):
"""
Description:
An user-defined hook function
Attention:
here we use the global variable named ‘g_keylogger‘
"""
if wParam != WM_KEYDOWN:
return g_keylogger.user32_.CallNextHookEx(g_keylogger.hook_, nCode, wParam, lParam)
pressed_key = chr(lParam[0])
print pressed_key,
# hit ctrl key to stop logging
if CTRL_CODE == lParam[0]:
g_keylogger.stop()
sys.exit(-1)
return g_keylogger.user32_.CallNextHookEx(g_keylogger.hook_, nCode, wParam, lParam)
# Attention: pointer must be defined as a global variable
cfunctype = CFUNCTYPE(c_int, c_int, c_int, POINTER(c_void_p))
pointer = cfunctype(hookproc)
g_keylogger = JHKeyLogger(windll.user32, windll.kernel32)
def main():
if g_keylogger.install_hookproc(pointer):
print ‘install keylogger successfully!‘
g_keylogger.start()
print ‘hit ctrl to stop‘
if __name__ == ‘__main__‘:
main()
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