Python脚本未在sys.exit（）上停止

Question

我编写了一个脚本，通过相应地移动鼠标，可以从ScalableVectorGraphics（.svg）中绘制多段线（it over on github）

当您将鼠标控制权交给脚本时，killswitch肯定是必要的，因此我在Internet上找到了一个键盘侦听器示例：

def on_press(key):
try:
    sys.exit()
    print('alphanumeric key {0} pressed'.format(key.char))
    print('adsfadfsa')
except AttributeError:
    print('special key {0} pressed'.format(
        key))

def main():
listener = keyboard.Listener( #TODO fix sys.exit()
    on_press=on_press)
listener.start()

if __name__ == '__main__':
main()

它似乎在工作：如果我在sys.exit（）之前添加一个print语句，它会立即正确执行。 但是使用sys.exit（）时，我的鼠标一直在移动，python解释器仍然在Taskmanager上。我不知道为什么它一直在执行

提前感谢您的建议。 斯莫尔先生

解决方案是：操作系统。\u退出（1）

完整源代码：

from pynput import mouse as ms
from pynput import keyboard
from pynput.mouse import Button, Controller
import threading
import time
from xml.dom import minidom
import re

sys.path.append('/Users/MrSmoer/Desktop/linedraw-master')

mouse = ms.Controller()
tlc = None
brc = None
brc_available = threading.Event()

biggestY = 0
biggestX = 0

drwblCnvsX = 0
drwblCnvsY = 0


def on_click(x, y, button, pressed):
    if not pressed:
        # Stop listener
        return False


def on_press(key):
    try:
        sys.exit()
        print('alphanumeric key {0} pressed'.format(key.char))
        print('adsfadfsa')
    except AttributeError:
        print('special key {0} pressed'.format(
            key))


def initialize():
    print("Please select your programm and then click at the two corners of the canvas. Press any key to cancel.")
    with ms.Listener(
            on_click=on_click) as listener:
        listener.join()

    print('please middleclick, when you are on top left corner of canvas')
    with ms.Listener(
            on_click=on_click) as listener:
        listener.join()

    global tlc
    tlc = mouse.position

    print('please middleclick, when you are on bottom left corner of canvas')
    with ms.Listener(
            on_click=on_click) as listener:
        listener.join()
    global brc
    brc = mouse.position
    mouse.position = tlc
    print('thread finished')
    brc_available.set()


def getDrawabableCanvasSize(polylines):
    global biggestX
    global biggestY

    for i in range(len(polylines)):  # goes throug all polylines
        points = hyphen_split(polylines[i])  # Splits polylines to individual points
        for c in range(len(points)):  # goes throug all points on polyline
            cord = points[c].split(',')  # splits points in x and y axis
            if float(cord[0]) > (biggestX - 5):
                biggestX = float(cord[0]) + 5
            if float(cord[1]) > (biggestY - 5):
                biggestY = float(cord[1]) + 5
    print('TLC: ', tlc)
    print('bigX: ', biggestX)
    print('bigY: ', biggestY)

    cnvswidth = tuple(map(lambda i, j: i - j, brc, tlc))[0]
    cnvsheight = tuple(map(lambda i, j: i - j, brc, tlc))[1]
    cnvsapr = cnvswidth / cnvsheight
    print('Canvasaspr: ', cnvsapr)
    drwblcnvaspr = biggestX / biggestY
    print('drwnble aspr: ', drwblcnvaspr)

    if drwblcnvaspr < cnvsapr:  # es mus h vertikal saugend
        print('es mus h vertikal saugend')
        finalheight = cnvsheight
        finalwidth = finalheight * drwblcnvaspr

    else:  # es muss horizontal saugend, oder aspect ratio ist eh gleich
        print('es muss horizontal saugend, oder aspect ratio ist eh gleich')
        finalwidth = cnvswidth
    scalefactor = finalwidth / biggestX
    print(scalefactor)
    return scalefactor


def drawPolyline(polyline, scalefactor):
    points = hyphen_split(polyline)
    #print(points)
    beginpoint = tlc
    for c in range(len(points)):  # goes throug all points on polyline
        beginpoint = formatPoint(points[c], scalefactor)
        if len(points) > c + 1:
            destpoint = formatPoint(points[c + 1], scalefactor)
            mouse.position = beginpoint
            time.sleep(0.001)
            mouse.press(Button.left)
            # time.sleep(0.01)
            mouse.position = destpoint
            # time.sleep(0.01)
            mouse.release(Button.left)
        else:
            destpoint = tlc
            #print("finished line")
    mouse.release(Button.left)


def formatPoint(p, scale):
    strcord = p.split(',')
    #print(scale)
    #print(tlc)
    x = float(strcord[0]) * scale + tlc[0]  # + drwblCnvsX/2
    y = float(strcord[1]) * scale + tlc[1]  # + drwblCnvsY/2
    #print('x: ', x)
    #print('y: ', y)
    thistuple = (int(x), int(y))
    return thistuple


def hyphen_split(a):
    return re.findall("[^,]+\,[^,]+", a)
    # ['id|tag1', 'id|tag2', 'id|tag3', 'id|tag4']


def main():
    listener = keyboard.Listener( #TODO fix sys.exit()
        on_press=on_press)
    listener.start()

    thread = threading.Thread(target=initialize()) #waits for initializing function (two dots)
    thread.start()
    brc_available.wait()

   # print(sys.argv[1])
    doc = minidom.parse('/Users/MrSmoer/Desktop/linedraw-master/output/out.svg')  # parseString also exists
    try:
        if sys.argv[1] == '-ip':
            doc = minidom.parse(sys.argv[2])
    except IndexError:
        print('Somethings incorrect1')

    polylines = NotImplemented

    try:
        doc = minidom.parse('/Users/MrSmoer/Desktop/linedraw-master/output/out.svg')  # parseString also exists
        # /Users/MrSmoer/Desktop/linedraw-master/output/output2.svg
        #doc = minidom.parse('/Users/MrSmoer/Desktop/Test.svg')
        polylines = [path.getAttribute('points') for path
                     in doc.getElementsByTagName('polyline')]
        doc.unlink()
    except:
        print('Somethings incorrect3')

    # print(polylines)

    scalefactor = getDrawabableCanvasSize(polylines)

    for i in range(len(polylines)):
        drawPolyline(polylines[i], scalefactor)


if __name__ == '__main__':
    main()

Answer 1

sys.exit()最终会杀死正在执行它的线程，但您的程序似乎利用了多个线程

如果要退出，您需要杀死程序的所有线程，包括主线程

Answer 2

有时，在编写多线程应用程序时，raise SystemExit和sys.exit（）都只杀死正在运行的线程。另一方面，os._exit（）退出整个过程

虽然您通常更喜欢sys.exit，因为它比其他代码更“友好”，但它实际上只会引发一个异常

如果您确定需要立即退出某个进程，并且您可能在某个异常处理程序中，该异常处理程序将捕获SystemExit，那么还有另一个函数-os.\U exit-将立即在C级别终止，并且不会执行任何正常的解释器分解

提前终止Python脚本的一种简单方法是使用内置的quit（）函数。无需导入任何库，而且效率高且简单

例如：

       #do stuff
     if this == that:
      quit()

你可以试试这些选项！！ 希望它能正常工作！！如果不告诉我们，我们将尝试更多的解决方案