问题

我正在尝试创建一个反应时间游戏，但是在添加热键后，当我按下回车键时，出现了一个超长的NoneType错误，涉及到多个不同的文件。

```python
import time
import datetime
import random
import keyboard

playing = True

def stop(playing):
    playing = False

input("按下回车键开始测试您的反应时间！")
print("当您看到猫时，请按回车键！")

time.sleep(1)

keyboard.add_hotkey('enter', stop(playing))

time.sleep(random.randint(3, 6))

if playing == True:
    keyboard.remove_hotkey('enter')
    start = datetime.datetime.now()
    input("按回车键!!!!")
    end = datetime.datetime.now()
    print(end - start)

热键的目的是阻止用户仅仅按住回车键不放。我不知道为什么这不起作用。

我尝试在函数的末尾添加'return playing'，但这只会给我一个类似'bool is not callable'的错误。

<details>
<summary>英文:</summary>

I&#39;m trying to create a reaction time game thing, however when I press enter after the hotkey is added I get a super long Nonetype error making reference to several different files.

import time
import datetime
import random
import keyboard

playing=True

def stop(playing):
playing=False

input("Press enter when you're ready to test your reaction time!")
print("Press enter when you see the cat!")

time.sleep(1)

keyboard.add_hotkey('enter', stop(playing))

time.sleep(random.randint(3,6))

if(playing==True):
keyboard.remove_hotkey('enter')
start = datetime.datetime.now()
input("Press Enter!!!!")
end = datetime.datetime.now()
print(end-start)

The idea of the hotkey is to stop the user from being able to just hold the enter button down. I don't know why this doesn't work. 

I tried adding 'return playing' to the end of the function but that just gave me a similar error of 'bool is not callable'

</details>


# 答案1
**得分**: 0

The code you provided can be translated as follows:

```plaintext
`stop(playing)` 返回 `None`，所以当你这样做时：

```python
keyboard.add_hotkey('enter', stop(playing))

就等同于你这样做：

stop(playing)
keyboard.add_hotkey('enter', None)

add_hotkey 的第二个参数应该是一个函数（而不是调用一个函数的结果），所以如果你传递 None，它会引发错误。

我认为你想要做的是定义你的 stop 函数，使它可以不带参数调用，并将全局变量 playing 设置为 False：

def stop():
    global playing
    playing = False

然后将该函数（不要立即调用它）传递给 add_hotkey：

keyboard.add_hotkey('enter', stop)

<details>
<summary>英文:</summary>

`stop(playing)` returns `None`, so when you do:

keyboard.add_hotkey('enter', stop(playing))

it's exactly as if you did:

stop(playing)
keyboard.add_hotkey('enter', None)

The second argument to `add_hotkey` is supposed to be a function (not the result of calling a function), so if you pass it `None`, it raises an error.

What I think you want to do is define your `stop` function so that it can be called with no arguments, and sets the global `playing` variable to False:

def stop()
global playing
playing = False

and then pass the function (without calling it yet) to `add_hotkey`:

keyboard.add_hotkey('enter', stop)

</details>



# 答案2
**得分**: 0

This prematurely **calls** the `stop` function and then passes `None` as the callback argument to `add_hotkey`. Then when the event is triggered `None` it is being attempted to be called.

Instead, you should use

```python
keyboard.add_hotkey('enter', stop, args=(playing,))

as shown on the documentation.

keyboard.add_hotkey('enter', stop(playing))

keyboard.add_hotkey('enter', stop, args=(playing,))