检测键盘输入

Question

我是 Python 的新手，我正在尝试使用键盘库检测何时按下 f 键。这是我正在尝试的代码运行

import keyboard

keyboard.on_press_key('f',here())

def here():
    print('a')

然而，当将 here() 指定为回调时，我在构建时收到名称未定义错误

Answer 1

当你调用here()时，它还没有定义，所以把here()的声明移到你的代码上面。

另外，因为here应该是回调，你需要把它作为函数引用传递给on_press_key。

import keyboard

def here():
    print('a')

keyboard.on_press_key('f', here)

Answer 2

只需向上移动函数 here() 声明，如下所示：

import keyboard

def here():
    print('a')

keyboard.on_press_key('f', here())

否则 here() 尚未声明，因此您的错误。

NameError: global name '---' is not defined Python knows the purposes of certain names (such as names of built-in functions like print). Other names are defined within the program (such as variables). If Python encounters a name that it doesn't recognize, you'll probably get this error. Some common causes of this error include:

Forgetting to give a variable a value before using it in another statement Misspelling the name of a built-in function (e.g., typing "inpit" instead of "input")

对于 python 你的情况下在线时的解释器：

keyboard.on_press_key('f',here())

它不知道 here() 是什么，因为它还不在内存中。

示例：

$ cat test.py 
dummy_call()

def dummy_call():
    print("Foo bar")
$ python test.py 
Traceback (most recent call last):
  File "test.py", line 1, in <module>
    dummy_call()
NameError: name 'dummy_call' is not defined



$ cat test.py 
def dummy_call():
    print("Foo bar")

dummy_call()
$ python test.py 
Foo bar

Answer 3

import keyboard
IsPressed = False

# once you press the button('f') the function happens once
# when you release the button('f') the loop resets

def here():
    print('a')

while True:
    if not keyboard.is_pressed('f'):
        IsPressed = False
    while not IsPressed:
        if keyboard.is_pressed('f'):
            here()
            IsPressed = True

# or if you want to detect every frame it loops then:

def here():
    print('a')

while True:
    if keyboard.is_pressed('f'):
        here()

检测键盘输入

Detecting keyboard input

python

keyboard