PyCharm关闭后仍显示正在运行的脚本

Question

今天我注意到一个在Windows 10上运行的Python脚本在PyCharm 2020.2 IDE中，当我点击X退出时，主窗口消失了，但PyCharm仍显示一个正在运行的脚本的图标。在PyCharm中明确终止脚本后，会出现以下错误消息。

Process finished with exit code -1

当我在Linux（Ubuntu）上执行PyCarm IDE中的脚本时，点击X退出主窗口后，PyCharm不会显示正在运行的脚本的图标。为什么会这样呢？

代码：

import sys
from datetime import datetime
import pythoncom

import wmi

from PyQt5. QtCore import QObject, QRunnable, QThreadPool, pyqtSignal
from PyQt5.QtWidgets import QApplication, QMainWindow, QTableWidget, QTableWidgetItem, QHeaderView


class KeyboardDetectorSignals(QObject):
    keyboard_changed = pyqtSignal(str)


class KeyboardDetector(QRunnable):

    def __init__(self):
        super().__init__()

        self.signals = KeyboardDetectorSignals()

    def run(self):
        pythoncom.CoInitialize()
        device_connected_wql = "SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"
        device_disconnected_wql = "SELECT * FROM __InstanceDeletionEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"

        c = wmi.WMI()
        connected_watcher = c.watch_for(raw_wql=device_connected_wql)
        disconnected_watcher = c.watch_for(raw_wql=device_disconnected_wql)

        while True:
            try:
                connected = connected_watcher(timeout_ms=10)
            except wmi.x_wmi_timed_out:
                pass
            else:
                if connected:
                    self.signals.keyboard_changed.emit("Keyboard connected.")

            try:
                disconnected = disconnected_watcher(timeout_ms=10)
            except wmi.x_wmi_timed_out:
                pass
            else:
                if disconnected:
                    self.signals.keyboard_changed.emit("Keyboard disconnected.")


class MainWindow(QMainWindow):

    def __init__(self):
        super().__init__()

        self.setGeometry(100, 100, 500, 500)
        self.setWindowTitle("Keyboard Logger")

        self.log_table = QTableWidget()
        self.log_table.setColumnCount(2)
        self.log_table.setShowGrid(True)
        self.log_table.setHorizontalHeaderLabels(["Time", "Event"])
        self.log_table.horizontalHeader().setStretchLastSection(True)
        self.log_table.horizontalHeader().setSectionResizeMode(QHeaderView.ResizeToContents)
        self.setCentralWidget(self.log_table)
        self.show()

        self.threadpool = QThreadPool()
        keyboard_detector = KeyboardDetector()
        keyboard_detector.signals.keyboard_changed.connect(self.add_row)
        self.threadpool.start(keyboard_detector)

    def add_row(self, event: str):
        now = datetime.now()
        datetime_string = now.strftime("%Y-%m-%d %H:%M:%S")

        row_count = self.log_table.rowCount()
        self.log_table.insertRow(row_count)
        self.log_table.setItem(row_count, 0, QTableWidgetItem(datetime_string))
        self.log_table.setItem(row_count, 1, QTableWidgetItem(event))


def main():
    app = QApplication(sys.argv)
    window = MainWindow()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

- Atalanttore

---

当你从命令提示符/终端运行脚本时会发生什么？在关闭QT窗口后，脚本是否仍在运行？ - Asaf Amnony

关闭Qt窗口后，脚本会在后台继续运行。命令提示符/终端在窗口关闭后也不接受新命令。 - Atalanttore

Answer 1

请注意，Process finished with exit code -1 并不是错误，它只是意味着您的程序已终止。

- user14246674

---

退出代码（0）表示无错误或问题的退出。退出代码（1）表示存在某些问题/故障导致程序退出。每个代码的影响可能因操作系统而异，但在Python中应该是相当一致的。 - Jatin Mehrotra

据我所知，Python在成功运行时会返回退出码0，否则它将返回退出码1。而其他程序在成功返回退出码0或者在失败时返回非0的退出码。 - user14246674

Answer 2

我不确定，但在代码的结尾你可以尝试写 exit(1)

- Manu Sampablo

---

遗憾的是，在关闭Qt窗口之后，带有exit(1)的脚本仍然在后台运行。 - Atalanttore

Answer 3

友好的Reddit用户Lolslim终于解决了这个问题。

他修改的代码如下：

import sys
from datetime import datetime
import pythoncom

import wmi

from PyQt5. QtCore import QObject, QRunnable, QThreadPool, pyqtSignal
from PyQt5.QtWidgets import QApplication, QMainWindow, QTableWidget, QTableWidgetItem, QHeaderView


class KeyboardDetectorSignals(QObject):
    keyboard_changed = pyqtSignal(str)


class KeyboardDetector(QRunnable):

    def __init__(self):
        super().__init__()
        self._stop = False
        self.signals = KeyboardDetectorSignals()


    def stop(self):
        self._stop = True


    def run(self):
        pythoncom.CoInitialize()
        device_connected_wql = "SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"
        device_disconnected_wql = "SELECT * FROM __InstanceDeletionEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"

        c = wmi.WMI()
        connected_watcher = c.watch_for(raw_wql=device_connected_wql)
        disconnected_watcher = c.watch_for(raw_wql=device_disconnected_wql)

        while not self._stop:
            try:
                connected = connected_watcher(timeout_ms=10)
            except wmi.x_wmi_timed_out:
                pass
            else:
                if connected:
                    self.signals.keyboard_changed.emit("Keyboard connected.")

            try:
                disconnected = disconnected_watcher(timeout_ms=10)
            except wmi.x_wmi_timed_out:
                pass
            else:
                if disconnected:
                    self.signals.keyboard_changed.emit("Keyboard disconnected.")


class MainWindow(QMainWindow):

    def __init__(self):
        super().__init__()

        self.setGeometry(100, 100, 500, 500)
        self.setWindowTitle("Keyboard Logger")

        self.log_table = QTableWidget()
        self.log_table.setColumnCount(2)
        self.log_table.setShowGrid(True)
        self.log_table.setHorizontalHeaderLabels(["Time", "Event"])
        self.log_table.horizontalHeader().setStretchLastSection(True)
        self.log_table.horizontalHeader().setSectionResizeMode(QHeaderView.ResizeToContents)
        self.setCentralWidget(self.log_table)
        self.show()

        self.threadpool = QThreadPool()
        self.keyboard_detector = KeyboardDetector()
        self.keyboard_detector.signals.keyboard_changed.connect(self.add_row)
        self.threadpool.start(self.keyboard_detector)


    def add_row(self, event: str):
        now = datetime.now()
        datetime_string = now.strftime("%Y-%m-%d %H:%M:%S")

        row_count = self.log_table.rowCount()
        self.log_table.insertRow(row_count)
        self.log_table.setItem(row_count, 0, QTableWidgetItem(datetime_string))
        self.log_table.setItem(row_count, 1, QTableWidgetItem(event))


    def closeEvent(self,event):
        self.keyboard_detector.stop()


def main():
    app = QApplication(sys.argv)
    window = MainWindow()
    app.exec()


if __name__ == '__main__':
    main()

- Atalanttore